ASTRONOMY, PROGRESS OF, IN 1890. 



37 



15|, 18J, and 36 inches respectively. A large 

 majority were detected with the 6-inch. His 

 catalogues include Beta Cancri, Beta and Mu 

 Draconis, and Alpha, Theta, and 78 Ursae Ma- 

 joris. With a power of 8,800 diameters on the 

 80-inch telescope no duplicity nor elongation, as 

 he had formerly suspected, was apparent in Beta 

 Orionis ; neither was any companion seen nearer 

 to the pole star than the well-known one, not- 

 withstanding the oft-reiterated published state- 

 ments that one or more had been seen with tele- 

 scopes of 3-inch aperture. He expresses the 

 opinion that, even at periastron, the companion 

 of Sirius will not get beyond the reach of the 

 36-inch telescope. 



Prof. G. W. H'ough, of the new Dearborn Ob- 

 servatory at Evanston, 111., has published in the 

 same periodical, Nos. 2,977 and 2,978, a second 

 catalogue of 94 new and difficult pairs, the dis- 

 tances of 48 of them ranging from 0*25" to 0'5". 



Nebulae. No notice of newly discovered nebu- 

 lae has been given in these annual reports since 

 1887, when the publication of the sixth list of 

 100 each discovered at Warner Observatory, 

 Rochester, N. Y., was chronicled. Since then, 

 its director has made public, in the " Astrono- 

 mische Nachrichten," his seventh, eighth, and 

 ninth catalogues of 100 each. The majority of 

 these bodies are of unimagined faintness and" be- 

 yond the ken of most telescopes, and of eyes not 

 trained for the work. Since the days of the 

 Herschels, the principal astronomers who have 

 kept up this quest so auspiciously begun by Sir 

 William, have been D'Arrest, Stephan, Rosse, 

 Stone, Marth, and Swift. Nearly 8,000 are now 

 catalogued, and it seems safe to predict that 

 10,000 will soon be known visually, while a 

 vastly greater number will be revealed pho- 

 tographically. Already the camera has shown 

 quite a number beyond the reach of the Lick or 

 the Rosse telescope. At Leander McCormick 

 Observatory, Virginia, Prof. Stone has discovered 

 several hundred, mostly south of the equator. 

 Prof. Barnard has found 150, and at the Lick 

 Observatory, with the 12-inch glass, he detected 

 five in a field the size of the moon. A few months 

 ago Mr. Burnham, of Lick Observatory, discov- 

 ered with the 36-inch telescope eighteen nebula? in 

 a space only about one eighth the apparent size 

 of the moon. They are very faint and exceed- 

 ingly small, and if seen at all with other tele- 

 scopes would be mistaken for small stars. The 

 approximate mean place of the group is right 

 ascension 18 h 38 m , declination north 56 20'. In 

 the search for these objects, a comet is occasion- 

 ally discovered, as was the case in November last 

 when a comet, which proved to be of short period, 

 was found by Dr. Swift, of Warner Observatory. 



Star Catalogues. Carleton College Observa- 

 tory, Northfield, Minn., has recently issued, as 

 Vol. I of its publications, a catalogue of 644 

 comparison stars observed with the Repsold 

 Meridian Circle by Prof. H. C. Wilson during 

 1887-'89. The Washburn Observatory, Madison, 

 Wis., has lately sent out its Vol. VI, Parts 

 I and II. Part II is devoted to observations of 

 double stars by Prof. George C. Comstock. It 

 gives the results of the remeasurements of all 

 double stars discovered there by Burnham and 

 others. The Greenwich Ten-Year Catalogue 

 of 4,059 stars for the epoch of 1880, deduced 



from observations made from 1877 to 1886, un- 

 der the direction of the Astronomer Royal, W. 

 H. M. Christie, has been issued. It is valuable 

 for the working astronomer. A list of 10,792 

 stars, including those down to the tenth magni- 

 tude, observed between 1857 and 1878, has been 

 recently published by the Brussels Observatory. 

 Vol. XI of the Argentine National Observa- 

 tory, being a separate annual catalogue, already 

 combined in the gigantic catalogue, Vol. XIV, 

 of Dr. B. A. Gould, has lately been issued. Two 

 more numbers, under the supervisorship of his 

 successor, Dr. J. M. Thome, which will complete 

 the series, are to be published. The second 

 Melbourne General Catalogue, of 1^211 stars, has 

 just appeared. They are mostly southern stars. 

 Baron von Engelhardt has recently sent out 

 from his private observatory at Dresden, Ger- 

 many, a book of 272 pages, devoted to observa- 

 tions of asteroids, comets, double stars, and the 

 nebula?. Two hundred and fifty pages are taken 

 up by a catalogue of 203 nebula?, which he has 

 micrometrically examined. It is the most con- 

 cisely arranged catalogue ever issued from any 

 observatory. 



Solar Parallax. Prof. William Harkness, 

 member of the Transit of Venus Commission, to 

 whom was assigned the task of determining the 

 solar parallax from the photographs taken with 

 the horizontal photo-heliograph of about 40-foot 

 focus during the transit of Venus in 1882, re- 

 ports to Captain R. L. Phythian, Superintendent 

 of the Naval Observatory, Washington, as fol- 

 lows : " From position angles measured on 1,426 

 photographs, parallax = 8'772" 0*0496. From 

 distances measured on 1,475, parallax = 8'847" 

 0-0122. Weighted mean, both from position- 

 angles and distances, parallax = 8-842" 0-0188. 

 With a parallax = 8'842" 0-0188, and with 

 3,963-296 miles for the equatorial radius of the 

 earth, the mean distance from the earth to the 

 sun is 92,455,000 miles, with a probable error of 

 only 123,400 miles." Speaking generally, there- 

 fore, one can not be far wrong in calling the 

 earth's distance from the sun 92,500,000 miles, 

 with a light interval of 498 seconds = 8 m 18 s . 



Telescopes. The 28-inch refractor, only 28- 

 foot focus, for Greenwich Observatory, being 

 made by Sir Howard Grubb, has been delayed in 

 its finishing in order to expedite the completion 

 of the 13-inch photographic telescopes for pho^ 

 tographing the heavens, but is well advanced, 

 and will soon be mounted on the same pier on 

 which the 12|-inch telescope has for many years 

 done service at this observatory. Alvan Clark's 

 Sons have closed the contract for the mammoth 

 object-glass of the telescope destined for the 

 University of Southern California, whose ob- 

 servatory is to be on the summit of Wilson's 

 Peak, at a height of 6,250 feet, 13 miles north of 

 Los Angeles. The disks, 41 inches in diameter, 

 have both been received from M. Mantois, of 

 Paris, and the work of grinding begun. The 

 completed lens will have a diameter of 40 inches, 

 and will weigh about 400 pounds. Although the 

 objective is to be 4 inches larger than the Lick 

 glass, the focal length will be the same 56 feet. 

 It would seem that in this telescope will be 

 reached the limit where the gain of light by the 

 augmentation of size must be nearly or quite 

 counterbalanced by the loss by absorption in 



