ASTRONOMY, PROGRESS OF, IN 1893. 



The negative shows a double tail, one, about a 

 degree in length, pointing east, the other, of half 

 a degree, turned toward the north. 



Comet c, 1893 (Brooks). On the morning of 

 Oct. 17, Prof. W. R. Brooks, Director of Smith 

 Observatory, Geneva, N. Y., discovered a fairly 

 bright comet in right ascension 12 h 21 m ; decli- 

 nation north 12 55' ; having a short tail and 

 moving slowly northeasterly. Its discovery posi- 

 tion is quite close to that of his comet (g) of 1892. 



Time of perihelion passage, 1893, Sept. 20-552, 

 Berlin mean time ; longitude of node, 175 19-3' ; 

 node to perihelion, 350 40'2' ; inclination, 130 

 13-7' ; log. perihelion distance, 9-91968. 



These elements resemble those of comet 1864 1. 



Barnard's Photographic Comet. The hastily 

 calculated elements of this body, as published 

 last year from observations of three one-day in- 

 tervals, are, as might be expected, slightly in 

 error. The following are by Prof. Krueger, of 

 Kiel, Germany, who, from observations of Oct. 

 16, 20, and 25, has obtained elliptic elements 

 that indicate a period of 10-4 years : 



Perihelion passage, Oct. 20-5, Berlin mean 

 time ; mean anomaly, 355 27'9' ; node to peri- 

 helion, 167 41-9' ; longitude of node, 204 38'9' ; 

 inclination, 32 11-9' ; angle of eccentricity, 43 

 38-6' ; perihelion distance, 1-9904 ; daily motion, 

 341-680". 



These elements bear too strong a resemblance 

 to those of Wolf's comet of 1891 to be regarded 

 as accidental. 



New Star in Auriga. No pains have been 

 spared to make the spectroscopic study of this 

 new star, discovered on Feb. 1, 1892, by Rev. F. 

 D. Anderson, of Edinburgh, Scotland, as com- 

 plete as possible. Almost every spectroscopist 

 in the world has busied himself with its spec- 

 trum, and from all came the same story of a bril- 

 liant array of bright lines. While this feature 

 of its spectrum was not unexpected, one alto- 

 gether unique was simultaneously observed at 

 several observatories, viz.. the bright lines were 

 attended by dark companion lines on their more 

 refrangible sides. Three of these lines attracted 

 much attention everywhere because of their in- 

 timate connection with the suspected physical 

 constitution of the star, and are, first, the bright 

 line near b, the less refrangible edge of the hydro- 

 carbon band ; second, the line near the chief 

 nebular line wave length 5,006 ; and, third, that 

 one near the pair of chromospheric lines wave 

 lengths 4,923 and 4,921. 



On Feb. 22 Dr. Huggins discovered a com- 

 plete series of bright lines in the ultra-violet 

 identical with those found by Prof. Hale in the 

 solar chromosphere, but each with its dark com- 

 panion line, as if the outburst of the light of the 

 star were caused by a vast chromospheric dis- 

 turbance. Then arose the question whether the 

 wideness of the lines was attributable to a single 

 or multiple origin. The two strong lines at F 

 and G were certainly divided by a faint, dark 

 line near the center of each. Measurements of 

 the separation of the F line of hydrogen gave, 

 with reference to the earth, a velocity of reces- 

 sion of 230 miles a second and a velocity of ap- 

 proach of 320 miles a second to the dark lines. 



The star has exhibited- several fluctuations of 

 brightness, having declined on April 22 to the 

 sixteenth magnitude, while on Aug. 19 it had 



attained to the tenth magnitude, its spectrum 

 then being that of a planetary nebula. From 

 March 13, when it was of the eighth magnitude, 

 to April 26, when it had faded to the sixteenth 

 magnitude, its decrease was perfectly uniform, 

 and it was assumed that it would thus gradually 

 decline into invisibility even with the Lick tele- 

 scope, when suddenly it brightened, as above 

 stated, to a nebula with a nucleus of about the 

 tenth magnitude, as observed by Barnard. The 

 catalogue name of the star is T Auriga, but it 

 is generally mentioned as the nova in Auriga. 

 Strictly speaking, it ought not to be classed 

 as a variable but rather as a temporary star. 

 Interest attaches to the statement that on Dec. 

 10, 1892, the nova was photographically three 

 magnitudes fainter than visually. 



Nova Auriga is the sixth temporary star that 

 has appeared during the past forty-four years. 

 The list follows : 



On April 28, 1848, near Eta Ophiuchi ; May 

 21, 1860, between Alpha and Beta Scorpionis ; 

 May 12, 1866, near Epsilon Corona Borealis ; 

 Nov. 24, 1876, near Rho Cygni ; Aug. 31 (?), 1885, 

 in center of the great Andromeda nebula ; Jan. 

 31, 1892, near Chi Auriga. 



The Auriga nova will always be memorable 

 as the first temporary star to be subjected to 

 thorough spectroscopic examination. The dou- 

 bling of the spectral lines was a fact of vast sig- 

 nificance, showing conclusively that two bodies 

 moving in opposite directions were concerned in 

 the production of the compound spectrum. The 

 velocities above mentioned are unprecedentedly 

 great, but their real motions may have been, and 

 probably were, greater, inasmuch as the spec- 

 troscope takes no cognizance of lateral motion, 

 and it is highly improbable that they were mov- 

 ing exactly in the line of sight. 



Though we are greatly indebted to the spec- 

 troscope for its revealings regarding this " new 

 star," yet it has failed to make known whether 

 all temporary stars attain their sudden brilliance 

 from the same cause a question which the next 

 one will doubtless settle. 



Algol System. By means of the elaborate 

 discussion of nearly 700 observed minima of Al- 

 gol (Beta Persei), Dr. Chandler has propounded 

 a highly interesting theory, explanatory of some 

 of the inequalities observed in this variable star. 

 From these discussions he has resolved these in- 

 equalities into two principal components, one 

 with a period of about 141 years and a co-effi- 

 cient of 173-3 minutes, the other with a period of 

 37-7 years and a co-efficient of 18 minutes. He 

 ascribes these effects to . differences in the times 

 of light transmissions from the various parts of 

 a large orbit described by Algol and its close 

 dark companion around another dark and more 

 distant star. This orbit, which is sensibly cir- 

 cular, lies in a plane inclined about twenty de- 

 grees to our line of sight, completing a revolution 

 in 131 years, at a distance equal to that of the 

 planet Uranus from the sun, or nearly 1,800,000,- 

 000 miles. To the extent of 149 minutes (the 

 time required for light to pass across its fore- 

 shortened radius) are the eclipses of Algol alter- 

 nately accelerated or retarded, as the star ap- 

 proaches toward or recedes from the earth. The 

 star is timed to reach that point of its orbit near- 

 est the earth within 6 or 7 years, when a maxi- 



