Popular Astronomy

Vol. XXXIX, No. 7 AUGUST-SEPTEMBER, 1931

Whole No. 387

SHOOTING LIGHTNING

By JOHN W. BAECHLE.

About ten o’clock one night in May, a terrific thunder-storm swept down from Lake Erie and over St. Charles Seminary, Carthagena, Ohio. It was heralded by profuse lightning which flashed beautifully in the otherwise. inky black northern sky, but the storm was yet so far away that not a sound of the accompanying thunder could be heard. Be- catise On several previous occasions I had unsuccessfully attempted to take a picture of lightning, I most readily grasped this opportunity, especially since I had never before seen lightning occur at such regular intervals that I could actually rely upon its continued recurrence. Quick- ly I secured a companion to help me set up my camera so that I could obtain the picture before the storm would be upon us in all its fury.

Nature herself seemed very propitious for most of the lightning was in a very ideal part of the sky, for I was able to include in the panorama four tall pine trees, which when silhouetted against the lightning- illumined sky took on the aspect of four stalwart sentries of the night. Low over the eastern portion of the horizon, which was to be included in the picture, hung heavy foreboding clouds which could be seen only be- cause the upper part of the lightning there was abruptly hidden by them. Such was the scene as I made the accompanying picture of lightning (Plate VIII).

I had one difficulty, however, for before I could focus the lightning on the ground glass of my camera, the flash would again be gone; and I could not focus on anything else, for all was ebony black. Then I thought of my high-powered flash-light, and so I had my companion go about 100 feet away and throw the light directly into the lens of my camera. It was comparatively easy to focus the camera on the steady rays from the flash-light shining out in the darkness of the night. I knew that when an ordinary camera is focused on 100 feet, everything up to infinity is supposed to be in focus, so I figured that the lightning should also be in focus, for while it was many miles away, it was cer- tainly included in “Infinity.”

Then without using any supplementary lens on my Conley F 7.7 camera, I gave the film an exposure of probably thirty seconds. I did not really time the exposure, but merely left the lens open until I thought that enough lightning had been recorded on the film to produce a good negative. I knew there was no danger of over-exposing the film since between the various flashes it was too dark to affect the film at all. Until I had developed the film I doubted whether the film was able to

366 Astronomy Section of the A.A.A.S.

record the lightning during the fraction of a second which each flash lasted, but with Eastman Panchromatic (Super-Speed) film and a good Anastigmat lens set at F 7.7 I found that such a picture of lightning was possible. In fact the picture shows even more than a naked eye could possibly perceive, for I’d defy anyone who saw the large flash of lightning to the left to tell me that with his naked eye he saw how the two main lines converged and then diverged again, or that he even knew there was any of the faint root-like forked lightning present as the picture shows. St. CHARLES SEMINARY, CARTHAGENA, OHIO.

ASTRONOMY SECTION OF THE A. A. A. S. (Report of the Pasadena Meeting)

By SETH B. NICHOLSON.

The astronomical section (D) of the A.A.A.S. met with the Astro- nomical Society of the Pacific in Pasadena during the week of June 15-20. The Huntington Library and Art Gallery, the California Insti- tute of Technology, and the Mount Wilson Observatory of the Carnegie Institution of Washington were hosts for the meetings and many oppor- tunities for scientific fellowship were provided in addition to the regu- lar sessions for the presentation of papers.

Among the research exhibits was one which illustrated with models and photographs some of the recent developments in astronomical equipment and results. A carefully planned exhibit of photographs and diagrams illustrated and explained the methods used in determining the distances and distribution of nebulae and showed the results that have been obtained in such explorations of space. One of the spectro- helioscopes designed by Dr. Hale for the systematic study of solar activ- ity was also exhibited.

On Tuesday morning Section D and the Astronomical Society of the Pacific attended the symposium of the American Physical Society which dealt with the present status of the problem of nuclear structure. In the afternoon Dr. Hale’s Solar Laboratory of the Mount Wilson Ob- servatory was visited and in the evening the new observatory of the Pasadena Junior College with its 20-inch reflector was open to the astro- nomical societies.

On Wednesday morning a program of invited papers was presented in which Dr. Seares and Dr. Hubble of the Mount Wilson Observatory told of their latest results. Drs. Seares and Hubble presented their observational results, the first relating to the general absorption in space and the second to the distribution of extra-galactic nebulae, while Dr. Tolman told of his theoretical conclusions regarding the entropy of the universe as a whole. The societies were especially fortunate in having

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Seth B. Nicholson 367

Professor R. H. Fowler of Trinity College, Cambridge, England, who reviewed and explained the significance of the recent speculations about the internal structure of stars. Following his talk Dr. Dunham read a summary of a paper by Professor H. N. Russell of Princeton which dealt with certain phases of the same subject.

In the afternoon the machine shops of the California Institute of Technology Astrophysical Laboratory were open and the visitors saw the machines with which much of the 200-inch telescope and its equip- ment will be built. The evening was spent on Mount Wilson where everyone enjoyed the opportunity of observing with the 100-inch Hooker telescope and the 60-inch reflector. Early the next morning the solar tower telescopes were inspected and later the regular session for papers was held in the dome of the 100-inch telescope. The novel ex- perience of meeting in the dome in view of the big telescope added much to the enjoyment of this session. The ability of the dome to maintain a low temperature throughout the day was amply demonstrated and the sunshine outside was appreciated by everyone at the close of the session. An outdoor luncheon, picnic style, at the “Monastery” afforded an opportunity for a good visit before returning to the valley. That evening several of the visiting astronomers made a pilgrimage to Santa Ana to see the long pipe line and instrumental equipment used by the late Dr. Michelson in his last determination of the velocity of light.

On Friday the session for the presentation of papers was held in the library of the Mount Wilson Observatory in Pasadena and in the after- noon the laboratories and shops there were open for inspection. A dinner at the Huntington Hotel with the Mathematical and Physical Societies and an illustrated lecture by Dr. Hubble in the eevning closed the astro- nomical program of the meeting.

At the sessions for technical papers a great variety of subjects was discussed. No attempt will be made here to review or even mention all the papers, 33 in number, that were presented. Practically all phases of astronomy were covered and the societies were given a comprehensive account of recent progress, especially at the four large observatories of the west.

The meetings were unusually well attended, with representatives from the Lick Observatory, Goodsell Observatory, Lowell Observatory, the Students’ Observatory at Berkeley, the Adler Planetarium in Chicago, Perkins Observatory, Stewart Observatory, and the Dominion Astro- physical Observatory in addition to those from the colleges and observa- tories of Southern California. The opportunities for visiting and for informal discussions not listed on the printed program were, therefore, numerous and added greatly to the success of the meetings.

CARNEGIE INSTITUTION OF WASHINGTON, Mount Witson OsservatTory, Jury 10, 1931.

368 Globular Clusters and the Galaxy

GLOBULAR CLUSTERS AND THE GALAXY*

By EDWARD HARRISON, M.A., F.R.A.S.

The conception that the Galaxy is a spiral nebula seems to be accepted. It must, however, be a very old spiral which in the course of its wander- ings through space has collected innumerable other systems and so formed the immense structure it presents. Shapley well sums up the matter when he says, “Numerous conditions suggest that the Galaxy is a heterogeneous assemblage of unequally organised parts. . . . the galactic system may be largely composed of disintegrating clusters.” In another paper he puts it more pithily, saying, “the Galaxy is a growing composite of disintegrating minor systems.”*

It is noteworthy that the different classes of the heavenly bodies have varied and distinctive velocities. Curtis states these to be :?

For the stars 10 to 30 km/sec For globular clusters 300 km/sec For spiral nebulae 1200 km/sec.

Others’ put the mean speed of the globular clusters at 150 km/sec.

If, then, the Galaxy is a spiral nebula it must be travelling through space at an enormous speed, and it is difficult to imagine any other form of motion for it than that of a quoit or discus, and this view is adopted by the majority of astronomers.

It is important that we should know, if possible, the velocity and di- rection of motion of the Galaxy. From observations on spiral nebulae estimates have been made by Young and Harper,* Truman, Wirtz, and Lundmark,® and the average of the estimates of velocities is —692 km/sec, while the directions vary in galactic longitude from 354° to 35°, and the galactic latitude averages about —30°. The mean direction, then, is -++-15° galactic longitude, but for the present we will take a broad view and consider the direction to lie somewhere in the segment 0°-30°, and assume that the speed of the galaxy is three times that of the average globular cluster.

We will now consider a few of the salient features of the globular clusters.

Compared with the stellar distribution in the neighborhood of the sun the concentration of stars in the globular clusters is astonishing. A study of Messier 3 discloses that in equal spheres there would be only four or five stars around the sun compared with 15,000 in Messier 3. They are the nearest of the extra-galactic bodies, and only about a hundred are known. With very few exceptions they are all approaching the galaxy which exercises a powerful pull on them, and accelerates their velocity. Thus of ten studied by Slipher,® the five more remote have a mean

*Adapted from a paper read before the Hull Astronomical Society, England, April, 1929.

Edward Harrison 369

velocity of 133 km/sec, while the five nearer ones average 155 km/sec.

A suggestion regarding their origin has recently been put forward by Sir J. H. Jeans. When he announced his theory of the development of spirals in 1923, he regarded the condensations in the spiral arms as em- bryo stars. More recent investigation, however, has shown him that these, at any rate those which are first formed, are far too massive to be single stars; that indeed they contain sufficient material to form thous- ands of stars." Further than that, dynamical theory has indicated that they would be thrown off the revolving nebulae by centrifugal force, and so might very well account for the production of globular clusters. This startling theoretical conclusion receives observational support by the study of such nebulae as M 51 and M 101, both of which are figured in most of the modern books on astronomy, and in these one can almost see the little masses being shed. Lundmark® and also Perrine note a re- lationship between these two classes of celestial bodies. Acceptance of this hypothesis implies the presence of innumerable globular clusters in space mOving in every conceivable direction. How is it, then, that only about a hundred are known? The explanation probably is that as they are only small objects compared with the parent nebulae, they defy de- tection until they are comparatively very close to us.

We can now form a mental moving picture of what is in all probabil- ity happening. The Galaxy is travelling like a quoit and gathering up all the structures it encounters. As its speed is of the order of three times that of the globular clusters, it follows that it must be either meet- ing or overtaking them, with the possible exception of one or two clusters, here and there, with abnormally high velocities. We should expect, then, to find that all the globular clusters were on the advancing moiety of the Galaxy; and, further, as the movement is quoit-like, there should be an equal number on the upper and lower faces. Hinks® was the first to point out that the globular clusters were all found on one- half of the Galaxy, and, later, Shapley’s investigations confined them nearly all to one-quarter,’® viz., galactic longitude 0°-270°, and showed that there are none at all in the opposite quadrant. Further, the 69 globular clusters with which he worked were very equally divided be- tween positive and negative galactic latitudes, and that there was a band of avoidance exactly in the galactic plane presumably due to the pres- ence of obscuring matter.”

Now Shapley estimates that, within 125 million years, more than half of the known globular clusters will have entered the Galaxy, that is one is absorbed every two or three million years. Astronomically speaking, 125 million years is a mere moment, and if the inclusion of so many clusters within the Milky Way is imminent, it is only reasonable to suppose that many have been absorbed in the past.

If this be the case, what has happened to them? There are no globu- lar clusters in the Milky Way, but, on the other hand, there are many clusters which are not “globular,” but are of a more diffused, open character, which naturally leads one to ask whether the globular clusters

370 Globular Clusters and the Galaxy

after their inclusion are converted into open clusters? A priori it would seem that this was very likely. Imagine a dense globular cluster im- mersed in the immensity of the Milky Way, encompassed by countless stars, each of which is exerting a gravitational pull on it. Should we not expect that it would be teased out into a more open form? Well, what do we find? According to Shapley,’? “the open clusters occur only in low galactic latitude, and they do not show the avoidance of the Milky Way exhibited by the globular clusters. In fact they occur in the dense stellar regions where globular clusters are not found, and they do not occur in the extra-galactic realms where globular clusters are. This apparently complementary distribution of the two types of clusters is of high importance for the hypothesis which derives the galactic system originally from stellar clusters and obtains the open groups of the Milky Way from the extra-galactic globular organizations.” A special survey was made with the result that “the evidence grows continually stronger that open and globular clusters occupy regions of space that are mutual- ly exclusive.” We have, then, a quickly moving Galaxy, travelling through space which is dotted all over with globular clusters which are moving in all directions at, on the average, about a third the pace of the Galaxy.

Slipher found that the velocities of ten globular clusters, which he ex- amined, varied from +225 to —410 km/sec which is a range of 635 km/sec, which may be regarded, provisionally, as consisting of 150 due to the clusters and 480 for the Galaxy. Slipher’s figures, however, show that although 150 km/sec may be taken as the average rate there is a considerable range in their velocities. Thus, one (N.G.C. 6333) is re- ceding at the rate of 225km/sec. This is no doubt exceptional, but it makes one ask, are there any globular clusters overtaking us?

Shapley’s diagram shows three in the segment 180°-210°.

Apart from these exceptions Slipher’s list has one at +10, one at —10 and one at +10, which means that we must admit that some are moving at very much the same velocity as ourselves, so that although we may be right in assuming the average cluster velocity to be 150 km/sec, and to have a ratio of about 1 to 3 compared with the galactic velocity, yet it may range from 0 to 6. It must be remembered that these observed velocities are all radial, so that it is the radial component of globular clusters travelling obliquely to our direction that is observed. This ex- plains the large percentage of clusters having apparently such low in- trinsic speeds.

Figuring these movements to ourselves, let us endeavor to predict, as far as possible, the distribution of the galactic clusters.

It is clear that we may divide the galactic clusters into two classes which we will for convenience designate as the “overtaken” and the “met,” the latter probably being about twice as numerous as the former (vide appendix).

Now, the mode of admission of the two classes into the Galaxy will be very different. Those overtaken will enter in a passive manner, their

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Edward Harrison 371

speed of ingress varying inversely with their intrinsic velocity. Thus, those travelling directly away from us at almost our own pace will be caught only after a long stern chase, and when overtaken will be lightly licked up and engulfed by the Galaxy. Once inside, they will not tend to travel far inwards, as what little velocity they had on admission will be rapidly reduced to that of the Galaxy, and they will quickly disintegrate and cease to exist as “clusters.” Let us call these sub-class A. Those having a lower intrinsic radial velocity will be overtaken more easily, that is after a shorter stern chase, and so will enter with a greater velo- city and consequently advance deeper into the Galaxy before their speed is reduced, and will therefore remain as “clusters” longer than those of sub-class A. We will name these sub-class B.

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Figure 1.

Bearing in mind that the globular clusters are moving in every possi- ble direction, it is clear that they will enter the Galaxy at all angles. Sup- posing, then, that we could look down on the Galaxy we should expect to find that the advancing portion of the Galaxy would contain the ‘‘over- taken” clusters, and that these would be divided into two zones, an anterior and a posterior, which would blend gradually with each other, but the posterior would contain more clusters. Further, we should ex- pect to find that the clusters in the anterior zone, (sub-class A), were of a more open character, i.e. commencing disintegration being visible.

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Figure 2.

On the other hand the “met” clusters will enter in a distinctly more agressive manner. As they come with an intrinsic velocity which must be added to, instead of subtracted from, the galactic velocity, they will go deeper and will not disintegrate so quickly, and, as we have seen that there will be about twice as many in this class, there should be more clusters found in the posterior half of the Galaxy. Furthermore, as

372 Globular Clusters and the Galaxy

there is a very decided difference in the average velocity of entrance of the “met” and “overtaken,” we should expect to find a decided line of demarcation between these two, though not of course absolutely abrupt, and, moreover, this division should be at right angles to the direction of galactic movement. It will not be absolutely abrupt as those globular clusters travelling at right angles to the course of the Galaxy will have no intrinsic radial velocity and would so bridge the gap between “met” and “overtaken.”

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Ficure 3.

Figure 1 shows the anticipated distribution supposing that we could look down on the Galaxy, but it only indicates the dispersion in galactic longitude. As the clusters come in at all angles there will be some dis- persion in galactic latitude, and the degree of this dispersion will depend

Edward Harrison 373

on the distance travelled within the Galaxy, hence we should expect to find the spreading greater in the posterior portion. A glance at Figure 2 will make this clear.

Now, the actual distribution of clusters within the galaxy is closely in accord with our expectations. Figure 3, which is made from Melotte’s'* catalogue of star clusters shown on the Franklin-Adams chart plates, shows the positions in galactic longitude and galactic lati- tude for all the clusters. Galactic longitude is marked in degrees on the circumference, while the galactic latitude is indicated by a + or — marking the position of each cluster.

We are assuming the Galaxy to be moving in a direction between 0° and 30°. A mere glance at the diagram shows that there are many more clusters in the posterior portion, and that they are more widely dispersed in galactic latitude, the maximum range being found between 150° and 210°. Moreover, the anticipated line of demarcation between the two classes of clusters is very obvious, stretching from 90° to 310°, at right angles to the line from 20° to 200°. This is in accord with the assumed

direction of galactic movement. c ° '

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Figure 4.

The distribution in galactic longitude is more clearly shown in Figure 4, made from Melotte’s catalogue, the upper thick line marking the total number of clusters found in each segment of 30°. The first thing that strikes one on looking at this curve is the very marked maximum in segment 180°-210°, which is the one exactly opposite the advancing seg-

Figure 5.

The circle represents the Galaxy. A globular cluster situated at A and having an intrinsic motion in the direction AB will pass through the center of the Galaxy. This is what we will term a “direct hit.” A cluster moving in the direction AC will be deflected as it approaches the Galaxy and will take the course AD.

374 Globular Clusters and the Galaxy

ment 0°-30°. This might have been anticipated, and its existence sup- ports the assumption that the direction of galactic movement is between 0° and 30°. In Figure 5, let the circle represent the plane of the Galaxy, and suppose a globular cluster at A is moving directly towards the center of the Galaxy, which is itself moving in a diametrically opposite direction, viz., both along the line BEA. The globular cluster will, pass- ing through the center, reach the point B. Let us call such an encounter a “direct hit.”

Now, the gravitational attraction exercised by the galaxy on the glob- ular clusters will be directed towards its center. Imagine a globular cluster at A pursuing a course AC, so that if gravitational attraction were absent it would reach the point C; but the galactic attraction de- flects it from this straight course and impels it to arrive at D, and so makes it approximate to the line taken by a “direct hit.” We ought, therefore, to have expected to find more clusters in segment 180°-210° ; and further than that, the increase should have been at the expense of the adjacent segments, which ought then to contain fewer clusters than the normal. These considerations would, perhaps, have justified a fore- cast and this forecast, had it been made, would have been verified in an almost uncanny degree, for an increase of 11 in segment 180°-210° is ac- counted for by a loss of 4 (i.e. 17 —13) in segment 150°-180° on the one side, and of 4 (1.c. 16 — 12) in segment 210°-240°, and 3 (i.e. 16 — 13) in segment 240°-270°, on the other side, as reference to Figure 4 will show. The dotted line shows the curve thus smoothed out, and it then becomes practically a straight line extending through eight seg- ments, viz., 90°-120° to 300°-330° inclusive.

This remarkable finding almost forces one to inquire further and examine the details of the distribution within segment 180°-210°, in or- der to see if we can lessen the limits of the adopted direction of galactic movement. Dividing the segment into three, of 10 degrees each, Melotte’s tables show that the total number of 27 is made up of 14 in the central sub-division, and of 5 and 8 on either side, which would seem to indicate that the direction is between 10° and 20° galactic longitude. The mean of the observations already mentioned, viz. 15°, is within this, as is also one of Lundmark’s, viz. 17°. Thus, incidentally, we have two quite independent and concordant pieces of internal evidence indi- cating that the Galaxy is pursuing a course along the line drawn from 200° to 20° galactic longitude. It is as if the Galaxy had produced two records of its own path through space, like the tracks left by two cart wheels, or the trail of foam in the wake of a steamer.

The other important feature of the curve is the sudden and marked fall in segments 330°-0° to 60°-90°, which of course corresponds with the line already noticed stretching across from 90° to 310°, (indicated by vertical dotted lines in the diagram), which was considered as that separating the “met” from the “overtaken” clusters.

We will now consider the distribution in this advancing portion of the Galaxy, taking first:

Edward Harrison 375

Sub-Class A. These are what we have pictured as lightly gathered up and engulfed after a prolonged stern chase, and at first one would think that they would be very few in number. Examination, however, of Slipher’s table (vide appendix) shows that out of his ten clusters two (N.G.C. 6626 and 7089) might well be placed in sub-class A; that is to say twenty per cent. We have seen that Shapley prognosticates that more than half of the globular clusters (say 50) will enter the Galaxy in 125 million years, so assuming that this rate has been the same in the past we should have taken up ten sub-class A clusters during the past 125 million years. These, we have anticipated, would not have remained as clusters but would have rapidly disintegrated into clouds of stars. Well, those wonderful star clouds in Sagittarius, in Scorpio, in Ophiu- chus, in Scutum and up to Cepheus, are in the advancing portion ex- tending from 60° to 320° galactic longitude.

These stellar clouds have been accounted for by assuming that the sun is situated eccentrically on the opposite side of the Galaxy (galactic longitude 145°) so more stars are seen here as we are looking through a greater depth of Galaxy. But, on the assumption that the stars are fairly evenly distributed, seeing through a greater depth should still show an even, though denser, distribution. Now, Barnard’s beautiful plates of the Milky Way give anything but an impression of homogen- eity. The stellar increase suggests that they are additions forming colossal clouds, many having well marked margins, and giving no indi- cation of uniformity. Further than this, their appearance suggests dis- integration, and this has been pointed out by Barnard himself, as he says in his description of plate 42 of a region in Sagitta (galactic longi- tude 22°) “All along the edge of the cloud—and this is noticeable in other parts of the Milky Way—the impression is strong that the stars are moving out, as if disintegration were in progress.”

Another interesting feature of these star clouds is that they seem to indicate that the Galaxy is rotating in the direction 360°-330°-300°, as the more definite margins are all on the sides having the smaller galactic longitude which is what one would have anticipated on the assumption that this was the direction of rotation. This rotation explains the distri- bution of the clouds extending as far as 320° (i.e. 40° from 0°), those now seen at 320° being probably the oldest, having been carried round from segment 0°-30°, and this supposition is supported by Barnard’s photographs, particularly by Plate 51 in which the gradual dissipation of the advancing margin is well brought out. Here it is seen that the well-defined margin in galactic longitude 14° is retained as far as galac- tic longitude 354°, after which it gradually loses its clearness till it be- comes lost at 324°.

We have already anticipated that the sub-class A zone would be char- acterized by the presence of clusters of a more open variety. We have seen grounds for assuming that the rapidity of disintegration of a clus- ter will vary inversely with its initial speed. We should, then, expect to find the clusters had varying degrees of concentration in all parts of the

376 Globular Clusters and the Galaxy

Galaxy, but as sub-class A zone contains the most slowly moving clusters more of these should be opened out. Is this the case?

Fortunately Melotte has divided the galactic clusters in his catalogue into three classes, viz.,

1. Loose clusters having regular, well-defined outlines.

2. Loose clusters, often of a few stars only, and of irregular outline.

3. Coarse clusters, only 14 in number, e.g. Pleiades.

We thus have data for an answer to our query, and for our present purpose we will take the second and third groups together and call them “open” clusters, while the first class we will designate as “close” clusters.

In Figure 4 these two classes are plotted, the “close” class as a thin continuous line, and the “open” as a broken line; the sum of the two giving, of course, the upper heavy line we have been considering. We find a very definite pronouncement in favor of our expectation. In every part of the curve, with the exception of the advancing segments, the thin line is well above the broken one. This is, however, reversed in the two central segments of the advancing portion, while in segment 0°-30°, which we have taken to be the leading segment, all the clusters are of the “open” variety. Another factor in the causation of the fall in the curve, and which makes it deeper, is the absence of those clusters which have already disintegrated into star-clouds. The actual number of clusters found between 90° and 310° is 40. If we take Slipher’s pro- portion of 1/5 as those disintegrated, there would have been 50 origin- ally absorbed, ten of which have ceased to exist as clusters.

The question then arises, would so few clusters account for the ex- isting dense stellar clouds? A discussion of this point would carry us beyond the scope of this paper, but it may be pointed out that, as already noted, the density of stars in the globular clusters is very great, and Jeans has said that the stellar density in a globular cluster “must be very great indeed in comparison with that in the galactic system.” Then a globular cluster would not disperse into a spherical form, but would rather tend to assume the shape of a meniscus, as the attraction towards the galactic center will be far greater than that of the periphery.

Another point of interest is that, taking 50 as the number of “over- taken” clusters, there would then have been 173 in all, so that the “met” would number 123, just two and a half times as many, and this means that the Galaxy is travelling two and a half times as fast as the average globular cluster, which is well in accord with the adopted number (vide appendix).

Observational findings, then, are in very close accord with theoretical anticipations, thus:

1. The visible globular clusters are all on the advancing half of the Galaxy, their apparent maximum at galactic longitude 325° being due to the eccentric position of the sun.

2. The line suggesting demarcation between “overtaken” and “met” clusters is at right angles to the assumed direction of motion, and is clearly defined.

Edward Harrison 377

3. The ratio between the numbers of “met” and “overtaken’’ clusters would seem to indicate that the Galaxy is moving at the rate of two and a half times that of the clusters.

4. The distribution of galactic clusters is that anticipated theoretical- ly, and has provided two independent and concordant pieces of internal evidence as to the direction of galactic movement, which is very nearly the mean of the estimations of several observers.

5. The presence and position of the stellar clouds accord with theory.

6. The ratio between the number of “open” and “close” galactic clus- ters, in different zones of the Galaxy, agrees with theoretical expecta- tions.

APPENDIX.

Table to show the relationship between the speed of the Galaxy to the numbers of “met” and “overtaken” galactic clusters.

Ratio of Speed of Galaxy to Ratio of “Met” to “Overtaken” Speed of Clusters Globular Clusters BP Aiea ieee oak ok Reed eee ee eee 3 3 ae rR ee ea ie ee ee eure eee 1.68 Be piste oe eke bakes Se od eke eas oo SLIPHER’S RADIAL VELOCITIES OF TEN GLOBULAR CLUSTERS. N.G.C. mA. Dec. Vel. Gal. Lon. Gal. Lat. 7 : km/sec sf . 5024 197.0 +18.7 —170 320 +78 5272 204.4 +28.9 125 15 +80 5904 228.4 + 2.5 +. 10 333 +45 6205 249.5 +36.7 — 300 18 +38 6333 258.3 —18.4 +225 333 + 7 6341 258.5 +43.3 —160 32 +32 6626 274.6 —24.9 + © 337 0 6934 307.3 + 7.1 —410 22 —24 7078 321.3 +11.7 - 95 31 —29 7089 aee.1 — 1.3 — 10 21 —34

The average direction in galactic longitude is 350°, not so far from the aver- age we have taken from estimates made from spirals.

REFERENCES.

1. SHApPLEY. Astrophysical Journal, Sept., 1919, p. 108; “The Galactic System.” Address to the British Astronomical Society, May 31, 1922. Nature, Oct. 21 and 28, 1922. Popular Astronomy, May, 1923.

. Curtis. Scientia, Vol. XXXV, No. CXLI-I, 1-1-1924, p. 4.

. Jeans. “Astronomy and Cosmogony,” p. 25.

. Younc AND Harper. “The Solar motion as determined from the radial velo- cities of Spiral Nebulae.” Journ. R.A.S. Canada, 1916, p. 134.

5. LunpMArK. “Relations of the Globular Clusters and Spiral Nebulae to the Stellar System.” Kungl Svenska Vetenskapsakademienshandlingar. Band 60 No. 8. London. Wesley and Son.

. SHApLEY. Pub. Ast. Soc. Pac., Feb., 1918.

. Jeans. “Astronomy and Cosmogony,” p. 371.

. LunpMARK. ibid. No. 9, p. 34.

. Hinxs. “Nineteenth Century,” May, 1927, and M.N.R.A.S., LXXI, (1911), p. 176.

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378 Globular Clusters and the Galaxy

10. SHApLEY. Numerous papers in Astrophysical Journal, and Pub. Ast. Soc. Pac., Feb., 1918.

11. Fatu. “Elements of Astronomy,” p. 252-3, and SeAres. Nature, May 5, 1928.

12. SHAPLEY. Astrophysical Journal, Sept., 1919, p. 108.

13. Memoirs R.A.S., Vol. LX, Part V.

ADDENDUM,

Since writing the above, Shapley’s Monograph on “Star Clusters,” containing a catalogue of 249 galactic clusters, has appeared; also Trumpler’s paper (Lick Observatory Bulletin, 420) with 334 open clus- ters. Publication of this paper has, therefore, been delayed pending ex- amination of these two recent communications.

Working with Shapley’s list the minimum is confined to the segments 0°-30° and 30°-60° (each containing 10 clusters) rising rapidly on either side to 21 and 22. It is, thus, more nearly symmetrical than Melotte’s, and so more in accord with theoretical anticipations. Shap- ley’s gravitational maximum at 180°-210° is somewhat abortive. This is partly due to the omission of two of Melotte’s clusters, and when al- lowance is made for this the resemblance is restored.

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344

Ficure 6.

A marked divergence from Melotte’s curve, however, is at 300°-330° where there is a maximum of 36, and a lesser one of 30 at 240°-270°. Figure XII, 4, in Shapley’s book shows the galactic clusters projected on to the galactic plane, so that galactic longitudes are indicated, and also the distance of each cluster from the sun. Inspection of this dia- gram discloses that the maximum in these two segments is due to agglomerations of clusters at the apices of the two segments, that is very near the sun. When we remember that the direction of the maxi-

379

Earthshine

mum of the globular clusters, 327°, falls within segment 300°-330°, we are provided with a clue, viz. the eccentric position of the sun, and by moving the centre a few hundred parsecs along 327°, these maxima dis- appear and the curve approaches very closely to that of Melotte’s, of course on a higher level.

Trumpler, who gives a similar diagram of 334 clusters and, after recording the results of several observers, concludes that the galactic centre lies 350 parsecs distant from the sun in galactic longitude 325° Taking this as the centre, counts of the clusters in each segment result in the curve in Figure 6, Melotte’s curve, the broken line, being placed below it for comparison.

We see, as was the case with Shapley’s, that the minimum is more marked than Melotte’s, and is confined to two segments.

It is all on a grander scale; the opposing maximum extends over two segments, the gravitational minima on either side being very pro- nounced. A very noticeable symmetry exists about the maximum, 150°- 210°, extending on either side to 60°-90°, and 270°-300° respectively, this covers eight segments. Then in 300°-330° and 330°-0°, we have what may be considered a normal distribution, followed by the minimum extending over two segments.

These two segments of “normal” distribution somewhat mar the sym- metry of the whole diagram, and incline one to ask whether galactic rotation would account for it.

Respecting the distribution in galactic latitude, both Shapley and Trumpler emphasize the increase in the spread in the posterior portion.

9 ParK AVENUE, HULL, ENGLAND.

EARTHSHINE A Crayon Sketch

Evening— And the black edge of night already laps Westward where the stark outline of trees is set In the softening glow of day

Now almost gone.

New moon—

And its silver rim of light low hung in graying sky

Halos a softer radiance as though

The darkness of the lunar night was lightly brushed With dust of stars.

And now— Against the background of the waning twilight And an earthlit moon A tiny bat flaps dusky wings—, And day is done. STERLING BUNCH. Knoxville, Tennessee.

380 Accuracy Required in Parabolizing a Mirror

ACCURACY REQUIRED IN PARABOLIZING A MIRROR

By FRANKLIN B. WRIGHT.

Many amateurs are making their own reflecting telescopes, and the number is increasing steadily. The practical methods used in grinding, figuring and testing the objective are clearly described in the book “Amateur Telescope Making,” published by the Scientific American Publishing Company. In his own efforts along these lines the writer has felt the need for more definite information concerning the accuracy required in shaping or figuring the objective mirror. The question is discussed here and there in the literature but not in a manner immedi- ately and simply applicable to the amateur’s own reflector. A number of inaccurate statements are also to be found. For example, the article on diffraction of light in the Encyclopaedia Britannica (11th ed. Vol. 8, p. 245) concludes by an indirect method of reasoning frequently em- ployed that a spherical mirror of 3 feet focus can not exceed 2.5 inches in aperture without introducing a surface error greater than A ~ 8, while the formula for e discussed below shows directly that an aperture of 3.5 inches is permissible for the focus and surface error there as- sumed,

In figuring the objective mirror accurately to the parabolic shape re- quired to bring the rays of light to a perfect focus, the mirror maker uses the Foucault knife-edge test as his guide. This simple but beautiful test is usually applied by amateurs at the center of curvature of the mirror in the following manner, since this requires less apparatus than when tested at the principal focus. The mirror is set on a stand with its axis about horizontal. A lamp having a metal shade with a very small hole punched in it serves as a point source of light. This remains in a fixed position throughout the test near the center of curvature slightly to one side of the axis. The light reflected from the mirror then comes to a focus near the lamp on the other side of the axis. A razor blade or similar straight edge, fastened on a stand, is used to locate this point accurately in a manner fully described in the reference given above. When the mirror is spherical the rays from all zones of the mirror focus precisely at this point. But when the mirror is parabolic, the rays from any narrow zone a distance r from the center come to a focus farther away from the mirror than the rays from the central zone of the mirror by an amount approximately given as d—=r* +R, R being the radius of curvature.

In parabolizing a large mirror measurements are made for a number of zones, but with mirrors of, say eight inches or less, only the outermost zone need be compared with the center, provided the general shape of the mirror appears all right when viewed as a whole with the knife edge. Considerable difficulty is experienced in figuring a mirror so that the measured distance d checks precisely with that given by the formula.

Franklin B. Wright 381

It is therefore worth while to inquire just what error may be tolerated without materially damaging the definition of the finished telescope.

In order to answer this question, consider the spherical and parabolic surfaces shown in Figure 1. The paraboloid A is supposed to be drawn with the same radius of curvature R for the center zone O as the spheri- cal surface B. The distance between the two surfaces at a distance r from the center is given to a close approximation by e == r* + 8R°, or more conveniently by e = D ~ 1024f* where D=2r and f= R ~— 4r. This expression may be derived easily from the equations of the two surfaces* after first expanding a radical appearing in the spherical equa- tion by the binomial theorem. It has been checked with calculations for several mirrors by Ritchey and Young.

Table I gives the values of e at the edge of mirrors of small aperture D and various ratios f of equivalent focal length to aperture. They have been expressed in terms of the wavelength of light by dividing e by A= 0.00002 inch, approximately representing visible light.

TABLE I. MAXIMUM DEPARTURE € OF SPHERICAL FROM PARABOLIC SURFACE. f Ratio D=4inches 6inches 8inches 10 inches 12 inches r r nN r

5 1.56 2.34 3.82 3.90 4.69

6 0.90 1.36 1.81 2.26 2.72

8 0.38 0.57 0.76 0.95 1.14

10 0.20 0.29 0.39 0.49 0.59

12 0.11 0.17 0.23 0.28 0.34

The process of parabolizing may conveniently be supposed to consist of polishing off a depth of glass equal to e near the edge of the spherical surface, although in practice it is usually the surface around the center rather than the edge of the mirror that is thus treated to obtain a parabolic shape. If the mirror receives only a partial correction, say 80 per cent of the theoretical amount e, then 20 per cent of e is the error of the resulting surface giving it the shape shown by C in Figure 1. For this surface the knife edge test in the form which has been outlined gives a measured distance of 80 per cent of r° + R between the knife edge positions for the central zone and any other zone of radius r.

Authorities generally agree that an error of surface of an eighth of a wavelength scarcely affects definition at all, and even twice this amount, or A + 4, has very little effect when the telescope is adjusted for best focus. Above this limit an appreciable scattering of light com- mences to take place. On first thought this seems to be a surprisingly large tolerance since the difference in the paths of the light rays from the center and edge of the mirror is twice the error of the surface, anda difference in path of A + 2 would surely be expected to produce a lot of destructive interference at the focus. However, the best focus for the surface does not correspond to the paraboloid of Figure 1, but rather

*R, K. Young: Jour. Royal Ast. Soc. of Canada, Jan. 1930, p. 17.

382 Accuracy Required in Parabolizing a Mirror

to another paraboloid (not shown) intersecting the mirror surface both at its edge and at its center. The error of surface which is here referred to is the nominal error useful for purposes of calculation, the actual maximum error being only about one-fourth as great when the telescope is properly focused for best definition, Contrary to what one might suppose, errors of surface even considerably in excess of these specified, do not enlarge the image of a star. The effect is rather to cause a cer- tain amount of scattered light around the image and brightening the surrounding diffraction rings. With an error of A +4 about 1.5 per cent of the light which should be concentrated at the focus is thus scattered.

This explanation has been made rather at length because diffraction theory is apt to be rather too involved in mathematical symbols for most of us who have not delved into the subject much further than a general course in physics. The subject has been discussed mathematically by Buxton in Monthly Notices of the Royal Astronomical Society, 81, page 547. Bell’s book, “The Telescope” (page 265, etc.) contains a discussion of the subject in non-mathematical language.

In view of these facts it may be safely assumed that if e is reduced to A + 4, the objective will perform well in service. It is better to under- parabolize a mirror somewhat, unless it is made of pyrex or quartz in- stead of ordinary glass. Most amateur telescopes are used more often

Franklin B. Wright 383

during the early evening hours when the temperature is falling than at other times. Falling temperature temporarily flattens the outer zones of a mirror tending to parabolize an under-corrected figure. The prac- tical thing to do is to finish the mirror with an error of surface at the outside edge of between 0 and A + 4, preferably about half way be- tween atA +8. Then good definition will be assured even when the temperature is not falling. Table II has been prepared on this basis for small Newtonian telescopes with ordinary glass mirrors to be used chiefly during the evening hours. The first three columns show the acceptable range of correction expressed in per cent of the knife edge distance dr? ~ R, and corresponding respectively to A+ 4, A + 8, and zero errors of surface at the edge of the finished mirrors. The remaining columns show the ratio of equivalent focal length to aperture for mirrors of various diameters to which the corrections of the first three columns are applicable.

TABLE II.

%. of Theoretical Correction Minimum Maximum Accept- Preferred Accept- f Ratio able Correction able D = 4in. 6in. 8in. 10in. 12in. —100 0 100 11.6 13.3 14.6 15.8 16.8 — 2 40 100 9.8 11.2 12.3 13.3 14.1 20 60 100 8.5 9.8 10.8 11.6 12.3 60 80 100 6.8 7% 8.5 9.2 9.8 80 90 100 5.4 6.2 6.8 7.3 7.8 90 95 100 4.3 4.9 5.4 5.8 6.2 95 97.5 100 3.4 3.9 4.3 4.6 4.9

To illustrate the manner in which computations of this sort may be made, consider a 10-inch mirror with an equivalent focal length of 60 inches. The f ratio (focal length to aperture) is 6. From Table I this has an error of surface at the edge of the mirror of 2.26\. The pre- ferred correction is such as to reduce this error to 0.125. This is (2.26 —0.125) -~ 2.26 or 94 per cent of the amount necessary to com- pletely parabolize the mirror. Similarly reduction of the error to 0.25A gives 88 per cent for the minimum acceptable correction. Table II gives the resulting percentage corrections with sufficient accuracy, so the mir- ror maker can read them (by interpolation when necessary) for prac- tically any mirror up to an aperture of 12 inches.

Suppose a zone % inch in width at the edge of this 10-inch mirror be compared with the central zone by means of the knife edge test. The outer zone is at an average distance of r= 4.75 inches from the center, and the radius of curvature is R= 60 * 2120 inches. The theoreti- cal distance between the two knife edge positions is therefore r? + R- 0.188 inch. This is the maximum acceptable correction. The preferred correction is 94 per cent of this or 0.177 inch, and the minimum accept- able correction 88 per cent or 0.165 inch. In contrast to this case con- sider a 10-inch mirror with a focal length of 90 inches. The distance between the two knife edge positions would be 0.079 inch and 0.125

384 Accuracy Required in Parabolizing a Mirror

inch for the minimum and maximum acceptable corrections respectively. This is twice as wide a range as in case of the shorter focus instrument and the correction is therefore considerably easier to measure within tolerable limits of accuracy.

Negative corrections in Table II indicate that the radius of curvature of the outer zone may even be left somewhat shorter than that of the central zone without harm. Mirrors of dimensions shown on the first line of Table IL should preferably be finished spherical. Even those on the second line may be similarly treated although about 40 per cent cor- rection would be somewhat better in these cases, particularly with the smaller aperture mirrors where temperature distortion is not likely to be as great as with the larger ones. Perhaps it would be well to empha- size the fact that these spherical mirrors are no makeshift affairs. A perfectly spherical 8-inch mirror with a focal length of 8 feet will usual- ly give better definition than one of 4 feet focal length that has been given an 80 per cent correction. In the writer’s opinion, it is failure to perform the above calculations that is responsible for the general con- dition found by Ellison, who says (Amateur Telescope Making, 2nd Ed., p. 98), “We have never yet seen a mirror of f 10 and upward, even by well-known makers, that was not over-corrected.” There is so little difference between a sphere and a paraboloid of long focus that correction is easily overdone.

It is amazing that more reflectors of small aperture are not made spherical with aperture ratios of from f 10 to f 13. Not only are they much easier for the amateur to make and test than those of shorter focus, but the aberrations for points off the axis are less, they give better results generally with ordinary 2 lens eyepieces, and are less critical of exact adjustment of the eyepiece to position of best focus. Perhaps it is due to the tendency to copy the relative dimensions of the larger pro- fessional instruments without inquiring very closely into the require- ments of the case that is responsible. It should be remembered that the larger instruments are used almost exclusively for photography where short focus instruments are desirable to obtain negatives of faint objects with a minimum of exposure time, and that the cost of mounting and the accessibility of the eyepiece end are increasingly important factors with increase in aperture. None of these limitations apply to a small instrument. A reflector 6 or 8 feet long is inexpensive to house and con- venient to use, and the amateur’s photographic efforts, if any, are likely to be confined to the brighter objects unless he is blessed with a pre- cision mounting that few of us can afford. It is perhaps significant that most of the early reflectors built before the advent of photography were of f 10 or longer, particularly those of moderate aperture.

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Planet P, Planets S and T 385

PLANET P, ITS ORBIT, POSITION, AND MAGNITUDE, PLANETS S AND T

By WILLIAM H. PICKERING.

Although we know the orbit of planet P much better than we did that of Pluto, formerly known as planet O, yet we can hardly hope to locate it with quite the same accuracy in the sky. In part compensation, how- ever, we find that it is probably a much brighter object, requiring a shorter exposure, which will at the same time eliminate many of the confusing stars. Furthermore it is located where the stars are fewer, whereas Pluto, in the position where the writer predicted it in 1919, lay in the Milky Way itself, when it was later found on the Mount Wilson negatives. It is thought probable that planet P lies within 2° of its pre- dicted orbit, thus reducing the number of plates required to photograph it, if a doublet is used. Even if an ordinary photographic telescope is employed, the number of plates would not be excessive.

10 530 290 250 210 170 180 90 50 10 +100

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+ 40

— 20

~ {es6 1es5 1828 1817 1e08 i799 1790 1781 1771 1761 Figure 1. Revisep Orsit OF URANUS PERTURBED BY NEPTUNE. As a result of our more accurate knowledge of the elements a, 1, and 3 of its orbit, we can modify our method of research quite materially. The first step, however, the graphical process, remains unchanged. It will be recalled that, in our paper entitled “The Next Planet Beyond

386 Planet P, Planets S and T

Neptune” (PopuLar Astronomy, 1928, 36, 143), we began by showing the general appearance of a perturbation curve. We shall follow the same procedure here. Figures 1 and 2, taken from that paper, show the perturbations of Uranus by Neptune and of Neptune by Pluto, after the original observations had been treated by the sinusoidal method. The abscissas give the dates and heliocentric longitudes, and the ordinates the observed perturbations in longitude after the pertur- bations due to all the known planets have been eliminated. In accord- ance with this method by making suitable changes in the elements of the sinusoidal curve we can modify the semi-major axis of the orbit of the known planet, as well as its eccentricity, and the argument of its peri- helion in a systematic manner, so as to diminish the sum of the squares of the deviations, and at the same time render the perturbation curve of the proper shape, as shown best in the case of the perturbation of Uranus by Neptune. This perturbation was so enormous, some fifteen to twenty times the size of those with which we have to deal, that the

180 140 100 60 20 540 500 260 220 186 +5

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1942 = 1924 1906 18689 # +1871 #41852 1885 18614 1796 19778 FIGuRE 2. ReEvVISED Orpit OF NEPTUNE PERTURBED BY PLUTO.

accidental errors do not deform it in any way, and it serves to show us at once the proper shape. e

It will be noted that the theory of this method is quite distinct from that of the treatment by least squares. In the latter the theory is that all irregularities in the curve are due to inferior observations and that the sum of the squares of these deviations should be reduced to its minimum value. In Figure 3 the upper curve shows the perturbations of Uranus, as observed at Paris and Greenwich based on Leverrier’s orbit. These observations and other later ones have been recently treated in an im- portant paper by Messrs. Morgan and Lyons of the U. S. Naval Ob- servatory using Newcomb’s orbit, and employing the principle of least

ar squ duc enc the an¢

cur rea abl

William H. Pickering 387

squares (Astronomical Journal, 1930, 40, 97). I have plotted their re- sults in the lower portion of Figure 3. It will be seen that their curve shows the same two perturbations, one at either end, separated by a long level region that was exhibited in mine (PopuLar Astronomy, 1928, 36, 356), although mine showed the first perturbation much more markedly. In the sinusoidal theory as here applied on the other hand, certain large irregularities of the curve are accepted as due to perturbations caused by unknown planets, while other portions of the curve that appear to be capable of being straightened out are made as straight as possible, re- gardless of what may happen to the large irregularities themselves. As

55° 530" 250° 187” 70° sage 267° 175° 80° +3°

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_ t 1940 1920 1900 1860 1860 1840 1820 1800 1760 Figure 3. PERTURBATIONS OF THE ORBIT OF URANUS.

a result of this procedure we shall find not only that the sum of the squares in the case of the early observations of Uranus is greatly re- duced, but that the curve is quite straight for over half of its circumfer- ence, and that the chief irregularities have now of themselves taken on the forms of perturbation curves similar to those shown in Figures 1 and 2.

If we believe that the two maxima at the beginning and end of the curve are due simply to errors of observation, and that the curve should really be a straight line, then the method of least squares is unquestion- ably the proper one to employ in deducing it, and we should regret that

388 Planet P, Planets S and T

the errors, especially the later ones are so large. On the other hand, if we believe that these two maxima are genuine and due to perturbations of some unknown outer planet, then the method of least squares should be rejected, and the sinusoidal method of reduction should be employed in its place. That is why I used it in the case of Pluto, and shall now use it again in the case of planet P. Nevertheless the two methods do give analogous results as we shall presently see, for it is almost impossi- ble to conceal a perturbation maximum, although it may be somewhat shifted in longitude, and its amount considerably modified, if other methods of reduction are employed.

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—- oO 1658 1648 1836 1628 1619 1810 1601 1792 17&4 1776

Figure 4. First PerturRBATION OF URANUS DUE TO PLANET P.,

In Figure 4 a portion of my early curve is shown plotted as dots upon an enlarged scale, and the same portion of the Washington curve, con- sisting of small circles, is plotted upon it. This latter we see has greatly flattened the results, that being the object of its computers. I have grouped certain similar observations of my early curve, based on Leverrier’s, and joined their centers of gravity. A few very discordant observations have been rejected. Since I believe that this portion of the curve represents a genuine perturbation of Uranus produced by the same unknown body that is producing the present discordances, I feel that it is a mistake to flatten it out. However, although flattened in the Washington curve, the perturbation has not been wholly destroyed, but its shape no longer resembles a true perturbation (see Figures 1 and 2) and its apex has been removed some 70° by artificially diminishing the deviations that occurred between 1800 and 1825. The sinusoidal re- duction on the other hand leaves the longitude of the apex nearly as

or sh Ww pe

tic re in re

William H. Pickering 389

originally observed at 1810 (see upper curve of Figure 3) while the shape of the curve is the same as those shown in Figures 1 and 2, which we know were actually due to perturbations, because in both cases the perturbing planet is now known.

Figure 5 gives a similar large scale drawing of the second perturba- tion shown in the lower curve of Figure 3. The dots as before give my reductions of the observations recorded in the upper curve of that draw- ing based on Leverrier’s orbit. The small continuous circles show the results of Messrs. Morgan and Lyons, discontinuous it will be noted in 1896, and the dotted circles some provisional results by Messrs. Ham-

Jf. sac? 300° 260° 220° 180 140? loo” oad oe +

+3°

+1° Ws iA“ 2 o° aaaein —-s o e e é ‘ — 1° Sod * 1932 1922 19129 1893 168 «(1876 1867 156 = (18A8

Figure 5. SECOND PERTURBATION OF URANUS DUE TO PLANET P.

mond and Morgan, kindly sent me by the Superintendent of the Wash- ington Observatory (Astronomical Journal, 1930, 40, 85). Their re- duction of the observations begins with the year 1894, but the earlier observations merely follow a course midway between the dotted and the continuous lines of Figure 5, and it seemed undesirable to clog the figure with too much material. They show a maximum at 300°, but not so marked as that at 350°. The level line of observations nearly coinciding with ordinate 0” is well shown in both series. The inclined crosses represent the observations made at Greenwich, and published in Monthly Notices, 1929, 89, 261, and the vertical ones at the end some provisional results, for which I am indebted to the Astronomer Royal. It will be noticed that all three series, Washington, Greenwich, and my own reduction, indicate that a pronounced maximum occurred in 1912, in heliocentric longitude 300°, and that this was followed by a smaller maximum at 350°, much less marked, although Washington makes it higher than Greenwich.

Attention should be called to the fact that the abscissas of the four

390 Planet P, Planets S and T

perturbations shown in Figures 1, 2, 4, and 5 are all on the same scale. The four perturbation curves therefore each have about the same length, measured on the orbit of the perturbed body. Uranus moves so swiftly, however, compared to the leisurely moving P, which is from three to four times as remote, that we should expect it to escape from its per- turbing power more quickly than the bodies in the first two curves, where the perturbing body is only one and a half times as remote, and therefore follows it further. The first two perturbations extend through 180° and 160°, but the last two through only 130°. The curve itself, therefore, without any computation whatever, gives us a hint as to the considerable distance of the unknown body. The dots in Figure 5 give a better shaped perturbation curve than the circles or crosses, doubtless for the reason already explained that I made no attempt to artificially modify the curve by weighting the observations. It was seen that the interval between longitudes 20° and 240° by a simple sinusoidal reduc- tion would come out a nearly straight horizontal line, and as it was a plausible hypothesis that there were no large unknown planets to per- turb Uranus in that part of the sky, an effort was made to make this part of the orbit as straight and as horizontal as possible, while the two perturbations were left to take care of themselves. As a result they both showed themselves to be true perturbation curves without any attention from the computer whatever.

Admitting that in the long level region extending through 220° of longitude, no large unknown planet disturbed Uranus, we can thus see how accurate were the observations as far back as the first half of the last century. It is certain that modern observations cannot be inferior to them, and it is therefore certain that the perturbation that now affects Uranus is a real one. It must be pointed out, however, that while it is true that no large planet perturbed Uranus in that portion of its orbit, yet there should have been shown a small perturbation due to Pluto, be- tween the years 1853 and 1863, and amounting to about half a second of are (PorpuLar Astronomy, 1931, 39, 3). It appears, therefore, that I unwittingly flattened my curve a little bit too much. Such small per- turbations, however, are really beyond our capacity to detect at present. At that time I believed that the perturbation shown in Figure 4 in 1841 was the real one due to Pluto, and so was led to an erroneous distance of that body. This fortunately did not affect its location in the heavens. Returning to Figure 5, we see that Washington was even more neglect- ful of Pluto than I, for they left a minimum in place of a maximum between 1853 and 1863.

Although the scales of the abscissas of Figures 1, 2, 4, and 5 are identical, the scales of the ordinates it will be noted are very different, especially for Figure 1. Figures 2 and 5 are on the same scale, but in Figure 4 it will be seen that even if we reject the first ten observations as erroneous, which I believe should be done, the maximum perturba- tion is still 6”, while for the second perturbation in 1912 it is only 3”. This difference at once suggests a rather high eccentricity of the orbit

William H. Pickering 391

of P, and that the planet was nearer to Uranus at the first perturbation than it was at the second. In my paper “The Orbit of Uranus” (Popu- LAR ASTRONOMY, 1928, 36, 360) it was suggested that the perturbation in longitude at 350°, Figure 5, was due to a moderate sized planet which we called S, somewhat nearer as well as smaller than P. If we continue the slope of the larger perturbation to longitude 350°, it will cross that longitude at 0”.7, and will allow the perturbation due to planet S a max- imum height of 1”.3. Giving the right hand slope of the latter pertur- bation a proper inclination will leave the height of the maximum of planet P equal to about 2”.2. There are a few minor peculiarities that may be mentioned here, on which all four of the perturbation curves agree. They are all sharply pointed at the top, and the left hand side is steeper than the right. In Figure 4 this latter is not marked, but is still true. The curves are not so steep near the top, on either side, as lower down, this change of slope giving them all a somewhat similar shape and appearance.

Having now given the planetary data on which we shall base our further deductions, we will turn to the cometary evidence. This matter has been already taken up at some length in PopuLar Astronomy, 1928, 36, 417, and 1931, 39, 321. It is only necessary therefore to touch on the subject very briefly here. In the case of the 21 comets belonging to class C, those whose aphelion distances lie between 75.5 and 209, 16 be- long to type P, those whose aphelia lie within 20° of a great circle of the sphere. The zone thus described covers one-third of the total area of the sky. Five aphelia lie outside of this zone, four of them being quite remote, and evidently these comets are in no way related to the others. That this arrangment is not due to chance we can readily see, if we con- sider that two of the 16 selected aphelia are required to define the zone, and that of the remaining 14 orbits of the group, the chance expressed by 3 raised to the 14th power is a considerable number,—a little short of five million. This number will, however, be reduced appreciably by the five discordant comets. The computation is easily made by a simple formula, but as it would involve considerable time to compute it, it is quite sufficient to say that the chance against the grouping of the 16 comets together being due merely to accident is many thousands to one. In other words they are certainly related to one another, just as are the comets in Jupiter’s family. Such being the case, the node and inclina- tion of the great circle are obviously those of the planet. Since these comets are coming at the rate of at least one in every nine years, and their average period is 480 years, there must be over 50 of them. More- over we only see those whose perihelia lie within the orbit of Mars, and some may well have perihelia extending to 10 or 20 times that distance, doubling or trebling their number. For comparison we may state that of the 41 comets formerly associated with Jupiter, only 22 have been known to return within the last 25 years, and it is improbable that we shall ever again see the others. In other words, we may say that the members of Jupiter’s family are constantly changing, and that 22 is

392 Planet P, Planets S and T

perhaps a fair average number at any one time. The implication is that planet P is a very massive body. In the first of the above mentioned papers it is shown in the case of Jupiter, Saturn, Uranus, and Neptune that the shortest cometary aphelion distance associated with them is nearly identical with the mean distance of the planet. This is of course what we should expect, because it is obvious that a planet cannot per- turb and capture a comet unless in some portion of its orbit it comes

near to the planet. We may make the following comparison of these distances :

PLANET MEAN DISTANCE CoMET Jupiter 5.2 4.1 Saturn 9.5 9.7 Uranus 19.2 19.6 Neptune 30.1 30.0

Jupiter is so massive that it naturally can hold a comet at a greater distance than the other planets. The shortest cometary aphelion associ- ated with planet P, as far as we know, is 75.5 units for comet 1857 IV, and we shall take that number as the mean distance of P, although we clearly know so few of the comets that are associated with it. The next shortest aphelion distances are as much as 87.9 and 89.0. The cor- responding period is 656 years. The adopted node is 351°, and the in- clination 37°. Bode’s law gives so accurately the distance of Pluto, 38.2 to 39.6, that it is interesting to note that it agrees well also with our assumed distance of ?. According to it the distance should be 77.2.

Although I have stated several times in print that the maximum per- turbation of the known planet does not come at the time of its conjunc- tion with the unknown, and that my method of locating the unknown has nothing whatever to do with the conjunction, yet, as I am aware that even prominent astronomers sometimes make that mistake, I wish to repeat the statement here. In the case of Pluto it was in conjunction with Neptune in 1891, but the maximum perturbation of the latter did not come until eleven years later. It is obvious that, if the unknown planet is beyond the known, at the time of the maximum _perturba- tion it will be several degrees behind it. In order to locate the unknown, we should know this number. Let us take the plane triangle SUN, and applying it to the discovery of Neptune, we found by the early measures, after treating them by the sinusoidal method, at the time of the max- imum perturbation of Uranus, that the angle at S was —8°.2, indicat- ing that Neptune was behind Uranus by that amount. The angle at U was 157°.9. In the case of Neptune and Pluto, after the orbit of the latter was well determined, it appeared that at the time of the maximum perturbation of Neptune, Pluto was —12°.4 behind it. The obtuse angle varied through a much greater range. The determination of the former angle is the only step in our method of location of an unknown planet that may properly be described as empirical, and the small difference between the two angles, 4°.2, was gratifying. In the case of planet P, I place double the weight on the result obtained with Pluto that I should

William H. Pickering 393 with the other, and have therefore decided that the angle at the Sun be- ween Uranus and P was —11°.0 in longitude.

It is regrettable that P has produced no observable perturbation hitherto of the planet Neptune. Neptune when it was discovered in 1846 was some 70° ahead of P, and since their overtake period is 220 years, no conjunction even with Neptune can be expected before 2020. Having only two perturbations of Uranus on which to depend, it might at first glance be supposed that we did not have sufficient data on which to compute an elliptical orbit, but it must be remembered that we also

9° os

27° Ficure 6. THe Orpits oF PLuTO AND PLANET P.

have the semi-major axis, and the ratio of the extent of the two pertur- bations. This ratio unfortunately, however, does not help us as much as it usually should, because both perturbations are interfered with by the assumed planet S. The two maxima occur far enough apart in Figure 5 to enable us to determine their relative importance, but in Figure 6 they coincide. We cannot tell therefore how much of the 6” is due to P. If we assumed that the same ratio held as in 1912, the two perturbations of P were for 1812 3”.8, and for 1912 2”.2, ratio 1.73. On the other hand if we make no allowance at all for S then the two

394 Planet P, Planets S and T

perturbations of P were 6”.0 and 2”.8, ratio 2.14. Whatever ratio we adopt will affect chiefly the value of e, and that is not of much conse- quence since it gives little aid in finding the planet. We shall for the sake of the computation adopt the ratio 1.90, which gives us for e the value 0.265,—a not improbable figure, and one not very different from that found for Pluto, of which the two best determinations so far pub- lished are 0.254 and 0.249. Our ratio 1.90 should be approximately inversely proportional to the square of the distances of P from Uranus at the times of its two maximum perturbations, measured on the plane of the ecliptic. In Figure 6 are shown the orbits of the four outer planets. The smallest circle shows that of the earth.

TABLE L. ELEMENTS OF THE OrsBIT OF PLANET P, AND OTHER DATA, Elements Other Data a Semi-major Axis 75.5 Magnitude, if like Pluto 15 e Eccentricity 0.265 Angular Diameter 122 i Inclination sf” Diameter in miles 44000 $3 Ascending Node gol” Present Annual Motion +0°42 w Argument of Perihelion 170°5 Parallactic Daily Motion —4378 P Period 656 Orbital Daily Motion +49 T Date of Perihelion 1742 Present Longitude 29825 Other Data Present Latitude —30°9 q Perihelion Distance 55.5 Present Right Ascension 20" 40™ Aphelion Distance 95.5 Present Declination —50° Present Distance 85.0 R.A. 10° or 20 years back 19*'53™ mw Longitude of Perihelion 172°9 Dec. 10° or 20 years back —55°2 # Mean Annual Motion 0°549 R.A. 10° or 20 years hence 21"14™ E Epoch 1932.0 Dec. 10° or 20 years hence —45°3 m Mass 49.6 Maximum perturbation in 1912 272

Magnitude, if like Neptune 11.2 Date of Opposition in 1931 Aug. 1

In Table I are given the elements of the orbit of P, and other data re- lating to the planet and its orbit. It will be noticed that its descending node coincides with its longitude of perihelion within the limits of the probable errors of the computation. We have already remarked that a planet that controlled so many comets, more apparently than any other planet in our system, must be very massive. We now find from its per- turbations of Uranus that its mass is half that of Saturn, 94.9, three times that of Neptune, 17.2, and fifty times that of the earth. It is there- fore the third planet in the solar system. When I first recognized its im- portance, from its comets, some twenty years ago, I mentally reserved for it the name Pluto as the son of Saturn, and the brother of Jupiter and Neptune, but unfortunately that small object planet O came round and perturbed Neptune some ten years before the liesurely P arrived and perturbed Uranus, and so received the name. Pluto should be re- named Loki, the god of thieves! A suitable name for P will now indeed be difficult to find when that planet is discovered.

Two values are given for the expected magnitude of P, one if in den- sity and albedo it resembles Neptune, and the other if it resembles Pluto. The latter is not thought probable. As we retreat from the Sun among

William H. Pickering

the larger planets, after passing Jupiter, we find that both the density and albedo tend to increase. The diameter, angular and linear as here given, is based on a density supposed identical with that of Neptune. Its diameter thus proves to be so large that it should present a clearly defined disk in our larger telescopes. It is so remote that we notice that its parallactic motion at opposition is nine times that of its real motion in its orbit. It is believed that the planet should certainly lie within 2° of its orbit north or south, and within 10° of its computed location. To facilitate finding it, I have indicated the orbit by giving the computed position of the planet 20 years ago, and also 20 years hence. The maximum perturbation of Uranus in 1912 is that given after allowing for the perturbing force of planet S in that year. The date of opposi- tion advances half a day every year.

Uranus has now been observed accurately through 147 years, or 1.75 revolutions. This interval is ufficient for it to have passed every un- known planet whose mean distance exceeds 33.3 units, at least once. No large planet therefore, unless extremely remote, can have failed to have left its mark on the orbit of Uranus.

PLANET T.

We now come to the rather interesting question, are there other, small, remote, dark planets analogous to Pluto, and in similar orbits, or on the other hand can we safely reject as illusory the little apparent perturba- tion following the large one in both Figures 4 and 5? If genuine we should naturally suppose that both of the small perturbations were caused by the same body, but this certainly cannot be the case, the diffi- culty being that both occur in the same longitude 350°. They cannot be due to a small dark star comparatively near at hand, nor to an outer planet moving nearly due north or south, because Neptune passed this same longitude in 1857 and showed no appreciable perturbation. They cannot be due to an unknown planet revolving in a period of one-half of that of Uranus, because in that case the perturbations would take the form of depressions instead of elevations. They must therefore be due to two distinct bodies. There can scarcely be any doubt at all of the existence of the one which perturbed Uranus in 1924. The observations of the earlier one shown in Figure 4 are so accordant that we should feel little doubt of it either were it not for the fact that its duration in longitude, as shown by the observations, certainly cannot exceed 120°, and might be as short as 80°. This would imply that it was very remote like P. This may of course be true, and we will call it provisionally planet T. If it were moving in a circular orbit, in the same period as P, Uranus would pass it once in 96 years, and 96 added to the date of the perturbation under discussion, 1841, brings us to the year 1937. An elliptical orbit might give us a somewhat longer or shorter interval, so we can make no definite statement, but we see that such a planet is pos- sible. It cannot, however, be very much more remote than P, or Uranus would have passed it a second time already. The sooner it appears again,

396 Planet P, Planets S and T

the more remote and massive it will be. Until it again perturbs Uranus, as far as that planet is concerned it will be impossible to set any lower limit to its distance from the Sun. This is about all that we can learn from Uranus, but Neptune will give us a little more information. By Figure 4 we see that Uranus received the maximum perturbation from T in 1841, in longitude 350°, and since T must have been about 11° be- hind it, 7 must have been in longitude 339°. It appears that Neptune in 1841 was only 25° behind that, in longitude 314°, and we shall assume now that it was overtaking T as rapidly as possible. It has not overtaken it as yet, however, sufficiently to show any perturbation of the Neptune curve. Neptune’s present longitude is 155°, and it has there- fore travelled 201° in ninety years. In case the conjunction of Neptune and T occurs in the present year, Neptune would surely have shown some perturbation by this time. Since it has not done so as yet, it seems that Neptune has not gained even 25° in ninety years. JT must therefore have moved more than 176° in that time, and its period must be less than 188 years, corresponding to a distance of 32.8 units. There is of course nothing impossible in the existence of a planet with a period so nearly identical with that of Neptune. Indeed its orbit might well lie between that of Uranus and Neptune, there is plenty of room for it there, and the only oppositon that we can raise to the idea is the fact that the base of the perturbation curve of Uranus appears to be too short. In conclusion we may say, therefore, that we can hardly as yet accept T as a real planet until it presents further evidence of its own existence, and that we must leave for another, or possibly a future generation of astronomers.

PLANET S.

In my paper on “The Orbits of the Comets of Short Period” (Popvu- LAR AsTRONOMY, 1928, 36, 280), I suggested, based on an isolated group of 4 comets, that they might perhaps be associated with a rather massive unknown planet that I designated as planet S. Based on the shortest aphelion distance of the group, 47.6, I suggested that its period would be 333 years. More accurately stated this should be 328 years. In my paper on “The Orbit of Uranus,” in PopuLar Astronomy, 1928, 36, 360, I pointed out that, with a period of 333 years starting with the max- imum perturbation which this planet would produce on Uranus in 1924, the previous one would fall near the summit of the large perturba- tion due to P in 1812. By means of the later planetary observations of Uranus now in our possession we may say that the small perturbation in Figure 5 is undoubted, and that the large perturbation in Figure 4 gives us therefore an interval of 112 years. Adopting this figure as the over- take period of Uranus and S, and 84 years as the period of Uranus, then the period of S turns out to be 336 years, and its corresponding distance 48.3 units. The resemblance of the two diverse determinations of the period and distance is at least suggestive. It is clear that S cannot be more remote than this distance, or its perturbation of Uranus would

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William H, Pickering 397

have appeared between the two maxima of Figure 4. If the distance of S is not about 48 units, then it must be less than 35, or its perturbation would have appeared between the years 1784 and 1812. That is to say it must be nearer than Pluto unless its orbit is very eccentric, in which case it might be a little more distant. There are, therefore, two possible explanations of what is almost certainly an unknown body of somewhat more than terrestrial dimensions. One is that it is moving in an orbit analogous to that of Pluto, and the other that it is moving in an orbit about 20 per cent larger. In the latter case it may be nearly ten times as massive as Pluto, in the former perhaps two or three times. Neptune since its discovery has been constantly ahead of S, and so can throw no light on its position.

The second maximum perturbation of Uranus is so recent, that S cannot have moved far in longitude from the position that it held at that time in 1924, 350° — 11° or 339°, using the same correcting angle that we have for P and T. If we adopt the greater distance, 48, that was confirmed by the comets, its mean annual motion will be 1°.10. If we adopt the maximum lesser distance 35, its mean annual motion will be 1°.74. Its present longitude, after seven years, on these two theories is therefore either 347° or a little over 351°, depending on how much shorter its mean distance is than 35 units. This, therefore, gives a com paratively narrow range over which it is necessary to search for it. There is no way of computing the latitude, and hence the declination, but as in the case of Pluto, I can give a hint with regard to it, and it is to be hoped that this time the hint will not be given weight zero. It is very certainly to the north of the ecliptic, and probably at some distance from it. This result is based on the northerly declination of Uranus as eiven in the Washington observations (Astronomical Journal, 1930, 40, 87) and during the last few years confirmed less markedly at Greenwich (Monthly Notices, 1929, 89, 261), and in a private letter from the Astronomer Royal as follows: for 1928.9 A8 0”.0, 1929.9 +-0".2, 1930.9 -0”.7. These last results he states are only provisional. The Washing- ton measures, also provisional, are in general for some reason about 1” higher than those of Greenwich.

Turning now to the comets, there are but four whose aphelion dis tances, ranging from 47.6 to 59.1 might connect them with planet S, and one of these is ruled out by the fact that the position of its aphelion on the celestial sphere is distant more than 50° from the great circle pass- ing approximately through the other three. Little weight therefore can be given to the information derived from this source, until more comets having approximately this aphelion distance arrive. Such comets are distinctly wanted. Such evidence as we have, however, indicates that the inclination of the orbit is 30°.5, or a little higher than halfway between that of Pluto and P. The node is 271°. If the planet is in longitude 347°, as we think most likely, the cometary aphelia would in- dicate that it is at present located 30° north of the ecliptic. Although its mass appears to be greater than that of Pluto, yet since we have no

398 Planet P, Planets S and T

satisfactory evidence as to the eccentricity, or the argument of the peri- helion of its orbit, we can only say that its brightness is probably about the same as that of that planet. The middle one of the three positions is thought to be the most probable location. The other two indicate the effect of giving the orbit a higher or a lower inclination, or of shifting the node. The line joining the three is perpendicular to the planet’s orbit.

TABLE II. LocATION OF THE PLANET S For 1932. Longitude Latitude R.A. Dec. 347 +20° ge 4i" +13°3 347 +-30° Egg aa -+22°4 347 +40° 22°04" +31°4

The positions are given for 1932.0. The declination is undoubtedly much more uncertain than the right ascension. I state this definitely, because in the case of Pluto, those who searched for it in 1919 extended their search unnecessarily far on both sides in right ascension, about 15°, yet always kept close to the ecliptic in declination, in spite of our statement that the inclination of the orbit was probably about 15°, that the planet had been in the south, but was now moving northerly, and was at present not far from the ecliptic. They thus missed the planet in their search at that time by less than two degrees in declination. Had I been informed of the search, I should have saved them from taking several unnecessary plates in right ascension, from searching north of the ecliptic in declination, and should have informed them that, since it was impossible to compute the declination, the latter was much more uncertain than the right ascension, and therefore they should look towards the south, whence the planet was believed to have come.

In general I should like to state very clearly that, when a search is be- ing made for any unknown body, be it planet or satellite, and it is not at once found, the computer should always be informed of the fact, and his advice asked for in that case. It would seem indeed fairly obvi- ous that, if the search is worth making at all, first, no time should be absolutely wasted upon it, and second, the computer would certainly know far more about his own computations than the searcher. Indeed it is only fair to the computer that, if his predictions are on trial, he should at least be warned of the fact. It would certainly be far better for both parties, for I know by experience how tiresome and dis- appointing it is to look over a stack of plates and find nothing. And yet, as in the case of Pluto, a single word from the computer might have turned failure into a brilliant success.

PRIVATE OBSERVATORY, MANDEVILLE, JAMAICA, B. W. I., Jury 8, 1931.

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la

The November Metcors in Maya and Méxican Tradition

THE NOVEMBER METEORS IN MAYA AND MEXICAN TRADITION

By STANSBURY HAGAR.

Before the arrival of the first Spaniards in Mexico, over 400 years ago, and probably much earlier, the Mexicans told of certain stars called Tzontemocque or [Falling Hairs, which fell from heaven to earth with the Lord of the Dead.’ Their fall was commemorated annually in the Quecholli festival, said to have been held towards the end of October. This festival, and the falling of the stars, was associated with the end of the world. As the ritual features of all the annual Mexican festivals

Figure 1. DESCENDING METEOR IN MEXICAN Copex BoraiA. (After Seler.)

were concerned with annual events, it seems evident that the fall of the Tzontemocque was also believed to occur each year. The Lord of the Dead governed the Festival of the Dead preceding the Quecholli, during which the spirits of the dead were supposed to return to earth from the land of Souls in the sky. No doubt they were believed to have been accompanied by their deity whose fall is mentioned in the ritual. On sheet 8, of the Mexican Vaticanus 3773, and in the Borgian and other codices, these Stars of the Falling Hairs, are depicted falling from the sky to earth accompanied by many other stars, further identified by the conventional star symbols beside them.

*Explanation of the Codex Telleriano Ramensts, fol. 4. v. and in Kingsbor- ough Mexican Antiquities, Vol. 6, pp. 101, 127, 130, Brasseur de Bourbourg in Landa, p. 37, note 3.

400 The November Meteors in Maya and Mexican Tradition

The Vaticanus Codex antedates the entrance of the first Spaniards into Mexico and depicts traditions much older than that date. From these facts it seems reasonably certain that the Tzontemocque were November meteors, whose falling hair referred to the fiery trails left behind them. The maximum fall of several meteor groups occurs in November. That of the Leonids, originating in Leo, occurred on Octo- ber 13 in 902 A.D., and October 24 in 1533,? so that, when the Spaniards entered Mexico in 1519, the fall of the Tzontemocque was celebrated on the day when these Leonid meteors attained their maximum fall, or very close to it. But the Mexicans seem to have distinguished between the different meteor groups, for they refer to the fall of a Tzontemoc on the day One Eagle which pertains to Taurus and would seem, therefore, to refer to Taurid meteors. The end of the world would naturally be associated with the memory of one of the great meteoric showers dur- ing November, when all the stars seemed to fall from the sky.

Ficure 2. TAurtp Meteor oN Maya ZoptAc AT ACANCEH, YUCATAN. (After Seler.)

(Downflying figure at right of top row.) ) I

At Acanceh in Yucatan a Maya Zodiac was placed on the stucco facade of a mound, probably long prior to the coming of the Spaniards. It was probably at least 600 years old when it was exhumed. On this Zodiac, which represents the signs in regular sequence, the position of Taurus is occupied by two panels, the lower of which represents the rattle of a snake. It is Tzabek, the Rattle Asterism, our Pleiades. The upper panel contains a downflying semi-human or ape-like figure. Be- side his tail are star symbols and above his head spears or arrows, im- plements of war, which, in the Quecholli festival, represent the end of

* Encyclopedia Britannica, Meteors; “Meteors,” Charles P. Olivier, 1925, p. 36. * Hagar in American Anthropologist, NS. Vol. 16, p. 89.

par tial of t the asc¢ hou

in r east

Sep to » nea

Planet Notes 401

the world, marked by the fall of the Tzontemocque.* This Maya figure also probably refers toa Taurid meteor emanating from Taurus in November when that asterism is near the meridian.

Some of the plains Indians of the United States were accustomed to mark the passing of time by drawing on a buffalo skin, some event that distinguished each winter. All these winter counts for the year 1833 depict a group of falling stars, interpreted as, ‘the stars fall,” “storm of stars,” “it rained stars,” “the stars moved around.” Especially note- worthy was the winter count of Chief Long Dog of the Yankton Dakotas.*

The end of the cycles of many peoples in November and their expec- tations of the destruction of the world at that time, was probably like- wise associated with the November meteors.° *Col. Garrick Mallery in Bureau of American Ethnology, Vol. 4, pp. 90-138. *See “New Materials for the History of Man,” by Robert Grant Haliburton,

Toronte h 1920.

PLANET NOTES FOR SEPTEMBER AND OCTOBER, 1931 By CLIFFORD E. SMITH.

The Sun will be moving southeast from the central part of Leo to the eastern part of Virgo. On September 23, at 6:00 Pr.m., C.S.T., the sun will cross the celes- tial equator which marks the beginning of fall. There will be two partial eclipses of the sun during this period; one, on September 12, will be visible in Alaska, and the other, on October 11, will be visible southwest of South America. The right ascension of the sun will change during this period from about 103 to about 14 hours, and the declination will change from about +9° to about —13°.

The phenomena of the Moon will occur as follows

Last Quarter Sent. Sat 1 aw. C.S.T. New Moon 11 “ 10 p.m. 3 First Quarter 18 “ 3 pM. Full Moon ae“ 2 PM. Last Quarter Oct. 4 2 P.M. New Moon 11 7 AM. First Quarter 18 3 A.M. Full Moon 26 “ SAM. Perigee Sept. 12 “ 11 a.m

Oct. 10 “ 10 p.m. Apogee Sept. 26 “ 9 p.m.

Oct. 23 “ 11 P.M.

On September 26 there will be a total eclipse of tl in most of the eastern hemisphere, but not in the western hemisphere excepting the eastern part of South America.

moon which will be visible

Mercury will be moving with an apparent western motion in eastern Leo until September 13; then its motion will become easterly, and it will move across Virgo to western Libra. At the beginning and end of this period its position will be near that of the sun, and during the middle of this period it will be a morning

402 Occultations

star of about zero magnitude, rising about an hour before the sun. Greatest elongation west will occur on September 21, and superior conjunction on Octo-

ber 18.

Venus will be near the sun in apparent position during the early part of this period since superior conjunction will occur on September 8, but at the end of this period it will be an evening star of magnitude about—3.5 setting about an hour after the sun. Its apparent motion will be direct.

Mars will be in the early evening sky but of even less interest than during July and August since its distance from the earth has been increasing, and since its apparent position will be approaching that of the sun. Mars will be moving from central Virgo to eastern Libra, and on the first of October it will set about two hours after the sun.

Jupiter will be a morning star in central Cancer of magnitude about —1.5, and its apparent motion in the sky will be direct. At the end of this period it will rise soon after midnight. Conjunction with the moon will occur on September 9 and on October 7.

Saturn will be in the evening sky in eastern Sagittarius, and it will be of about zero magnitude. Its apparent motion will be retrograde until September 21 and after that direct. Quadrature east of the sun will occur on October 11, and thus during the middle of October it will be on the meridian about 6:00p.m. Con- junction with the moon will occur on September 20 and on October 17.

Uranus will be in eastern Pisces and will be visible practically all night long during this period since opposition with the sun will occur on October 11. Its apparent motion in the sky will be retrograde. Conjunction with the moon will occur on September 28 and on October 25.

Neptune will be near the sun in apparent position. Conjunction with the sun will occur on October 29. OCCULTATIONS OccuLTATIONS VISIBLE IN LonGiITUDE +72° 30’, LatirupE +-42° 30’. (Contributed by the office of the American Ephemeris.) —_———1IM MERSION——— EMERSION

Green- Angle E Green- Angle E

Date wich from wich from 1931 Star Mag. oF i a b N wc: a b N Sept. 4 27 Tau 37 6 247 0.0 +2.8 27 7 25.1 —18 +0.8 278 4 28 Tau 5.2 6416 +08 +40 3 7 20.00 —2.7 —0.6 302

6 107 BAur 65 4 64 +0.2 +08 110 450.7 +06 +1.8 227

8 c Gem 55 7 20 —04 +01 133 7 45.0 +03 +2.2 233

22 56B.Cap 63 0206 —13 +19 17 118.8 —28 —0.7 296

24 50 Aqr 59 6256 —08 —05 66 7 320 —0.2 +01 224

26 20 Psc 5.6 4360 —09 +1.7 26 5 52.4 —18 0.0 250

27 44 Psc 61 0314 —05 +22 49 1 424 —10 +1.8 240 Oct. 1 n Tau 3.0 14216 —05 404 35 14598 +09 —2.4 310 2 x Tan 5.3 329.0 —04 +1.5 87 4 29.2 —0.2 +2.2 227

3 34 EB.tan 64 5 39 0.0 +25 45 6 46 —1.3 +08 283

6 A Cnc 5.9 6249 —03 +07 114 7 236 —0.4 +1.5 262

8 37 Leo 5.5 7 49.5 0.0 +0.9 105 8 46.0 —0.4 +0.4 298

27 27 Ari 64 5167 —18 +12 58 6 43.0 —1.7 +0.6 238

28 66 Ari 6.1 11 40 —08 +02 44 11548 +03 —22 295

29 x Tau 5.3 12 22 +09 —4.1 149 12 31.0 —13 41.5 204

Oc

Se

On

Occultations

403

OccuLTATIons VisIBLE 1N LoncitupE +91°, Laritupe +40°. IM MERSION— - ——EMERSION——— Green- Angle E Green- Angle E Date wich from wich from 1931 Star Mag. C.T a b N om a b N h m m m ° h I I m ° Sept. 4 104 B.Tau 5.5 5 338 135 $332 174 4 27 Tau a7 6 35. 340 6 42.0 327 17 b Sco 4.7 1 30.2 179 1 46 206 21 56 B.Cap 63 23 45.8 i a) J 0 29.6 - o< a 24 50 Aqr 59 6 77 —1.0 +06: 42 7 225 10 —0.2 241 26 20 Psc 5.6 4 24.5 - ee > ay ie o=. toe 27 44 Psc 6.1 0 21.6 0.0 +21 44 1 23.0 —0.5 +1.7 254 Oct. 1 i7 Tau 3.8 1257.2 —14 +10 39 13516 —0.2 —28 300 1 n Tau 3.0 1412.1 —06 —06 67 1513.4 +01 —1.5 277 2 x Tau 5.3 3 25.4 +03 41.5 69 4 22.4 0.0 +1.6 249 $ $54 B.Tau 64 5 65 +11 +31 16 5 38.6 14 —0.2 312 5 134 B.Gem 65 4 52.0 - .. 164 5 5.4 ee » ioe 6 A Cnc 5.9 6226 +03 +09 99 7 16.8 0.0 +1.0 275 27. 27 Ari 6.4 446.7 —09 +26 32 6 35 2 +0.7 255 28 ¢ Ari 48 1388 —0.7 41.0 111 2 18.4 +06 +28 192 28 «66 Ari 6.1 10 46.4 12 —04 68 11574 —06 —1.3 267 30° 354 B.Tau 64 13 52 —10 05 67 14 3.6 0.1 —2.2 301 OccuLTATIONS VISIBLE IN LoncitupE +120°, Latirupe +36°. Sept. 1 m™ Psc 5.6 13 47.2 —08 +30 10 1439.5 —1.5 —2.7 286 2 19 Ari 58 6 25 —0.2 +1.5 82 6 58.8 0.0 +2.2 213 21 A Ser 49 6359 —0.7 +02 46 7 44.9 10 —1.0 263 24 50 Agr ao «€§65 32 eo ~. aoe 6 13.8 . ae 24 182 B.Aqr 62 9276 —16 —1.4 94 10 22.1 0.2 +16 194 300 47 Ari 5.8 14 448 —1.5 29 16 = 15 21.5 0.1 —4.2 312 Oct. 1 16 Tau 5.4 12 36.7 i ae : 3 ga ao 1 17 Tau 3.8 12 0.9 21 +13 56 = 13 28.0 2.0 0.8 266 1 20 Tau 41 3 223 - .. 359 13 43.9 .. 328 1 23 Tau 43 13 3.3 —21 —3.2 124 14 13 19 +2.7 206 1 m Tau 3.0 13 44.6 16 —1.5 101 14 59.3 —1.4 0.3 234 5 v Gem 43 2552 2.0 +40 47 13 44.8 —1.9 3.9 335 25 171 B.Psc 63 2 84 0.6 +18 75 3123 —0.5 +23 213 28 «66 Ari 61 9542 —23 +03 77 11238 19 +0.5 239 30 354 B.Tau 6.4 12 28.1 18 —1.6 111 13 47.8 1.8 —03 250 The quantities in the columns a and b are given for the purpose of making these predictions useful for any place within 200 miles of the point indicated. The procedure is as follows: Subtract the longitude of the point given from

the longitude of the place in question; count, by the quantity under a for the star

latitude, 1

Greenwich C.T., nomenon at the place of observation. necessary to subtract five hours;

Date

1931 Sept. 21 24

Aug. 26 Sept. 21 24

ising b; apply th

VISIBLE AT OMAHA

Star » Sagittarii 50 Aquarii VISIBLE

x Capricorni A Sagittarii 182 B. Aquarii

e sum of th

Mag. ok ag ig h m 8 5 25 5.9 6 04 AT Mount HAMILTON 5.3 10 27 4.9 6 35 6.2 9 23

multiply the result, taking t to be obse e products and obtain the predicted Greenwich Civil To obtain Eastern Central Standard

signs into ac- with the

tne

rved; similarly,

with its proper sign, to the Time for the phe- Standard Time it is Time, six hours, etc. AND VICINITY. a h P m m ° +0.1 +-1.9 23 <i, 2 +1.8 29 AND VICINITY —),§ +2.0 31 —).6 +1.7 39 —1.5 +1.4 83

404 Comet Notes

The approximate times for observers within 300 miles of Omaha can be found by using the constants a and b, given in the table, according to the formula

G.C.T. = Predicted G.C.T. + aAdr + bAg,

AX and A¢ in this case being obtained by using the longitude (96°0) and latitude (41°3) of Omaha, and subtracting these, respectively, from the longitude and lati- tude of the place. For observers within 300 miles of Mount Hamilton, California, the same rule is followed using the longitude (121°7) and latitude (37°3) of Lick Observatory. Only disappearances are given.

Creighton University Observatory. Wx. Cretus Dovte, S.J.

COMET NOTES By G. VAN BIESBROECK.

Periopic CoMet ENCKE was due at perihelion in the beginning of June but it was then nearly in line with the sun so that it could not be seen. Its predicted course showed a rapid southerly motion in June which would have made it visible for southern observers. A telegram under date June 22, sent by C. D. Perrine, Director of the Cordoba Observatory in Argentina, brought the first information of the rediscovery. The comet was located there by Bobone on a photographic plate from which resulted the preliminary position:

1931 June 21.9328 U.T. a = 7" 35m4 5 = +8° 22’ Mag. 9. This position shows that Crommelin’s ephemeris (p. 351) requires the corrections: —69* in a and —48’ in 6. A slightly different ephemeris computed by L. Matkie- wicz of Pulkovo reduces these differences to —56* and —44’. These residuals show that the comet passed perihelion on 1931 June 2.9 and is therefore about one day ahead of the computed position in its orbit.

From now on the conditions of visibility improve rapidly for southern ob- servers but at the same time the brightness decreases so that this return, the thirty-seventh since this famous object was discovered, will be one of the most unfavorable possible. The brightness seems to be somewhat below the expected value which might account for the failure of earlier attempts at recovery last winter.

The great value of photographic exposures on the sky as a permanent record has been illustrated by a recent instance: last spring K. Reinmuth of the Heidel- berg Observatory found a cometary image on a plate exposed there on 1902 March 4. The object had not been noticed at the time the plate was taken; but the reality of the image was confirmed when Reinmuth recognized the same object on plates that had been taken the following day, 1902 March 5. It was moving slowly and appeared as a little spot about 1°5 in diameter with a faintly visible diffuse nucleus. The magnitude was estimated as 12. A faint appendage in position angle 220° suggested the presence of a tail. From the positions on the two successive nights B. Asplind has deduced a circular orbit indicating a large distance and a small inclination :

Node £2 318° 54°5

Incl. i = 8° 18

Radius of orbit 6.89 astr. units

Arg. of latitude 207° 37:4 on 1902 March 4.5 M.T. Berlin.

Comet Notes 405

A. C. D. Crommelin failed to identify this object with any of the older known comets, but L. E. Cunningham succeeded in establishing the correct identification. In Harvard Announcement Card 159 he shows that this image belongs to Comet 1925 II (ScHWASSMANN-WACHMANN) for which

= 322° 44’ i = 9 26' a = 6.43

according to the elements by Berman and Whipple. Their orbit corresponding to a period of 16 years represents the 1902 position within a couple of degrees and the daily motion fits exactly.

—

It will be remembered that this comet has shown very large fluctuations in brightness (see the illustrations in the April number of this year, p. 224) and that it seemed certain that, owing to the nearly circular shape of the orbit, this object might remain visible during its whole period of revolution around the sun. The 1902 observations confirm this expectation since at that time the comet was not far from aphelion which had come toward the end of 1900, but it seems that the Hei- delberg observer has caught the object in 1902 during one of its curious outbursts of light.

Comet 19306 (Beyer) is still under observation: on June 15 it was photo- graphed by M. Wolf with the Heidelberg reflector and estimated as 16™.5. Further observations by the writer on July 16 and 17 show it reduced to a hardly notice- able diffuse coma of magnitude 17 and about 2’ in diameter. It is doubtful whether further observations will be obtained of this comet which has now been followed for 21 months.

So far Comet 1913 III (Neuvymin), which, although faint, comes now under better conditions of visibility for northern observers, has not been recovered. It may be fainter than was expected or else the position may not be predicted closely enough. The search is being continued by the writer.

A telegram relayed through the Harvard Observatory in the afternoon of July 18 has brought the first information about an apparently new comet. The telegram read:

“Van Maanen telegraphs Nagata’s Comet photographically confirmed by Moore Mount Wilson July 17.685U.T. Right ascension 10°41", Declination +9° 48’.”

No indication was added as to the direction of motion nor was the brightness mentioned. The region is only visible for a short time after sunset and the object was therefore probably bright. In the evening of July 18 the comet was not found at the Yerkes Observatory. The sky was transparent but the view from the comet- seeker was intercepted by the big dome, the field was hidden by trees for the Bruce telescope so the search was made first with a binocular and next with the 3-inch finder of the 12-inch refractor. The nearby crescent of the moon added to the difficulty. It is to be hoped that other observers have been more successful. Williams Bay, Wisconsin, July 19, 1931. ADDENDUM.

Three additional positions of Nagata’s Comet have been received from Mount Wilson by telegraph, as follows:

Date R.A. Dec. Authority 1931 oe ni July 18.1792 10 40 44.7 +9 51 03 Nicholson and Moore 19.1861 10 45 06.0 +9 54 47 Nicholson and Moore 20.1790 10 49 22.3 +9 58 12 Nicholson and Ross

Tail four degrees. Magnitude 9 (Aitken).

406 Meteor Notes

METEOR NOTES

By CHARLES P. OLIVIER.

The writer is on vacation and has left directions at the Flower Observatory that observations were not to be forwarded to him. Hence the time for writing the usual Meteor Notes has arrived, and the only observations here are a few that were enclosed in private letters. These will be briefly mentioned. Through Mr. R. A. McIntosh, a brief résumé of the recent work of our new member, Mr. Geddes, of New Zealand has been received. His detailed results will appear later. He observed 79 meteors on 10 nights in February, 108 on 6 nights in March, 212 on 9 nights in April, and 58 on 4 nights in May. This is an excellent record of 457 meteors in four months. They are particularly valuable as coming from the Southern Hemisphere.

Through our colleague, Professor M. Dartayet of the La Plata Observatory, we received the detailed results of the work of Mr. J. L. Munoz of Lomas de Zamora, Argentina. The tabular results appear here; the radiants will be worked up later. From the U. S. Weather Bureau come reports of fireballs on May 3, 5, 6, and 12 from ships at sea. All the other observations received at Flower Ob- servatory during the past month or two will have to await future discussion, as the writer has not seen them.

The University of Pennsylvania has authorized the securing of the services of a special assistant for a year to help reduce back observations, largely those of the A.M.S. This assistant will begin in September, and it is hoped that rapid progress will be made. Also that it will be more possible to keep up with current reports.

Recently Harvard College Observatory has announced the establishment for a year of two regularly equipped meteor stations in Arizona, to be manned by professional astronomers devoting all their time to meteoric research. Professor C. C. Wylie has for some years carried on very successful researches on fireballs and meteorites in the Middle West, as has Dr. W. J. Fisher in New Zealand. With all this increase in interest in meteoric astronomy we do not wish the A.M.S. to fall behind. But in order that our results shall show up well in comparison, it is essential that more of our members work harder. Especially they should acquaint themselves with the nature of the problems that need solution, and try to keep up at least partly with what others are doing. In other words, study as well as night work is an essential for a man who hopes to do the most valuable work. It is quite true that we welcome and need men and women who are good observers only—our central office will gladly reduce their results. But even for them a slight knowledge of what they are about and to what their observations may lead will be most helpful.

Through the daily press, magazine articles, and over the radio much publicity has been given to meteors of late. This should lead to an increasing number of people sending in usable observations of fireballs, as well as of the few showers that the casually interested person might turn his attention to. As such good results were obtained in places favored with clear skies in both 1928 and 1930 on the Leonids, there is good hope for increasing showers during the next two to four Novembers. It would be a great pity for such a shower as that of 1833 or 1866 to appear and be inadequately observed. But proper observing cannot be done without a little preparation and practice. This is one good reason for the

Meteor Notes 407

campaigns of the last few years in each August and November. In any case, the more intelligent people become interested in meteoric astronomy, the faster it will progress.

As to our regular members, those in the same state or adjoining states, par- ticularly when 100 or less miles apart, are urged to communicate with one another and undertake simultaneous programs. This is far the best way to stimulate both accuracy and interest, as reductions show at once the points where improvement are most needed.

Joaguin L. Munoz, LomAs pe ZAMorA, ARGENTINA.

1931 Began Ended Total Meteors Factor Rate Cor. Rate Jan. 15 22 :20 24 :00 100 9 0.9 5.4 6.0 18 22:17 24:19 122 16 1.0 7.9 7.9 Feb. 10 21:58 23:25 87 10 1.0 6.9 6.9 11 22:33 23 :50 99 19 1.0 12.3 12.3 12 21:33 23:37 104 26 1.0 15.0 15.0 13 22 :07 22 :56 49 15 0.8 19.5 24.4

The time used in the above is as of 3 hours west and is counted from mid-

night.

The names of several new members will appear in the next Meteor Notes. Four theoretical papers on meteors have been finished by the staff of Flower Observatory recently and await publication. Two are independent investigations of the errors made and the accuracy to be expected in Schaeberle’s Method for

computing heights. The paths of several fireballs are under investigation and will be finished in the relatively near future.

Chesterbrook Farm, Rosslyn, Virginia, 1931 July 15. The Fall of a Large Meteorite On June 10, 1931, press reports carried the account of a mysterious shock, generally attributed to a meteor, which rocked northern Ohio The following is from a Michigan daily:

about 2:00 a.m.

A meteor measuring more than ten feet in diameter stru near here early today with terrific force, shattering windows in nearby houses and frightening residents from their homes.

Sleepers tumbled from their beds in alarm as the comet struck with a resounding roar. Buildings in the near vicinity were rocked and window panes were shattered. The intonation was heard for mil leading frightened inhabitants to believe an explosion had occurred. The meteor buried itself twelve feet into the ground, a quarter mile north of town. A few feet over and it would have crashed into the concrete pavement.

Mr. Stuart H. Perry, of Adrian, Michigan, owner of the smaller Paragould meteorite, made a personal investigation which definitely showed the incident must have been caused by a cache of high explosive rather than by a meteor. No meteor was seen by persons outdoors, and a large meteor should have made a brilliant light conspicuous at a distance of more than a hundred miles. The report was a single sharp explosion, without the following roar characteristic of a meteor. Finally, oil well drillers said the force of the shock indicated about 30 quarts of nitroglycerine might have been used.

Although this was evidently due to high explosive, it is worth while to con- sider the probable effect of the fall of a meteorite “measuring more than ten feet in diameter.” The heights of disappearance have been computed for meteors of various sizes as: for ordinary shooting stars, 55 miles; for fireballs, 35 miles or lower; where meteorites have been recovered, an average of fourteen miles; for

408 Monthly Report of the American Association

the Paragould meteorite, the largest observed, five miles. This suggests that for a meteor several times as large as the Paragould, the cap of incandescent gas giving the fireball appearance would accompany the meteor to the surface of the earth. Observation and calculation agree that for the ordinary meteorites ob- served to strike, the velocity of striking is less than the velocity of sound through air. For large meteorites weighing many tons, the case is different.

For an iron sphere weighing 125 tons and entering the earth’s atmosphere with a velocity of ten miles per second (near the minimum possible), Professor Moulton calculated that the striking velocity after a vertical fall would be 3.8 miles per second. At this speed, the kinetic energy is nearly three times the energy of an equal weight of nitroglycerine. As this tremendous amount of energy must be converted into heat almost instantly, it appears that much of the meteorite, and a certain amount of rock and earth would be vaporized with such suddenness as to cause a violent explosion, more violent than an equal weight of nitroglycerine.

Professor Moulton applied this result to Meteor Crater, deducing that the mass was probably much smaller than previous estimates which failed to take account of the enormous kinetic energy; and also that the main mass was prob- ably entirely vaporized at the time of striking. He believes it is useless to con- tinue mining operations in search of the “main body.”

If the meteoric theory is correct, the same reasoning can be applied to the Siberian incident of June 30, 1908. From a discussion of the air waves as record- ed in England and other information, Whipple accepts 130 tons as a reasonable estimate of the weight of the meteor. A single iron sphere seven feet in diameter would be of about the right order of weight. If, as is possible, his estimate of velocity is too high, the weight should be correspondingly increased. On this assumption, the hot gas which spread with explosive force was from the vaporized meteorites. The air driven out from in front of the meteor was a minor item.

wit ' C..C. Wri. University of Iowa, July 19, 1931.

VARIABLE STARS

Monthly Report of the American Association of Variable Star Observers for May and June, 1931

Herewith is the usual double, summer report, representing the work of 44 ob- servers on 413 variables, totalling 3752 observations. New contributors include Charles T. Vorhies of Tucson, Arizona, who has been observing under the guid- ance of Mr. Jos. Meek, C. Mennellay of Naples, Italy, who has been tutored by Professor A. Bemporad, and Mr. A. B. Aldwell of San Francisco, California. Fr. McNally, of Georgetown College Observatory, and Sig. Ancarani, of Faenza, Italy, also return to the ranks of active observers after an interval of several months. Mr. R. N. Buckstaff, of Oshkosh, Wisconsin, reports that he took unto himself a mate on J.D. 2426523, and that the Association thereby gains a prospective observer.

The Chart Curator, Mrs. Helen S. Hogg, who has been at Mount Holyoke College Observatory for the past year substituting for our Miss Farnsworth, will after August 1 take up her residence in Victoria, B. C., Canada, where Dr. H. S. Hogg has recently been appointed a member of the staff of the Astrophysical Ob-

VARIABLE STAR OBSERVATIONS RECEIVED Durinc May AND JUNE, April 0 = J.D. 2426432; May 0 = J.D. 2426462;

J.D.Est.Obs. J.D.Est.Obs.

V Sct pat 39 406 10.8 Bl S Sci 001032 410[11.1 Bl X AND 001046 396[12.9 Rs 474 8.3 Me 485 9.1Fd T AND 001726 488 13.2 Pt 505[12.3 Gy Tt Cas 001755 423 87L 438 10.3 Th 439 9.4 Ah 440 9.4 Ah 440 9.0Jo 440 10.2 Th 442 10.4L 443 9.5 Jo 444 10.5 Th 444 9.7 Ah 445 10.8 Pt 446 10.0 Jo 450 10.7 Jo 450 452 454

10.2 Th 10.6 L

10.8 Jo 10.6 Th

R ANpD “001838 477 11.6 Fd 479 11.2 Gy

48s 11.4 Fd 488 11. 4 ‘* t 505 11.9 Gy

S Tuc

001862 407 [13.2 En 410[12.4 Bl

10.4 Me

of Variable Star Observers

T PHE 002546 9.3 Bl 9.4 En 418 9.5 Bl 442 98 Bl W Sci 0028 33 410 13.1 Bl Y Cep 003179 450 10.4 Pc U Cas 004047

406 407

[

V AND

004435

486 10.2 L x Sch

004746a 485[12.1 I'd Cas 004746b 485 10.6 Fd 488 10.5 Pt

W Cas 004958 439 9.5 Ah 440 8.9Jo 440 9.6 Ah 443 9.0Jo 444 95Ah 445 91Pt 446 9.0Jo 450 9.2Jo 452 99 BL 456 9.7 Jo 485 9.7 Fd 488 10.6 Pt U Tuc 005 175 406 8.7 Bl 407 89 En 411 8&7 Ht 414 83En 415 86 Ht 418 8.5 Bl 421 8.5 Ht 421 86En 436 8&8 Ht 440 8.7 Sl 440 8.7 Dr 442 9.1 Bl

J.D.Est.Obs. U Tuc 005475 8.9 Sl 8.9 Dr 9.7 Bl 9.2 Ht 8.8 Dr 9.5581 U Sci 010630 410 96Bl U ANpD 010940 423 128 L UZ Anpb 011041 423 14.0L S Cas 011272 474[12.5 Me

RZ

448 450

Ringer

45

45: 455 455

021258 440 8.4Jo 440

8.8 Ah

J.D.Est.Obs.

T Per 021258 443 84Jo 445 8.7 Pt 446 8.5 Jo 449 87 Me 450 8.6 Jo 450 9.0 BL 452 88BL Z Crp 021281 447{13.1 Pe o CET O02T 403 383 9.4Mn 407 8.9 En 438 5.9SI S PER 021558 440 8.4 Jo 440 9.5 Ah 443 &3To 445 9.6 Pt 446 83Jo 449 9.5 Me 450 94Bg 450 84 Jo 450 10.0 BL 452 9.7 BL 479 9.7 Sz 488 95Pt RR Pe 022150 423[13.7 L R For 410 85BIl 442 8.5Bl 451 9.0 Bl RR Cep 022980 447 13.0 Pc R Tri 023133 505 7.1 Gy W PER 024356 436 9.3Ch 440 8&8 Jo 443 88 Jo 445 87 Pt 446 8&7]Jo 449 9.2 Me 450 9.0Jo 450. 9.1 Bg 467 9.5Jo 471 98Jo 474 9.5 Mc 488 8.8 Pt

409

1931.

June 0 = J.D. 2426493.

J.D.Est.Obs.

R Hor

O 408 410 411 415 415 420 421 436 440

440

442 447 450 451 453 467

T 410

41] 415 415 440 450 452 467

25050 10.1 En 9.5 Bl 9.8 Ht 9.5 Ht 9.5 En 8.7 En 9.2 Ht 7.3 Ht 7.0 Dr 6.8 S] 6.9 Bl 6.4 Sl 6.2 Dr 6.4 Bl 6.1 Ht 5.8 Dr Hor 25751 12.5 Bl 12.9 Ht 12.9 Ht 12 21 P 13.3 Dr 13.1 Ds Lyte 3 Dr

x Cor

0?

a9 3/0

425

450 450 451 488

R

MOL 10.4L

9.7 Pt

10.5 Jo 10.9 Me 10.6 To 10.5 BL 10.4 Me

90 Pt

PER

0323

423 442 443 445 446 448 454 458

Nov

325355

10.0 L

9.0L 9.3 Jo 8.7 Pt 9.1 Jo 9.0 To 921 9.0 Jo PER

032443

445|

uy

13.2 Pt 06

CIP

J.D.Est.Obs.

U Eri 034625 408 10.5 En 413 10.6 En 415 10.6 En 420 10.8 En 440 11.8 Dr T Ert 035124 8.8 En 8.6 En 8.5 En 8.0 En 8.0 Dr 8.9 Dr W Eri 040725 440 10.2 Dr 10.3 Dr W Tat 042215 425 10.3 L 440 9.6 To 442 10.1 L 143 95To 445 10.1 Pt 446 93 To 450 94Jo 454 10.1 L Tr Cam 043065

408 413 415 420 440 467

467

423 144L

441 12.3 Jo

442 142L

445 14.0 Pt i3./ Pe

447

450 12.0 Jo 454 13.7 L 460[12.2 An 467 471 11.8 Jo 487

12.0 Jo

5a Se S Ret

043163

440 11.2 Dr

450 11.2 Dr 467 11.2 Dr RX Tau 043208

443[12.0 L

R Ret

043263 8.7 En 8.4 Bl 8.4 Ht 8.8 En 9.0 Ht 9.6 Ht

408 410 411 413 415 421

410

Monthly Report of the American Association

VARIABLE STAR OBSERVATIONS RECEIVED DuriING MAy AND JUNE, 1931.

J.D.Est.Obs.

R Ret 043263 436 10.4 Ht 437 10.4 En 440 10.1 Dr 440 10.2 Sl 442 98 Bl 449 10.9 En 450 10.5 Dr 451 10.7 Bl 453 11.2 Ht 455 11.0S1 467 11.5 Dr X CAM 043274 9.5L 442 10.6L 445 11.3 Pt 447 10.7 Pc 454 11.6L 487 12.1L

R Dor

423

S

~ Is he

nN

%

rar

— bent Wwe OS it Awumwua

450 451 453 455 467 Dr R CAE 013738 408 11.9 En 410 12.2 Bl 411 12.1 Ht 413 12.0 En 437[12.0 En 440 13.2 Dr 453[12.0 Ht 467 [13.4 Dr Rm Fic 044349 08 82En 410 86Bl 411 86Ht 413. 8.2En 415 86Ht 421 84Ht

_

=

ro) ALUWUMNSDUWNIns Urry 14S € Ube ty Ww Ota BRB NWN UID

ao

J.D.Est.Obs.

R Pic 044349 422 82En 436 437 440 442 449 450 451 453 467 V Tau 044617 9.1 Pt 8.9 Ch 91B R Ort 045307 425 11.8L 443 12.0L 447 11.8 Ch R Lep

04551. 380 398 425 440 447 449 456

ININNNNNN mONNN WO — — cr

=. 1)

As

445 447 449

~S a aa

~

—_—

—

TUNANN RrAMUW

BnrsaS

ss

aN —_) 2

—

6.2 S] V Ort 050003 443 13.5L

T Lep

050022 408 8&8En 410 88 Bil 413 91En 422 10.5 En 437 10.4 En 442 10.1 Bl 449 11.2En 451 10.4 Bl S Pic 050848

9.8 En

8.7 Bl

9.3 Ht

9.6 Ht

9.9 En

9.7 Ht 2 10.0 En 10.3 Ht 10.6 En 9.8 Dr 10.0 Bl 11.1 En 10.4 Dr 10.1 Bl

J.D.Est.Obs.

S Pic 050848 453 10.4 Ht R Aur 050953 12.8 Pt 13.0 Ch 13.2 Pt T Pic 051247 10.6 En 10.1 Bl 10.0 Ht 10.0 Ht 9.3 En 9.9 Ht 9.2 En 10.0 Ht 9.4 En 9.6 Dr 10.0 Bl 9.5 En 9.6 Dr 10.1 Bl

445 447 475

410 410 411 415 415 421 422 436 438 440 442 449 450

Jt

> uv AS 3 > p=" G

415 9.7 En 421 10.3 Ht 2 10.0En 438 10.5 En 10.7 Dr 10.8 Bl 10.9 Dr 1 10.9 Bl 453 11.0 Ht S Aur 052034 9.0 Ch 9.0 Jo 9.0 Jo 8.3 Pt 9.0 Be

437 441 445 445 447 447 447 448 450 9.2Jo 450

450 92BL 451 452 455 465

J.D.Est.Obs.

S Aur 052034 466 88Fd 466 8.6Jo 469 89 Jo 475 8.6L W Avr 052036 Oz. 8.9L 9.3 Jo 931, 8.9 Pt 9.2 Jo 9.4 Be 9.4An 9.6 Ch 9.3 Jo 96 Sf 9.0 Jo 9.5 Mg 9.3L 95B 9.9 Sf 9.8 Jo 407 98L 9.6 Jo

423 432 441 442 445 445 447 447 447

—)

445 446 446 447 448 450 450 454 S Cam 053068 9.6 Pc 9.2 Jo 9.0 Jo 9.7 BL 9.8 BL 9.0 Jo 10.0 BL 10.1 BL

447 447 450 450 452 453 455

461

S Cam 053068 10.1 BL 10.2 BL 10.3 BL 9.5 Jo 10.0 Pt

9.3 Bg

462 465 468 471 475 479

490 10.7 BL RR Tau 053326 423 13.0L 425 12.9L 426 13.1L 428 12.7L 431 13.1L 442 113 L 443 12.1L 445 12.6L 446 12.7L 447 12.9L 450 11.6L 454[12.1 L 461 12.5L .V Aur 053337 447[12.8 Ch 475[12.0I U Aur 053531 423 771L 431 7.4L 433 7.7 Ah 434 7.7 Ah 435 7.7 Ah 439 7.8Ah 440 7.7 Ah 442 7.6L 444 78Ah 445 80Pt 447 7.5Ch 448 7.9 Ah 450 7.2B 450 7.8Jo 450 8.0Sf 452 7.7Jo 454 79L 456 8.1Ah 465 84Sf 466 85Jo 469 84]Jo 471 83Jo 475 88&L SU Tau 054319

423 12.0L 425 12.0L 428 12.1L 436 10.8 Ch 442 12.0L

J.D.Est.Obs. J.D.Est.Obs.

SU Tau 054319 445 12.0L 445 11.5B 445 11.7 Pt 447 11.7 Pc 11.6 Ch 11.9L 11.7 L 11.4 Pe 11.4 Ch 11.6 Mg 11.0 Pt af be 11.8L 2 110 Pe 6 11.6 Pt y faa i = (oi.

443 13.3 L 454 13.1L RU Tau 054615c 423 11.9L 443 12.4L 447 12.5Ch 454 119L R Cor 054620 407[12.4 En 411[13.0 Bl 415[13.0 Ht 415[13.0 En 421[13.0 Ht 422[12.4 En 438[13.0 En 442[13.0 Bl 449[13.0 En 453[13.0 Ht a Or! 054907 0.3 SI 0.3 SI 0.2 S1 0.1 Sl

443 447 450 452

of Variable Star Observers

——————— ae

VARIABLE STAR OBSERVATIONS RECEIVED DURING

J.D.Est.Obs.

U Ort 054920a 439 9.7 Ah 441 9.3 Sl 445 9.4Sl 445 10.2 Pt 446 9.9 Jo 447 10.0 Ch 448 10.0 Jo 450 10.2 Jo 450 10.1 Wd 452 10.2 Sl 459 10.4 Wd 465 10.5 Wd Z AUR 055353 445 10.2 Pt 447 10.2 Pt 449 10.2 Pt 449 9.7 Me 10.2 Pt 9.7 Me 10.3 Pt 9.6 Me 2 10.2 Pt 2 98Pt 6 10.1 Fd 6 10.0 Pt 9.7 Me 3 10.3 Pt 10.2 Mc 10.5 Mec 10.2 Fd 10.2 L. 10.5 Mc 10.4 Mc 479 10.3 L 480 10.2 L 481 10.5L 494 10.2 L 498 10.3 L 561 10.3 L R Oct 055686 411 12.4 Bl 415[12.0 Ht pation

rate 490

476 478

7 mw ww —_ — dt o< —

=]

SOonhku Of ox

ts - + NO — NNN YN _

— W

J.D.Est.Obs. X AuR 060450 10.5 Pt 10.7 Sf 10.7 Pe 11.1 Ch 11L.2Sf 454 11.4L 462 11.6B 467 12.1L

445 447 447 451 452

475 13.6 L V Aur 061647

423 10.2L

442 10.3 L

446 10.1 Ch

450 9.0 Bg

453 9.2Bg

453 99B

454 99L

459 91Be

473 9.7Mec

478 94B

479 86Bg

486 9.1L V Mon 061702

445 12.4 Pt AG Aur 062047

425 10.0L

442 92L

454 94L

467 9.4L

486 98L U Lyn 063159

449 10.6B R Mon 063308

447 12.6Ch 451 12.5 Ch Nov Pic 063462

407 8.5En 410 85En 411 83Ht 415 83Ht 421 84Ht 422 85En 427 84En 438 8&5En 449 86En 453 83 Ht 454 84En S Lyn 063558

425 14.6L 445 13.8 Pt 467 14.1L

J.D.Est.Obs.

S Lyn 063558 475 13.2 Pt X GEM 064030 449 12.8B

449 12.7 Me 451 12.7 Me 465 13.0 Bw 467 13.0 Me 471 12.8 Me Y Mon 065111 425 13.1L 437 13.2 Ch 443 13.7 L 445 13.4 Ch 449 13.7B 450 13.6 Be 453 13.6 Bg X Mon 065208 425 7.2L 440 7.3Dr 443 7.3L 447 78TEf 450 7.5Dr 453 7.9 Tf 454 7.7L 457 84Tf 459 85Tf R Lyn 065355 425 13.3 L 443 13.2L 449 13.7B RS Gem 065530 466 11.0 Ma Z CMA O650IT

440 10.2 SI 447 10.3 Sl 455 10.4Sl V CMr 070109 451[12.5 Ws R Gem 070122a 439 10.2 Ah 441 10.5Jo 445 10.5 Jo 445 10.8 Pt 445 10.0Ch 446 10.6 Jo 449 10.2 Me 450 10.7 Jo 450 10.3 Bg 450 10.3 Wd 453 10.8 Jo

J.D.Est.Obs. R Gem 070122a

456 10.5 Wd 459 10.6 Wd 459 10.1 Bg 461 10.7 Wd 462 10.7 Wd 462 104B

10.9 Wd

11.0 Jo

10.4 Me

10.9 Wd

10.5 Al

465 466 467 467 468 471 475

479

= A

3 = Van Pind DYiZoOoOn YG)

— bh

=“ to wn v2

oO 20

[2 02 02 CO GO DO 50 Un ST CO BOND UI

x»

I 8.6 Me 8.4 Ws 8.6 Jo 8.4L 8.3B 8.6 Sf 8.4 Ws 8.4 Jo 8.5 Me 8.2 Jo

R Vou

070772

410 10.4 En

411 10.2 Ht

415 10.0 Ht

415 10.7 En

421 10.1 Ht

422 10.9 En

438 10.9 En

440 99Dr

449 11.3 En

453 10.8 Ht

456 11.6 En

411 May AND JuNE, 1931. J.D.Est.Obs. J.D.Est.Obs. L. Pup Z Pup 071044 072820b 440 5.4Dr 38 12.7 En 440 5.2S1 449[12.1 En 448 5.2Sl S Vo. 449 5.8Dr 073173 450 5.6Dr 410 11.8En 456 5.4S1 411 116Ht 467 5.2Dr 411 12.0Bl RR Mon 415 11.4Ht 071201 415 12.2 En 446 11.0Ch 421 114Ht 447 11.4S£ 422 12.2En 449 10.9Me 438 12.2En 451 10.9Me 440 12.1 Dr 451 10.8GC 442 11.9Bl 452 110GC 449 11.8 En 452 10.6Sf 451 11.8Bl 461 10.0GC 453 11.4Ht 465 98Sf 456 12.2En 467 7 Me U CM 470 9.7 Me 073508 V Gem 425 11.4L 071713 443 12.4L 425 Mts 445 12.1 Pt 443 8.1L 445 12.0 Ch 445 8&3 Pt 449 12.5B 445 83Ch 450 12.5 Bg 449 84Me 454 12.9L 451 85GC 475 12.5 Pt 452 84GC 480 13.3 Bg 454 8.6L S GEM 457 86B 073723 461 9.0GC 446[13.6 Fd 467 9.2Vh 473[13.5 Mg 467 9.2 Me W Pup 474 96Vh 174241 475 9.0Pt 410 8.2En 477 97B 411 88Ht S CM 411 8.5 Bl 072708 415 8.0Ht 437 119Ch 417 8.6 En 438 11.9Ke 421 8.7 Ht 443 120Ke 422 87En 445 118Pt 428 9.0Ht 447 11.7Pc 438 9.4En 449 11.5Ke 440 9.5Dr 466 10.6Fd 449 10.3 En 470 11.2B 452 10.5 Bl

475 10.3 Fd 475 11.0 Pt T CM1 072811 445[13.2 Ch 473 12.0 Mg Z Pup 072820b 410 12.0 En 415 12.4En 422 12.4 En

453 10.6 Ht 456 10.7 En T Gem 074323 438 13.7 Ke 446[13.1 Pc 446 13.51} +y

412

Monthly Report of the American Association

VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND JuNE, 1931.

J.D.Est.Obs.

T Gem 074323 473 13.1Mg 480[13.1 Bw 489[13.1 Bw U Pup 075612 447 11.4Ch R Cnc 081112 433 8.2 Ah 434 8.2Ah 435 8.1 Ah 438 7.8Ch 439 440 7 441 7. 443 7. 444 7 445 7.11] 446 69Jo 447 6.9 Pc 448 7.3 Ah 450 451 6.9Ws 452 7.0Ch 452 69Wd 453 6.6 Jo 456 6.9 Ah

457 69B

459 6.9Wd 462 7.0Wd 464 7.1 Ah 465 6.7 Ws 465 7.0Wd

467 7.0Wd 473 7.4Mc 475 7.0 Pt 478 7.0B 480 7.0 Wd 489 7.2Wd V Cnc 081617

425 9.7L 434 10.8 Ah 438 10.6 Ke 439 10.8 Ah 443 11.8 Ch 443 10.4 Ke 443 11.4L 445 11.6 Pt 446 11.2 Gy 449 11.5 Me 449 11.6 Ke 451 11.2 Gy 465 12.0 Wd 470 120B 472 123L 475 12.4Pt 487 12.4B

J.D.Est.Obs. RT Hya 082405

438 84Th

439 81Ke 440 84Th 442 7.5Mp 444 82Th 444 8.1Ke 445 78Pt 447 9.0Jo 448 8.0Th 449 7.9 Ke 449 7.8Me 451 7.7 Me 452 79Th 453 7.5 Bg 457 8.0Th 466 7.6 Me 466 7.8Th 472 7.8Th 474 7.3 Mp 475 7.6 Pt R CHa 082476 410 12.8 En 411 12.5 Ht 411 12.5 Bl 415 12.5 Ht 421 12.6 Ht 438[12.4 En 440 13.3 SI 442[12.6 Bl 449/12.4 En 453[12.6 Ht U Cnc 083019 44. 3 14.3 L

495/12.9 Bw X UMA 083350

439 13.5 Ke

444 13.3 Ke

449 12.5 Ke

449 128 Me

450 12.8 Be

451 12.5 Me

467 10.7 Me

470 10.5B 470 10.5 Me 471 10.8 Jo 472 10.0 Vh 475 10.1 Pt 478 10.3B

479 10.3 Bg 9.5 Jo

9.4]Jo

J.D.Est.Obs. S Hya 084803

443 11.4Ch

445 11.4 Pt

447 11.5Jo

450 10.8 Bg

451 11.0Jo

459 10.3 Bg

467 9.6Jo

467 9.5B

467 9.6 Jo

467 9.6 Me

471 9.4Jo

475 86Fd

475 8.9 Pt

477 9.0B T Hya 085008

425 9.0L

443 9.9L

443 10.1 Ch

444 10.5 Jo

445 10.2 Pt

448 10.5 Jo

452 11.0 Jo

469 11.2 Mg

472 11.4L 478 11.8B T Cne 085120 441 89Jo 443 88 Jo 443 9.4Ch 445 9.0 Pt 446 88Jo 9.8 BL 450 8&7 Jo 1 9.1 Me 2 99 BL 3 8.6 Jo 5 9.6 BL 461 O8BL 2 99 BL 465 9.7 BL 9.8 BL 475 84Pt 476 96 BL 478 95 BL 9.3 BL a Vx 090031 411 [u Bl 442 [t Bl V UMaA 090151 426 10.8 L 439 10.6 Ke 442 10.6L 444 10.2 Ke 449 10.8 Ke

J.D.Est.Obs.

V UMA 090151 450 10.4 Sf 465 10.4 Sf 470 10.3 B 471 10.2 L 473 10.7 Mc 474 10.6 Mc 476 10.8 Mc 476 10.3 Sf 478 10.8 Mc 485 10.1B 487 10.2 L 495 10.0Sf 506 9.9 Sf U Cnc

090425 426 14.1 439 443 443 443 444 449 450 467 472 477 483[12. Mp 494 12.4 Al

RX UMa

090567 426 10.8 L 442 99L 471 10.4L 487 10.8 L

RW Car

091868 410 12.8 En 411 12.6 Ht 411 8 Bl 415 It 416 ‘n 421 It 422 ‘n 427 n 437 n 442 31 443 10.9 Dr 450 10.7 En 451 10.6 Bl 453 10.4 Ht 456 11.0 En

Y VEL

092551 411 13.5 Bl 415[12.9 Ht 421[12.9 Ht 422[12.4 En 437[12.4 En

ARO > Oo oO

Dio Who?

he) bet et at bd GCOnm

ww UA

ht — bo

bo II WW WWW WHYS:

NS WL

= SRN NNN

Zt 8 E At a8: OF 8E OT 9

J.D.Est.Obs. Y VEL 092551

442 13.2 Bl 448 14.6 Dr 448 14.5 Dw 450[12.9 En 451 13.4 Bl 456[12.9 En R Car 092062 410 99En 411 9.7 Ht 411 99BI 415 98Ht 417 99En 421 9.9 Ht 422 9.7 En

9.7 En

9.5 Dr

9.7 Si

442 10.0 Bl

448 9.3 SI

450 9.7 En

9.8 BI

10.0 Ht

9.4 Dr

9.2 Sl

9.7 En

X Hya 003014

440 10.3 Jo

443 11.0 Ch

444 10.4 Jo

445 11.1 Pt

446 11.3 Gy

446 10.5 Jo

451 11.3

awe

ALL ADL

wmyuvinnvt

~ >

093934 434 10.9 Ah 439 10.7 Ah 439 10.8 Ke 440 10.8 Ah 441 10.4Jo 443 10.7 Ch 443 10.7 Ke 444 10.6 Ah 445 10.8 Pt 446 10.2 Jo 446 10.1 Gy 447 10.4 Fd 449 9.6 Me 450 9.7Jo

J.D.Est.Obs.

R LM 093934 450 9.9 Ke 453 9.6Jo 466 9.5 Fd 467 86Me 468 8.5Al 469 82Jo 471 8&.1Jo 473 9.1 Ah 475 84Pt 475 81Fd 479 8.0Sz 479 8.6 Gy 494 7.7 Al 495 7.5Jo 498 7.8 Gy RR Hya 094023 413[12.8 En 438 12.8 En

440 12.7 Dr 450 12.0 En R Leo 094211 433 63 Ah 434 5 435 5.8Ah

437 5.5 Be 439 5.4Ah 440 5.7 Ah 441 6.2An 441 6.1Be 441 6.2Jo 443 5.5Ch 443 5.3 Tf 444 5.6 Ah 445 58 Pt 445 58Jo 446 5.4Pc 446 5.4Fd 447 5.8Jo 448 5.5 Ah 449 5.7 Me 450 6.0Sf 450 5.7 BL 450 5.6Wd 450 5.7Jo 450 5.5 Me 451 5.5Ma 451 56Al 451 54Bge 452 5.7 BL 452 5.6Wd 453 5.4Tf 453 5.7Jo 455 5.6BL 456 5.4Ah 456 5.6 Wd 457 5.4Tf

_ a - a ee i. oe i, oe

of Variable Star Observers

VARIABLE STAR OBSERVATIONS RECEIVED DuRING MAY

J.D.Est.Obs.

R Leo 094211 459 5.4Tf 459 5.5 Wd 459 5.3 Bg 461 5.7 Ma 461 5.6BL 461 5.7 Wd 462 5.7 BL 463 5.6 Ah 464 5.6 Ah 465 6.0SE£ 465 56BL 465 5.7 Wd 466 59Ma 496 5.5 Fd 406 5.8 Me 466 5.9Jo 467 5.8 Wd 468 58BL 468 6.1Vh 469 5.8 Oy 469 6.0 Jo 471 5.8 Wd 471 6.0Me 72 62Vh 473 6.2 Ah 474 6.2 Be 475 6.0 Pt 475 6.1 Oy 475 6.3 Fd 476 5.9 BL 476 6.4 Sf 477 6.0Oy 477 5.8 Wd 478 60BL 479 6.0 Be 479 60Sz 480 6.0 Be 480 6.2 Wd 482 6.6 Fd 484 6.2 Be 484 6.2Jo 186 6.0 Be 487 6.40Oy 487 6.1 Be 488 6.4Jo 488 6.5 Wd 490 6.5 Wd 490 63 BL 490 64B 494 6.2 Al 495 6.4Jo 495 6.5 BL 495 6.7 Wd 495 6.7Sf 499 65 Bg 502 6.6BL 506 6.8Sf

J.D.Est.Obs.

1 Car 094262 440 41 Dr Y Hya 0904622 413 8.2En 422 81En 438 7.0En 473 6.5 Pt 480 6.6Pt Z VEI 094953 410 12.2 En 411 12.6 Ht 411 12.3 Bl 415 12.8 Ht 417 12.6 En 421 12.9Ht 422 12.6 En 440 13.1 Dr 448 128 Dr 448 13.2 Dw 451 13.2 Bl 453 13.1 SI V Leo 095421 440 13.6 Ke 444 13.7 Ke 448 13.7 GC 450 13.7 Ke 451 13.4GC 452 13.5GC 453 13.7GC 467 13.6B 477 13.3B RR Car 005458 410 7.7 En 411 7.9Ht 415 79Ht 417 7.7 En 421 7.9Ht 423 74En 438 7.6En $2 79En 453 7.6 Ht RV Car

005563

411[13.1 BI

. 6 En 443 11.4Dr 451 11.2 Bl 452 11.4En 453 11.7 Ht 454 11.4Dr

J.D.Est.Obs.

S Car 100661 410 58En 411 5.5 Ht 411 5.5 Bl 415 <=

417 5.8E: 421 3s Ht 422 58 “ys 439 6.1 Er 440 37 Dr 440 5.9 SI 450 6.1SI 451 65Bl 452 66En 453 66Ht 454 67Dr 456 6.6S1 467 7.9Dr U UMa 100860 445 7.1Ch Z CAR 101058a

410 12.6 En 411 12.4 Ht 411 12.4Bl 415 12.6 Ht 417[12.6 En 423[12.6 En 441 13.5 Dr 448 14.1 Dr

448 13.6 Dw

452[12.6 En 453[12.6 Ht

454 14.2 Dw

454 14.0Dr * CAR

TOTO58b 441[13.6 Dr 448 13.6 Dr

448 13.7 Dw 454 14.1 Dw

454 13.8 Dr

W VEL

TOTT5? 12.0 En 12.0 Ht 11.7 Bl

411 411 411 415 417 421 423 11.8 En 439 441 93 451 S9OPRI 452 8.7En 453 88 Ht 454 86Dr

J.D.Est.Obs.

U Hya

103212 445 5.6Ch 469 6.1Mc 473 6.2Mc 474 63™Me 476 5.7 Mc 482 5.1Be

RZ Car

103270 411[13.6 Ht 415/13.6 Ht

03769 449 120Be 450 12.7 Pc 456[12.6 Wd 465 13.0 Wd 471 12.0 Jo 473 12.6 Pt 475 12.4B 480 12.4 Pt 494 11.9 Al 495 OWd 496 oo 498 V Hy. \ 104620

12. 11. 1]

ns

411

te Le) ax) PNINININNN

be 2) 2) r 2)

INIA NININNNININI9O 9

6.6 Pt RS Hya 104628

411 10.8 En

J.D.Est.Obs.

RS Hya 104628 411 10.5 Bl 416 10.8 En 423 11.1 En 439 11.7 En 451 11.9 Bl 452 12.0 En W Leo 104814 467[13.8B 477{13.8B RS Car TIO261 456[12.3 SI S Leo 110506 438 13.6 Ke 443 13.3 Ke 443 13.9L 448[13.5GC 450 13.5 Ke

490 11.6 Pt 483 11.9 Mp

RY CAR

AND JUNE,

413 1931. J.D.Est.Obs. X CEN 114441 411[13.1 Ht 415[13.1 Ht 417[13.1 En 421[13.1 Ht 439 13.1 En 441 13.5 Dr 452 13.5 Bl 452 12.9 En 454 13.3 Dr AD CEN 1174858 411 92En 411 9.1Ht 415 93 Ht 417 9.2En 421 94Ht 439 9.2En 441 85Dr 452 91En 453 94Ht 454 8.7 Dr *W CEN 115058

411 11.4En 411 11.7 Ht 411 11.0 Bl 415 11.0 Ht

417 10.6 En 421 99 Ht 423 9.7 En 427 93 En 439 91En 441 83Dr 451 8&3Bl 452 86En 453 8.3 Ht 454 80Dr R Cr M 115919 441 82]Jo 443 8.0To 446 79 To 450 82BL 451 &8Ch 451 7.7 Jo 451 83 Ws 452 85 BL 455 87BL 461 91BL 462 89 BL 465 90BL 465 88 Ws 467 9.0 Jo 471 94]Jo 473 98 Pt 476 94BL 478 9.46 BL 480 9.6 Pt

414

Monthly Report of the American Association

VARIABLE STAR OBSERVATIONS RECEIVED Dur1ING MAy AND JuNE, 1931. J.D.Est.Obs. R Hya

J.D.Est.Obs.

R Com 115919 490 9.7B 490 9.9 BL 495 10.2 BL 498 10.3 BL 502 10.5 BL SU Vir 120012 442 119L 445 12.1B 448 11.9 Mp 451 11.6 Ch 451 11.5 Ma 465 11.1 Bw 471 11.6L 473 11.5 Pt 474 11.5 Mp 475 114Me¢ 476 11.4Ma 480 11.4 Bw 480 11.4 Pt 483 11.5 Mp 489 11.3 Bw 496 12.0 Bw 510 12.2 Bw T Vir 120905 425 12.1L 440 13.0 Ke 445 128B 445 12.8L 449 13.5 Ke 472 13.1L 475[13.2 Mg R Crv 121418 17 L 12.9 SI 12.0L 13.2 S1 13.4 SI

426 440 443 447 456 467 472

122001 ee 8.8 Ke

J.D.Est.Obs.

SS Vir I2200I 471 8.0Jo 471 8.1Md 472 7.6L 480 7.3Bg 484 8.0Md 493 7.6Md T CVn 122532 438 10.0 Th 438 9.9 Ke 440 10.0 Th 444 98Ke 447 10.5 Pec 447 10.3 Fd 448 10.0 Th 449 9.7 Ke 451 10.0 Ch 452 10.0 Th 466 10.0 Th 472 98 Th 473 10.0 Pt 477 10.3 Fd 478 98Th 480 98 Pt 483 9.8 Th 484 9.6 Th 495 98Fd Y Vir 122803 426 11.7 L 445 13.1L 472 14.1L 475[13.6 Mg U Cen

TUN Ww

RrRhHKLS He

muiummyiwily lor

r

——

+ ie) So wwe SYevevvyvy>

J.D.Est.Obs.

T UMA 123160 9.8 Pc 9.5Jo 10.0 Fd 9.8 Jo 10.0 Wd 10.7 GC 10.2 Jo 11.0 Ah 10.4 Wd 10.9 Wd 10.7 Al 11.9 Pt 11.5 Fd 477 12.5 Bc 480 11.8 Pt 485[11.7 Fd 495 11.8 Wd R Vir 123307 8.0 Ah 8.1 Ah

446 447 449 450 450 452 456 456 459 465 468 473 477

434 435 439 440 84Ah 443 444 448 449 450 451 451 455 456 465

466

9.9 Me 10.0 Ah 10.2 Ws 10.1 Me 466 10.9 Ma 470 10.6 Me 473 10.8 Pt 480 11.0 Pt

338 8. 434 11.8 Ah 439 12.0 Ah 440 12.0 Ah 440 443 1 446 446 447 450

452 1

NNN GNNWdM

J.D.Est.Obs.

S UMA 123961 456 12.3 Jo 458 11.7 An 465 10.4Wd 468 10.2 Al 471 11.0Jo 473 10.4 Pt 477 10.3 Fd 477 98Bc 480 10.4 Pt 485 488 489 9 490 9. 490 10 495 9

504 9.2 Wd RU Vir 124204 99L 10.4 Ke Ee 10.0 B 10.4 GC 10.2 GC 10.3 Bw 9.9L 10.0 Pt 475 10.4 Mg 480 10.1 Pt 480 10.5 Bw 487 10.5L 495 10.6 Bw 510 10.7 Bw U Vir 124606 427 11.4L 442 12.0L 451 12.0 Ch 472 11.5L 473 11.8 Pt 480 11.9 Pt 482 11.3 Mg RV Vir 130212 426 13.8L 446 14.0L 451[14.1 GC 451[12.5 Ch 466[13.1 Bw i 480 12.7 Bw 495 12.2 Bw 510 12.1 Bw U Oct 131283 8.5 En

427 440 442 445 451 453 466 471 473

411

J.D.Est.Obs. U Oct

411 8.1Ht 411 415 421 80En 421 439 8. 441 84Dr 451 83 Bl 453 8.7 453 8.6Ht 454 8.6

\

1 449 7 462 7. 466 7 475 7

132002 440 9.4Ke 449 9.7 Ke 480 10.6 Bg 482 10.4Mg

V Vir 132202 444 11.2 Ah 447 10.6 Jo 449 10.2 Ke 450 10.4Jo 10.2 Ch 453 10.2 Jo 456 10.0 Ah 461 93Bg 468 469 471 9. 473 9 480 9 482 9

a

na A > leclecheab a 7

i)

DUD una gr Sra at ty be

4i1 411 414 415 418 420 421 425 427 428 438 439 440 445 445 447 451

SOmMYVNUN HAWN 7 nt

=

—

WSDOWOWROGOONMBWONKS Sit DOM DOH OHA

-_

peed ed ed ed et ed WY SA = =

es Se

Ninee ond Non -—- at HAA CeOR Ot al pl = 2 "pon —

\

HRAAHMR ACS aaonmy "Ra

a ms

O90 10 $0 90 10 1910 111! MH WOO OHA are

‘RocwHeNHEONNOhe

law | — lad

J.

46 4€ 4¢ 4¢ 4 4) 4) 4; 4) 4 4 4 4 4 4 4

ee i i

of Variable Star Observers

VARIABLE STAR OBSERVATIONS RECEIVED DuRING MAy AND JuNE, 1931.

J.D.Est.Obs. T UM1 133273

461 9.3 BL

462 94BL

465 9.5 BL

466 9.6 Th

471 98L

472 9.6Th

475 9.7 Th

476 98BL

478 10.0 Th

478 10.0BL

483 10.4 Th

484 10.4 Th

487 10.4L

490 10.5 BL

495 10.7 BL

498 10.9 BL

502 11.2 BL T CEN 133633

411 65En

411 6.2Ht

411 6.3 Bl

415 65Ht

421 65Ht

423 6.4En

427 63 En

428 6.7 Ht

439 7.0En

440 68S]I1

443. 7.2 Dr

447 73S]

449 8.0Me

451 82Me

451 78Bl

453 7.8En

453 84Ht

454 8.0Dr

456 7.9SI1

466 8.1 Me RT Cen 134236

411 11.0 En 411 10.9 Ht 411 11.0 BI 415 10.9 Ht 420 11.0 En 421 10.7 Ht 428 10.9 Ht 443 9.9 Dr 451 9.7 Bl 453 10.0 En

453 9.6 Ht 454 95Dr R CVn 134440 433 7.8 Ah 434 7.9 Ah 435 7.9 Ah

J.D.Est.Obs. R CVn 134440

439 8.1 Ah

440 8.0Ah

440 7.8Jo

444 8.0Jo

444 8.1 Ah

446 8.1Ch

447 7.7Jo

448 83 Ah

449 8.0Fd

450 7.9Jo

450 7.9 BL

451 82Ws

452 79 BL

455 8.2BL

456 84Ah

461 85 BL

462 87 BL

464 87 Ah

465 87BL

465 84Ws

473 88Pt

475 8.9 Ah

476 9.2BL

477 88Fd

478 94BL

479 9.0 Gy

480 9.0Pt

482 92Me¢

483 93B

490 96 BL

495 98BL

498 99BL

502 9.7 BL

905 10.2 Gy

RX CEn 134536

411 12.4En

411 12.9 Ht

411 12.8 BI

415 13.1 Ht

420 13.1 En

421 13.2 Ht

428[13.1 Ht

443 13.4Dr

453[13.1 Ht

454 13.6 Dr T Arps 134677

411 13.4 Ht

411 12.9BI

415 13.2 Ht

421 13.0 Ht

423 13.0 En

443 10.5 Dr

451 10.1 BI

453 9.2 En

453 98Ht

454 9.7 Dr

J.D.Est.Obs.

RR Vir 135908 451 12.5 Me 473 13.8 Pt 473 13.8B 475[12.5 Fd 482[14.1 Mg 483[12.8 Mp Z Boo 140113 425 11.5L 442 10.3 L 444 10.2 Ch 451 10.0 Ma 457 10.1B 471 9.9L 487 10.3 L 487 10.6B Z Vir 140512 426 14.3L 444[15.2 Ch 446[13.8L RU Hya 140528 411[13.5 Ht 421[13.5 Ht 428[13.5 Ht 450 14.0 Dr

450 14.1 Dw

452[13.5 BI

R Cen I40959 407 5.9En 411 59En 411 6.1 Ht 411 6.1BI 414 59En 415 6.1Ht 420 6.0 En 421 5.9Ht 423 6.0En 440 60Dr 440 58S] 443 61Dr 452 62Bl 453 58En 453 6.2Ht 454 63Dr 456 5.9S] U UMr 141567 434 9.3 Ah 439 92Ah 440 88Jo 440 9.1 Ah 444 92Ah 447 86Jo 447 90Pc 448 8.9 Ah

J.D.Est.Obs.

U UMr1 141567 450 85Jo 453 8.5Jo 456 88Ah 467 78Jo 471 8.0Jo 473 8.1 Pt 473 8.4Ah 475 83 Ah 480 8.0 Pt 483 7.8B 489 80Sz 499 83 Bg S Boo 141954

426 13.2L

442 13.4L

444 13.3 Ch 458 12.9 An 466[10.6 Th 470 11.9B

471 12.0 Pt 471 12.3 L

478 10.8 Th 480 11.7 Pt 483 10.6 Th 484 10.7 Th 484 484 487 498

142539a 434 O8Ah 439 95 Ah 440 95Ah 440 9.3]Jo 444 92 444 93 446 88 446 93 447 448 449 450 450 450

45 45 45: 45: 456

Renew oe) -i _"

J.D.Est.Obs.

V Boo

142539a 457 84Ah 457 87B 458 84An 460 85 Me 464 8.2 Ah 466 8.2 Me 466 9.0Fd 466 84Jo 467 8.2Vh 458 8.2 Vh 469 8.0Jo 469 86Mc 471 8.0 Pt 472 8.0 Vh 473 8.5 Mc 473 8.0 Ah 47 4 8 2 Mec 475 8.1 Ah 475 85Fd 476 8.0 Mc 476 8.2S8f 477 8.0B 480 8.1 Pt 488 7.7 Jo 495 7.9Sf 496 7.6Jo

R Cam

142584 439 93 Ke 443 8.9 Ke 449 8&7Ke 449 92GD 452 89Ch 183 8.0B 484 8.3 B; 485 83 Th 187 83 Th

R Boo

143227 433 7.9 Ah 434 78Al 435 9 Ah 439 7.9 Ah 440 7.9 Ah 440 78Jo 444 8 0Jo 444 80Ah 446 80Ch 446 7.8]Jo 448 81Ah 450 7.8To 450 8.1 Me 453 8.0Jo 455 8.2 Me 456 84Ah 45

J.D.Est.Obs.

R Boo 143227 8.4 Wd 8.7 Ah 8.5 Wd 8.7 Me 8.8 Jo 8.6 Wd 9.5 Wr 8.8 Jo 9.1 Pt 9.4 Ah 9.5 Ah 9.6 B 9.5 Pt 10.1 Mg 10.2 Sz 10.2 Wd V Lis 143417 115 LL 10.4 L 10.4 Me

461 464 465 466 466 467 470 471 471 473 475 5 477 480 485 489 489

426 442 449 467 470 471 479 1 480 1 B.

144646a 413 10.2 En 423 10.4 En 451 12.3 Sl 453 11.8 En U Boo 144918 12.2 Ke 12.0 Ke

439 444 444 449 12 461 465 4 18)

475

443 14.2 Dr 450 14.1 Dw

416

Monthly Report of the American Association

VARIABLE STAR OBSERVATIONS RECEIVED DuRING MAy AND JUNE, 1931. J.D.Est.Obs. J.D.Est.Obs.

V Aps 145471 443 9.5 Dr S Aps 145071 1 10.1 En 411 10.0Ht 411 10.0 Bl 414 10.1 En 415 10.1 Ht 421 10.0 Ht 423 10.1 En 440 9.9 Dr 443 98Dr 443 10.2 SI 452 10.1 BI 453 10.0 Ht 453 10.1 En 454 98Dr 456 10.1 SI 456 10.1 En RT Lin 150018 449 11.9 Me 455 12.2 Me 466 12.5 Me 471 13.1 Pt 480 13.5 Pt 485 13.5 Mg T Lis 150519 444 13.0Ch 487 13.1B Y Lin 150605 4% 11.3 L 442 12.2L 449 129 Me 450 12.8 Ke 465[11.3 Ws 471 13.2L 478 13.2B

NWN wa on)

NWwWARRRUWCAANNY

i ZOrHS =

en >

461 467

pa’ oO

[0 90 90 90 90 90 90 90 90 0 10 Ce

eg eer

487

S SER

151714

426 13.3 L

446 13.3 L 446 13.6 Pc 450 13.4Ke 466[12.6 Md

470 13.3B 471 13.4L ?

:s NI ore) _ we

485 487

Ig

Jonna o>

YY

> be un ee a a en ee

“DNDN DNDN Aww adlt load inal Vad Yet: XQ we

Sp RAUIWIY, se]

415 10.6 Ht 421 10.0 Ht 428 99 Ht 429 O8L 446 S88&L 449 84Me 453 86Ht 453 83En 467 8.0Me 471 7.9L 479 8.0RB 484 8.1Be 487 7.9L RU Lir 152714 429 10.8 L 444 11.8Ch 446 1 475 1; 478 1

414 415 418 421 424 428 443 453 453 455 9.8Dr

153215 444[13.0 Ch

J.D.Est.Obs.

S UM1

441 444 444 447 447 450 450 452 456 465 466 467 471 473 476 480 485 495 498

506

R

154428

423 425 426 429 434 435 439 440 440 440 442 442 443 443 444 444 444 444 445 445 446 446 446

153378

10.4 Jo 10.0 Jo 10.4 Ch 10.0 Sf 9.9 Jo 9.7 Jo 9.4 Me 9.8 Sf 9.5 Jo 9.5 Sf 8.9 Me 9.5 Jo 9.3 Jo 8.8 Pt 9.4 Sf 8.6 Pt 88 B 9.3 Sf 8.7 Gy 9.3 Sf

8.8 Dr 10.0 Ht 9.7 En 9.8 Dr CrB

6.0L 6.0L 6.0L 6.0L 6.1 Ah 6.1 Ah 6.2 Ah 6.3 Ah 6.5 Ke 6.0 Jo 6.0 Be 6.0L 6.0 Jo 6.0L 6.1 Ch 6.3 Ke 6.0 Jo

J.D.Est.Obs.

R CrB

446 447 447 447 448 448 448 448 449 449 449 449 450 450 450 450 450 450 450 450

154428 6.0 Gy 6.1 Ch 6.1 Pe 6.2 Pt 6.0 Jo 6.4 Gh 6.0 Ah 6.0L 6.0GD 6.2 Ke 6.0 Me 6.1 Pt 6.0 Be 6.1 Wd 6.0 Ke 6.0 Jo 6.2 Pc 6.0 Me 6.0L 6.1 Pt 6.2 Pt 6.0 Me 6.1 Wd 6.0 Jo 5.8 Tf 6.0 Jo 50k 6.0 Me 6.1 Ch 6.1 Wd 6.1 Ah By at 6.0 An 6.0 Be 6.1 Pt 6.2 Pt 6.1 Wd 6.0 Me 6.0 Wd 6.0L 6.2 GD 6.1 Pt 6.2 Pc 6.1 Wd 6.0 Be 6.2 Pc 6.0 Pt 6.0 Jo 6.1 Wd 6.2 Pc 6.1 Pt 6.0L 6.0 Mg 6.0 Mg 6.0 Mc 5.7 Oy 6.0 Jo 6.1 Mg

J.D.Est.Obs,.

R CrB

471 471 471 471 472 472 473 473 473 473

154428

6.0 Mg 6.1 Wd 5.8 Gy

6.0 Sz 6.1 Pt 6.1 Pt 6.1 Pt 6.0 Mg 6.1 Fd 6.0 Be 6.0 Mg 6.0 Jo

6.0 Mg

J.D.Est.Obs.

R CrB 154428 501 6.1 Pt 503 6.1 Pt 504 6.2Wd 504 6.0 Gy X CrB 154536 429 13.0 L 446 13.2L 473 13.5B 475 13.2 L R Ser 154615 438 10.4 Ch 446 10.8 Fd 446 11.0 Pc 452 11.1 Ch 461 11.4 Wd 465 11.3 Wd 11.0 Md

10.9 BL 10.5 BL 10.9 Md 11.3 Bw 10.5 B 10.8 Md 9.9 Pt 10.5 BL 10.4B 9.9 Pt 10.3 Md 10.7 Mg 10.6 Th 10.3 BL 10.3 Md 10.2 Bw 10.2 Md 10.5 BL 10.5 BL R Lis 154715 444 11.7 Ch 479 13.7B R Lup 154736 443 10.4Dr 454 10.0S1 454 10.0 En 455 10.0 Dr

498 498 502

~ a i ee i oe oe

—— -——

of Variable Star Observers

VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy ANpD JUNE, 1931.

J.D.Est.Obs. RR Lis 155018

429 14.0L

~) ft

1552 426 12.1L 444 10.0 Ch 446 10.0L 466 10.3 Md 471 10.4Md 475 10.0 L 484 10.8 Md 485 10.4B 491 10.6 L 493 10.6 Md 497 11.3 Md

RZ Sco 155823

9.5 Ht 9.2 Ht 9.1 Ht 9.2 Ht 9.1 En 9.8 Pt 10.0 Pt Z Sco 160021 415[12.2 Ht 426 12.2L

415 421 428 453 454 473 480

499[14.1 Be U Serr 160210

449 11.6 Fd

469 11.6 Me

473 12.2 Pt

480 12.4 Pt

X Sco

160221a

13.5 L, 475 128L 487 12.3 L SX Her

160325

8.0L

445

423 445 445 447 449 450

J.D.Est.Obs.

SX Her 160325 459 8.1 Pt 461 8.1L 462 8.0 Pt 466 8.3 Pt 467 82Pt 471 82Prt 472 8.2Pt 473 8.1Pt 475 83 Pt 476 8.6L 479 8.2 Pt 480 82Pt 481 8.1 Pt 485 8.1Pt 487 8.0 Pt 487 8.2L 488 8.0Pt 489 8.0 Pt 490 8.0Pt 493 8.0 Pt 494 81Pt 498 8.0 Pt 501 8.0 Pt 503 8.0 Pt RU Her 160625 422 80L 433 8.1 Ah 435 8.1Ah 438 7.8Ch 439 8.1 Ah 440 81Ah 444. 80Ah 445 7.7L 448 8.0 Ah 452 80Wd 456 8.1 Ah 461 8.1L 466 86Fd 473 83 Pt 475 8&8Fd 475 86Ah 476 8.7L 480 8.5 Pt 485 88B 487 8&7L 490 9.2BL 493 93Me 495 83Wd 498 94BL 502 9.4BL R Sco 161122a

415[12.6 Ht 428[12.6 Ht 454[12.6 En 473 12.8 Pt

J.D.Est.Obs.

S Sco 161122b 415[12.6 Ht 428[12.6 Ht 454[12.6 En 480 12.5 Pt W CrB 161138 473 12.2 Pt 480 12.0 Pt 495 11.1 Md W Opu 161607 429 9.9L 446 9.7L 455 10.4Me 466 10.8 Fd 473 11.2 Pt 474 11.4 Vh 475 11.0L 480 11.3 Pt V Op 162112 9.1L 10.1 L 9.9 Pt 10.7 L 9.8 Pt U Her 162119 9.9 Ah 10.2 Ah 10.0 Jo 10.0 Jo 9.9 Ch 10.1 Jo 10.6 Fd 10.2 Jo 10.3 Jo 10.3 Fd 10.8 Jo 10.9 Jo 11.2 Jo 11.0 Pt 10.3 Fd 11.1 Gy Pt Fc

429 446 473 475

480

434 439 441 443 444 446 447 450 453 466 466 469 471 473 475 479 480 1 482 1 484 1 485 1 Fd 485 11.1B 496[12.0 Jo

SS Her

162807 422 9.3L 445 10.3 L 461

1 1 1

) Jo

me oINTty

1. 1: 1.

J.D.Est.Obs.

SS Her 162807 487 11.8L 487 119B 499 99Bg T Oru 162815 O21, 9.3L 10.4 Pt 9.9L 10.3 Pt 11.4 Bw 11.4 Bw S Opn 162816 429 13.4L

429 446 473 475 480 507 510

441 444 446 450 450 456 456 469 471 474 476 489

9.3 Jo 9.3 Jo 9.2 Jo 9.2 Jo 10.0 Mc 90 To 9.3 Jo 90To 8.9 To 10.0 Me 10.0 Me 8.9 Jo R Dra 163266 441 11.8]Jo 443 12.0 Jo 444 12.0 Ch 449 12.1 Fd 450 12.0 Wd 465 4 466 471 475 480 480 482 488 489 495 495 498

—

oO

-

a oO m a + * &

a” op

pe beh feed fe ehh eyerqeryearsard <r" NMNWUNAONS

et ed ct et ed ey dq FY TJ 9 |

10.8 Wd 10.8 Wd 11.0 Jo

10.8 Gy

RR Oru 164319 426 13.8L

J.D.Est.Obs.

RR Opu 164319 446 13.8 L 473 11.5 Pt 475 11.3L 480 11.2 Pt 487 10.1 L

S Her 164715 435 9.2 Ah 439 9.2 Ah 440 9.3 Ah 441 8.8 Jo 444 88Ch 444 9.2 Ah 446 88Jo 450 8.0 Jo 456 8.5 Ah 464 83 Ah 467 84Jo 469 8.3 Jo 471 8.0Jo 473 7.8Ah 473 8.0 Pt 475 78Ah 480 7.5 Pt 484 7.5Jo 487 7.1B RS Sco 164844 415 10.5 Ht 421 10.4Ht 428 98 Ht 443 6.7 Dr 453 6.3 Ht 454 7.0 En 455 61Dr RR s¢ 0 165030a 415 63 Ht 421 59Ht 428 57Ht 443 5.6 Dr 453 5.9Ht 454 6.2En 455 5.5S]l 455 5.7 Dr SS Opn 105202 469 11.5 Md 473 98 Pt 480 9.5 Pt 495 9.0 Md RV Her 165631 423 12.3 L 440 9.5 Jo 444 96Jo 444 97Ch 445 10.6L

J.D.Est.Obs.

RV Her

446 446 448 452 461 466 466 469 469 473 476 480 480 482 484 487 487 490 493 495 496

RT

454

505

RT

444 493

165631 99 Pc 99 Fd 9.7 Jo 98 Jo 10.3 L 9.9 Jo 98 Bw 10.6 Md 98 Jo 9.9 Pt 10.3 L 9.6 Pt 9.9 Bw 10.3 Fd 10.1 Mg 10.2 B 10.1 L 10.4 Jo 10.2 Mg 11.4 Md 11.4 Jo

Sco

165636 12.4 En

R Opn

170215 7.0L 7.6 Jo 8.0 Ch 8.0 L 8.0 Jo 8.3 Fd

9.8 Jo 10.9 Gy Her 170627

[12.9 Ch [12.8 Mg

a Her

474 476

171014 3.0 Me 2.9 Mc

Z Oru

473 477

480

171401 11.9 Pt 12.0 Fd 11.9 Pt

418

Monthly Report of the American Association

VARIABLE STAR OBSERVATIONS RECEIVED DurING May AND JUNE, 1931. J.D.Est.Obs. T Her

J.D.Est.Obs.

RS Her

171723 441 10.3 Jo 446 10.0 Jo 450 453 456 466 466 469 473 475 480 480 493 495 496

Ca

h

Duy 2c

NIN 90 90 90 90 90 90 90 G0 $9 10} s i)

by & iv in & BOO

yn

173643 443 11.1 Dr 455 11.0 Dr

W Pav

174162 415[13.0 Ht 428[13.0 Ht 443[13.4 Dr

J.D.Est.Obs.

W Pav 174162 455[13.6 Dr RS Opn 174406 473 11.1 Pt 480 11.1 Pt U ARA 174551 415 13.0 Ht 428[13.0 Ht 443[13.4 Dr 455[13.5 Dr RT Opu 175111 446 9.7 Fd 446 98Pc 473 10.5 Pt 480 10.6 Bw 480 10.7 Pt 489 10.8 Bw 496 10.8 Bw 510 11.4 Bw RY Her 175519 423 10.4L

421 10.3 3 Ht 428 10.6 Ht 443 11.4 Dr

461 466 466 467 469 471 471 473 473 475 475 475 476 477 479 479 482 487 496 501 505

180531 11.4L 10.7 Fd

9.5 Me 97 Jo 9.6 Jo 9.4 Me 9.4Jo 9.3 Pt 9.3 Ah 8.8 Fd 9.2 Ah 9.1Vh 8.8L

9.4GD

8.7 Gy 9.3 Be 8.9 Fd 8.3 L

a2 Jo i2 Ft 8.0 Gy

W Dra

423 447 476

423 446 476

180565

180666 11.0L 11.7L 3.3 1. V Her 181031 We he 12.9L 13.41.

RY Orn

474

181103

8.0 Dr 8.3 Me

J.D.Est.Obs.

SV Her 182224 425 14.2L 446 14.0L 473 13.0 Pt 476 13.2L 489 12. 7 Bw 495 12.5 Bw 501 11.9 Pt T Ser 182306 473 12 4 Pt 489 11.5 Bw 496 11.5 Bw 501 11.0 Pt SV Dra 183149 423 14.1L 448 14.4L 477 14.5L RZ Her 183225 423 9.5L 446 9.9L 476 11.9L X Opn 183308 25 273i. 444 445 447 447 449 450 456 467 471 473 476 484 487 497 68 Aw 501 6.9 Pt 503 6.6Aw RY Lyr 184134 423 11.0L 446 10.4L 473 11.8 Pt 476 11.8L 501 12.2 Pt

tt lt o>) mae -@

WOMUADADOONWWOR roo

ye

\

ANNAN NAAANNNNNN

TO

> = =

R Scr

184205 423 6.4L 445 5.5L 447 5.5 Fd 449 5.6Fd 449 5.6Me 450 5.4Pe 450 5.6Jo

J.D.Est.Obs.

x. Scr

184205 450 5.6Pt 451 451 454 455 455 456 460 465 466 471 471 472 474 474 475 475

476

wn

os 2m ioe’ »

oh de ike) or SO gar

DtnpwUMnQNndDApRWUBRN OH waes

477 477 477 479 479 480 481 485 485 486 487 488 488 489 493 495 501 5. 503 5.9 Pt 504 5.8 Wd Nov AOL 184300 450 11.7 Pt 471 11.7 Pt

AMUMUnuUniwnini nnn wiwnonim wn ure

a vrvvs ag a

C0 to tn DO DOW NAMAWwWROOM °

gud

MANNION On ON UT Tt —oP ee OQ ot et

© 00 ya

TUN _

479 11.8 Pt 497 11.7 Pt 501 Lis Pt RX Lyr 185032 473 13.0 Pt 501 13.5 Pt R Lyr

468

J.D.Est.Obs.

S CrA 1854374 428 11.9 Ht 451 11.5S1 453 11.7 Ht 455 12.7 Sl ST Scr 185512a 477[12.5 Fd R CrA 1855374 428[12.5 Ht 451 11.7 Sl 453 12.5 Ht 455 11.9 SI T CrA 185537b 428[12.5 Ht 451 13.0S1 455 13.0SI1 Z Lyr 185634 423 13.8 L 446 13.8L 473 11.4 Pt 476 11.7 L 491 10.2L 501 10.0 Pt SU Scr 185722 428 8.6Ht 453 8.4 Ht

456 10.5 Ah 473 11.1 Pt 475 11.1 Ah 501 11.4 Pt V Lyre 190529a 450 14.0 Fd RX Sar 190818 428 10.5 Ht 445 10.0L 447 10.2 Pt 453 9.9 Ht 460 9.6Ch 475 10.1 L 501 11.0 Pt

cn +

em a SO De

VARIABLE STAR OBSERVATIONS ‘RECEIVED DurING MAy

J.D.Est.Obs. RW Scr

1908 19a 423 9.6L 428 9.6 Ht 445 9.4L 447 98 Pt 453 9.6 Ht 460 9.6Ch 475 9.6L 501 9.0 Pt

TY AQ.

190907

447 10.3 Pt 501 10.2 Pt S Lyr 190925 479[12.3 Gy 505[12.9 Gy X Lyr 190926 473 9.0 Pt 501 8.8 Pt RS Lyr 190933a 425 10.9L 446 12.1L

489[13.4 Bw

505[12.7 Gy U Dra 190967 5 1394, 8 13.8 L

191007 446 11.4L 475 11.8L 501 12.2 Pt

T Sar

191017 447 10.8 Pt 460 11.3 Ch 501 11.8 Pt

R Ser

IQIOIQ 425 68L 428 7.1Ht 446 7.0L 447 5 Pt 449 5 Me 453 5 Ht

4. J

00 00 CO SININININININS mu

J.D.Est.Obs. RY Scr 191033

428[12.5 Ht

443 12.5 Dr

451 12.3 Sl

453 12.5 Ht

454 12.7 Dr

455 11.981

475 11.8L

481[12.0 Pt

487 11.6L

489[12.0 Pt

501[12.0 Pt

507[11.5 Pt TY Scr

455 11.7 Dr S Scr 191319a

425 10.2L

428 10.8 Ht

446 11.1L

447 P

449

453

455

477

TON eed!

SD tm tne Go Go

+ NX aN —

N i oN F »L

SW “Scr 191331 13.1 Dr

446 10.6 Fd 446 10.7 Pe 473 10.0 Pt 501 10.5 Pt U Lyr

191637

10.9 Jo 10.7 Jo 447 10.8 Fd 450 10.6 Jo > 10.6 Jo 10.7 Fd 7 10.9Jo 10.8 Jo 10.0 Pt 10.6 Fd 2 10.8 Fd 10.7 Jo

44] 446

t Te It fe d

J.D.Est.Obs.

AF Cyc 192745 444 68Ah 448 69 Ah 456 6.5 Ah 463 6.4Ah 464 65Ah 473 6.6 Ah 475 66Ah LY Cye 192928 429 10.2 L 446 9.9L

477 10.3 L 491 10.5L 501 10.8 Pt RT Aor 193311 426 14.21

193449 447 13.5 Pt 501 14.0 Pt

RV Aor

193509 426 11.1L 447 93Pt 448 9.9L 477 10.1L 491 10.9L 501 11.5 Pt T Pav 193972

12.0 Ht 12.0 Ht 11.3 He 10.2 S1 10.1 Dr 8.6 Ht

415 421 428 443 443 453 455

x "Cya

_ ek ek et et et OOS

WSOP HNKENNE

44]

446 447 450 456

+t N 4. —

BSN “SJ un

by mio Nitin dd NO ONNYE 1

BSS

22

o SINT OO C0 90

coYTIC

J.D.Est.Obs. TU Cyc 194348 14.1 L 13.1 Pt 448 144L 476 12.8L 501 10.9 Pt X AOL 194604 429 148 L 448[14.4L 477[14.4L x Cyc 194632 447 13.5 Pt 451[13.4 Ma 479 12: 9 Bg 479 482 484 495 499 501 10. 2 Pt S Pav 194659 8.1 Dr 7.6 Dr RR Scr 1949020 7.2 Dr

426 447

443

447 12.3 Pt 448 120L 477 13.4L RS AOL 195308

3.8L

J.D.Est.Obs.

Zz Cye 195849 448 13.2L 476 14.5 L 501 12.4 Pt S Tet 195855 428[12.6 Ht 453 12.8 Ht SY Ao. 200212 425 12.8L 448 13.0L 477{14.3 L S Cyc 200357 447 12.6 Pt 479[12.3 Gy R Cap 200514 Rue hs S AOL 200715a 447 9.6 Pt 449 9.5 Fd 449 9.6 Me 455 472 1 477 11.5 501 11.6 Pt RW Aor 200715b 447 93 Pt 501 9.2 Pt R Tex

477

AND JUNE,

9.8 Me 1.2 Me Me

1931.

J.D.Est.Obs.

mS (ve 200938

+

Re po 90 ONL I

8 OW d 8.4 Jo 7.6 Pt 8.8 GD R Der 201008 10.5L 11.1 Pt 119 kL

501 501

425 447 448

447 68Pt 449 7.9Fd 477 8.2Fd SX Cyc 201130 447 10.0 Pt 501 12.2 Pt RT Scr 201139 443 9.7 Dr 455 89 Dr WX Cyc 201437b 425 11.51 441 10.7 Jo 445 10.8L 446 10.5 Jo 447 10.5 Pt 450 10.4 Jo 456 10.7 Jo 461 10.7 L 467 10.4 Jo 471 10.5 Jo 477 10.7 L 491 9.7L 496 10.6 Jo 501 9.1 Pt

201 441 8 446 Pa] 447 8 449 8 450 88 Jo 455 456

9.0 Jo

420

Monthly Report of the American Association

VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND Jung, 1931.

J.D.Est.Obs.

U Cre

201647 469 87Jo 471 88Jo 474 477 1 478 479 482 487 487 10. 489 495 496 501 504

wovyeyyrss DOD DWDM wW~ AQ2nts2nN2z

bed Lm —

~ Ts) Qo. ata

202240 443 81Dr 455 8.3Dr RW Cyc 202539 455 83Me Z DEL 202817 426 12.9L 448 11.5L 477 9.3L 491 88L 501 9.2 Pt ST Cye 202954 429 11.0L 447 10.6 Pt 448 10.9L 449 11.2 Fd 471 11.0 Jo 477 10.4L 479 10.6 Gy 498 10.5 Gy 501 10.8 Pt V VuL 203226 447 89 Pt 501 86 Pt Y Dex 203611 429 14.0L 477 13.8L S Det 203816 447 92Pt 501 88Pt

J.D.Est.Obs.

V Cye 203847 477 13.3 L 501 13.6 Pt Y Aor 203905 449[12.0 Fd 485[12.3 Fd T Det 204016 425 11.4L 447 12.5 Pt 448 12.4L 477 12.9L 503 14.5 Pt V Aor 204102 429 85L 447 8.0L 454 86L 486 8.6L W Aor 204104 426 10.5L 454 10.2L 486 9.6L U Cap 204215 486/13.5 L T Aor 204405 447 92Pt 449 90Fd 485[12.3 Fd RZ Cyc 204846 447 12.1 Pt 449[12.4 Fd 485 11.6 Fd 503 11.3 Pt S Inp 204954 428[13.1 Ht 443[13.8 Dr 455[14.0 Dr X DEL 205017 425 12.4L 448 12.8L 486 14.2L RR Cap 205627 455 13.8 Dr T Oct 205782 441 13.1 SI 443 13.0 Dr 451 13.4 Sl

J.D.Est.Obs.

R Vut 205923a 447 9.5 Pt 450 9.0Jo 456 88Jo 456 8.9 Ah 474 9.1 Me 475 9.0 Ah 496 10.5 Jo 503 11.5 Pt V Cap 210124 505[12.5 Gy TW Cyc 210129 429 12.0L 448 12.6L 486 12.1 L RS Aor 210504 454 12.3 L 486 11.4L 503 11.0 Pt R Eou 210812 429 13.9L 448 11.9L 503 10.5 Pt T Cep 210868 433 8.6A h 434 87Ah 35 87 Ah 439 87Ah 440 88Ah 440 82Jo 443 8.5 Jo 444 89 Ah 446 8.7 Jo 446 9.2 ( IV 447 86Pt 447 90Fd 448 9.1Ah 449 93Fd 450 8.9 Jo 451 9.5 Gy 453 9.1 Jo 456 9.3 Ah 466 9.4Fd 466 9.2Jo 471 93]Jo 475 9.9 Ah 475 9.4Fd 477 9.7 Fd 479 98 Gy 481 9.6 Pt 482 9.5 Fd 485 9.5 Fd 486 12.8L 490 9.6Jo

J.D.Est.Obs,.

T Cep 210868 496 98Jo 498 10.0 Gy RR Aor 210903 425 9.5L 445 10.5L 447 10.6 Pt 477 129L 481 12.6 Pt Y Pav 211570 428 5.5Ht 453 58Ht X PEc 211614 426 11.5L

21 3678 447 11.7 Pt 449 12.2 Fd 481 11.8 Pt 485 11.8 Fd

RU Cyc

213753 434 439 7. 440 7.9 Ah 444 447 7 456 7 474 8 474 7 475 7

447 6.7 Pt

J.D.Est.Obs.

RR Pec 214024 449[12.6 Fd 487 13.0 Pt R Gru 214247 455 11.9Dr V Pec 215605 426 10.5L 449 11.7 Fd 454 12.2L 486 13.6L U Aor 215717 486[12.2 L RZ Perc 220133b 426 9.3L 448 9.2L 450 9.1 Pt 461 9.1L 486 9.4L 487 9.5 Pt T Pre 220412 426 9.7L 454 9.5L 486 9.7L 505 11.0 Gy RS Perc 220714 454 13.5L 486 13.3L S Gru

486 128L

J.D.Est.Obs.

R Lac 223841 429 14.0L 454 13.4L 486 9.7L RW Perc 225914 454 12.3L 485 10.2 Fd 486 10.5 L 487 10.0 Pt R Pec 230110 479 11.6 Gy 487 12.0 Pt 505 11.5 Gy V Cas 230759 456 85 Ah 447 85 Pt 475 78Ah 488 7.2Pt W Pec 231425 429 10.7 L 454 10.5L 477 9.1Fd 486 8.9L S Perc 231508 454 9.0L 486 10.5 L 488 10.5 Pt V PHE 232746 455 99Dr Z AND 232848 395 10.0Rs 450 10.2 Pt 474 10.4 Me 488 10.4 Pt ST ANpb 233335 447 9.0Pt 477 9.2 Fd 485 8.9 Fd 488 8.9Pt Z Cas 233956 377[12.1 Gh 424 13.7 L 454 11.3L 485 11.0 Fd 486 11.2L R PHe 235150 455[12.9 Dr

of Variable Star Observers

VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND JuNE, 1931. J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs. R Tuc R Cas R Cas R Cas R Cas Y Cas 235205 235350 235350 235350 235350 235855 411[13.3Ht 419 62Wd 425 67Jo 436 7.2Jo 479 85Gy 425 116L 421[13.0Ht 419 66Jo 427 63Ah 439 66Ah 495 80Gy 454 11.5L 455{13.5Dr 420 63Ah 428 64Ah 440 66Ah Z PEG 486 11.6L R Cas 421 64Ah 431 65Ah 440 7.5Jo 235525 SV AND 235350 422 61Wd 433 65Ah 446 7.5Jo 454 82L 235939 62Ah 422 66Jo 434 65Ah 450 7.5Jo 486 9.3L 488 11.2 Pt 6.2Ah 424 64Ah 435 65Ah 456 7.2Ah 488 9.1 Pt RAPIDLY VARYING IRREGULAR VARIABLES. Star J.D. Est.Obs. J.D. Est.Obs. Star J.D. Est.Obs. J.D. Est.Obs. 005840 RX ANpDROMEDAE— 074922 U GeMINoRUM 6450.97 11.5 Pt 6488.9 13.1 Pt 6447.5 9.9 Gh 6452.6 13.3 GC 6487.9 12.3 Pt 6489.9 12.6 Pt 6447.5 10.0 Rs 6452.9 13.5 Sl 060547 SS AvurRIGAE— 6447.9 98SI 6453.6 13.5 Bg 6419.6[13.2 Gh 6455.6 11.2 Me 6448.5 10.1 Rs 6453.6 13.2B 6423.6 14.7 L 6458.1 11.3 Ch 6448.5 10.0 Gh 6453.9 13.6 Sl 6425.6[14.5 L 6459.6 11.1 Bg 6448.6 10.3 Ge 6454.4 13.6 L 6426.6[13.9 L 6459.8 11.3 Pt 6449.6 11.0B 6457.6[13.0 B 6429.4[12.5 L 6460.6 11.1 Bg 6449.7 10.9 Me 6459.6[13.3 Bg 6430.3[12.5 L 6460.7 11.3 Me 6449.7 11.0 Ke 6465.6[13.3 Bw 6431.3[13.3 L 6461.3 11.0 L 6449.9 11.0 S1 6467.4 13.6 L 6437.1[13.3 Ch 6461.6 11.3 Me 6450.3 11.4 L 6467.6[13.8 B 6442.4 14.7 L 6461.6 11.3 Bg 6450.6 12.0 Pe 6467.7[12.7 Me 6443.3[14.5 L 6462.6 11.8 B 6450.6 12.0 Be 6469.6 13.5 Mg 6444.6[12.5 Mp 6462.7[12.0 Pt 6450.6 12.3 Rs 6470.6 14.01 6445.6[13.9 B 6465.6 13.6 Bw 6450.7 11.6 Me 6473.6 [126 Me 6446.3[13.9 L 6466.7[12.6 Pt 6450.9 12.3 SI 6473.7[13.3 Mg 6447.3[13.9 L 6467.3 14.2 L 6451.1 12.5 Ch 6474.7[12.7 Me 6447.7[13.5 Pc 6469.6[13.2 Mg 6451.6 12.8 GC 6475.6[13.8 Mg 6448.5[12.6 Gh 6470.7112.7 Me 6451.6 12.8 Bg 6478.6 13.9B 6449.6[13.9 B 6473.6[13.9 Mg 6451.6 12.5 Rs 6479.6 13.7 Be 6449.8[12.6 Pt 6474.7[12.6 Me 6451.6 12.3 Gh 6480.6[13.3 Bg 6450.3 14.5 L 6475.6{13.2 Mg 6451.6 12.8 Mg 6480.6/13.3 Bw 6451.1 13.2 Ch 6478.7[12.5 Me 6451.7 12.7 Me 6489.6[12.4 Bw 6451.6 12.7 Rs 6479.6[13.9 Bg 6451.9 13.0 SI 6496.6[12.4 Bw 6451.6 12.7 Gh 6479.8[12.0 Pt 081473 Z CAMELOPARDALIS 6451.6 12.8 Mg 6480.7[12.0 Pt 6423.4 11.2 L 6455.6 11.8 Me 6451.7 12.5 Me 6481.7[12.6 Pt 6425.4 11.2L 6460.4 11.5 An 6452.6 11.9 Me 6482.6[13.2 Mg 6426.3 11.6 L 6460.4 11.6 Be 6453.6 116B 6494.7[11.0 Pt 6428.3 11.7 L 6461.3 11.4L 6453.6 11.8 Rs 6501.7[12.6 Pt 6429.4 11.7 L 6461.6 11.7 Bg 6454.4 10.9L 6430.3 11.7 L 6465.4 12.6 Md 074922 U GemInoruM— 6431.3 11.8 L 6465.6 12.6 Me 6423.4 13.7 L 6443.0 9.5 SI 6438.2 11.2 Ch 6466.7 12.7 Me 6425.4 13.7 L 6443.4 9.0L 6439.6 12.1 Ke 6467.4 12.3 L 6426.3 13.8 L 6444.0 9.6 SI 6442.4 11.4L 6467.7 12.8 Me 6428.3 13.8 L 6444.2 9.3Ch 6442.6 11.4L 6468.7 12.6 Me 6431.4[10.9 L 6444.6 9.5Gh 6445.3 11.7 L 6469.7 12.8 Me 6435.9 9.0S1 6445.3 9.0L 6446.3 11.8 L 6470.7 12.8 Me 6436.1 9.1 Ch 6445.6 9.2Gh 6447.3 11.7 L 6471.6 12.1 L 6436.9 9.0SI1 6445.9 9.7 Sl 6449.7 11.8 Me 6471.7 13.0 Me 6437.9 9.0S1 6446.3 9.1L 6450.3 11.8 L 6472.3 12.5 L 6438.7 9.6 Ke 6446.5 9.5 Gh 6450.7 12.1 Me 6472.7 12.8 Me 6440.0 9.0SI1 6446.5 9.5 Rs 6451.6 12.1 Bg 6472.9 12.6 Me 6440.9 9.3 Sl 6446.7 9.6 Fd 6451.7 12.3 Me 6473.6 13.0 Me 6441.9 94S] 6446.7 10.0 Pc 6452.6 12.2 Me 6474.7 11.4 Me 6442.4 9.3L 6447.3 9.3L 6454.4 11.6 L 6474.7 11.4Vh

422

Monthly Report of the American Association

Star J.D. Est.Obs.

VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND JUNE, 1931.

J.D. Est.Obs.

081473 Z ‘\CAMELOPARDALIS

Star

J.D. Est.Obs. 213843 SS Cyen1—

6474.8 11.3 Vh 6480.7 11.7 Me 6439.4 9.7 Ah 6474.8 11.4 Me 6481.7 11.7 Me 6440.5 9.6 Ah 6474.9 11.2 Me 6482.7 11.7 Me 6441.8 9.7 Jo 6475.6 10.8 L 6483.7 11.9 Me 6442.6 9.7L 6475.7 10.9 Me 6484.6 12.0 Bg 6444.5 10.2 Ah 6475.7 10.9 Me 6484.7 11.9 Me 6445.6 10.1 L 6475.7 10.8 Vh 6485.8 11.9 Me 6446.6 10.2 L 6476.4 10.7 L 6486.5 11.5L 6446.7 10.7 Fd 6476.7 10.9 Me 6486.7 12.1 Me 6446.8 10.3 Jo 6476.7 10.9 Me 6487.5 12.2L 6446.8 10.7 Pc 6476.7 10.9 Vh 6487.7 12.2 Me 6447.8 11.6 Pt 6477.6 10.9 L 6488.9 11.7 Me 6447.8 11.0 Fd 6477.8 11.2 Me 6489.9 12.0 Me 6448.6 11.3L 6478.7 11.5 Me 6490.7[11.9 Me 6449.8 11.8 Fd 6479.7 11.6 Me 6491.5 12.3 L 6449.8 11.7 Pt 6479.6 11.4 Bg 6497.7 12.6 Me 6449.9 11.8 Me 6480.6 11.2 Bg 6499.6 11.0 Bg 6450.8 12.0 Fd 094512 X Lreonis— aaa a ; r 6447.6 12.2B 6474.4 12.4 Be 6450.9 117 Pt 6451.6 13.3 B 6479.6 12.4 Bg woe cote aos id : <a 6451.8 11.9 Ma 6445.7[11.8 Pt 6480.6 12.5 Be 6454.6 11.61 6467.6[13.4 B 6499.6[12.6 Be 6455.0 118 Me 202946 SZ Cycni— 6456.5 11.5 Ah 6447.8 9.0 Pt 6481.7 9.6 Pt 6456.8 12.0 To 6449.8 9.5 Pt 6485.8 9.6 Pt 6460.4 11.7 Ch 6450.8 9.0 Pt 6487.9 9.2 Pt 6460.8 11.6 Ma 6466.7 9.6 Pt 6488.9 9.0 Pt 6461.6 11.1 L 6467.7 9.6 Pt 6489.9 8.8 Pt 6461.8 11.4 Ma 6471.8 9.6 Pt 6490.7 9.0 Pt 6465.8 10.2 Ma 6472.7 9.4Pt 6493.7. 9.0 Pt 6466.9 10.1 Ma 6473.7 9.0 Pt 6494.7 9.4 Pt 64678 9.2Ma 6475.7 9.0 Pt 6501.7 9.3 Pt 6470.8 10.2 Ma 6479.8 9.0 Pt 6503.8 9.3 Pt 64716 10.2L 6480.7 9.2 Pt 6471.7 10.7 Jo 213843 SS Cyreni— 6471.8 10.4 Pt 6423.7 11.4L 6426.7 11.5 L 6472.7 10.8 Pt 6425.7 11.4L 6429.6 11.4L 6472.9 10.4 Me SUMMARY OF OBSERVATIONS FOR MAy AND JUNE, Observa- Observer Initial Vars. tions Observer Initial Adwell Aw 1 : Godfrey Club GD Ahnert Ah 35 199 Gooch Gh Allen, P. R. Al 7 9 Gregory Gy Ancarani An 8 8 Houghton Ht Baldwin Bl 54 116 Jones Jo 3enini Be 9 18 Kline Ke Bigelow Bw 20 52 Lacchini # Boutell BL 16 95 Marsh Ma Bouton 3 69 105 McLeod Mc Buckstaff 3c 9 11 McPherson Mp 3unting Bg 27 66 Meek Me Chandra Ch 86 105 Mennellay Mn Dartayet Dr 82 150 Monnig Mg Dawson Dw 10 12 Millard Md Ensor En 67 240 O’Byrne Oy Ford Fd 62 124 Peltier Pt Georgetown GC 10 22 Proctor Pe

J.D. Est.Obs.

6473.4 10.7 Ah 6474.8 11.4 Me 6475.5 11.3 Ah 6475.6 11.4L 6475.7 11.6 Pt 6475.7 11.7 Fd 6476.8 11.6 Ma 6477.6 11.5L 6477.7 11.5GD 6477.8 11.7 Fd 6477.8 11.6 Me 6479.8 11.7 Pt 6480.7 11.7 Pt 6481.9 11.7 Pt 6482.7 11.6 Me 6485.8 10.6 Me 6485.8 10.3 Fd 6485.8 10.5 Pt 6486.6 10.2 L

6487.6 9.8L 6487.9 10.3 Pt 6488.1 9.8Bec 6488.9 10.0 Me 6488.9 10.0 Pt 6489.9 9.9 Pt 6493.7 11.5 Pt 6494.7 4 7 Pt 6495.6 11.3 Wd 6495.6 11.3 Bg 6499.6 11.1 Bg 6501.7 11.7 Pt 6503.8 11.7 Pt 6504.7 11.2 Wd 6510.7 8.5 Jo 6510.8 8.4Ma 6511.7 8.4Ma 6512.7 8.4Ma 1931. Observa- Vars. tions 8 16 5 13 29 48 77 261 63 349 26 58 159 566 8 24 16 42 7 13 54 168 6 8 31 56 9 23 3 181 425

34 44

Notes from Amateurs

Observa- Observa-

Observer __[nitial Vars. tions Observer Initial Vars. tions Ross Rs 4 9 Vorhies Vh 8 15 Shinkfield Sl 36 88 Wares Ws 7 11