130 



ASTRONOMY FOR 1889, 1890, 

 PROPER MOTIONS. 



Professor Boss has published in the Astrouoiuical Journal the proper 

 motions of L'O.") stars of the Albany zone (+ 0^ 50' to + 5° 10'). 



Jn the lluUdui Antr<)nomu[ue lor March, 1800, is a most useful cata- 

 logue, compiled l)y Bossert, of all stars whose proper motion is known 

 to exceed O."o0. They are thus distributed : 



DOUBLE AND MULTIPLE STARS. 



Some very elegant and simple formula' for determining the true orbit 

 of a binary star, originally published in Russian, have beeii brought 

 out by Professor Glasenapp. 



I Scorpii. — llerr Schorr has made a study of the motions in this 

 triide system by methods similar to those employed by Dr. Seeliger on 

 C Cancri. The star is known as - 1098, the magnitudes of its compo- 

 nents being A =3.9, B = 5.2, C = 7.2. 



Tj Ophiuchi has been divided into two nearly equal components by 

 Burnham with the 36 inch Lick telescope, and he thinks that it will 

 l>rove to be a binary of short period. He has also found comi)anions 

 for Aldebaran, y ()assiopeia% and ^7C.\gni, and has been able to sepa- 

 rate and measure a comi)anion to the principal star in the pair e Ilydr.T, 

 the existence of which was susi)ected by previous observers. 



Plioto,ura{)hs of the spectrum of Spica have put beyond question the 

 reality of its motion in the direction of the line of sight. Dr. Vogel 

 has deduced from observations of 1889 and 1890 a period of revolution 

 of about 4 days. 



PHOTOMETRY. 



The results ot observations made with the meridian jihotometer of 

 the Harvard observatory by Prof. E. C Pickering and INIr. Wendell 

 <lnring the years 1882-1888, have appeared as volume 24 of the Harvard 

 Annals. The principal work done with this instrument was "the de- 

 termination of the magnitudes of a sufticient number of stars con- 

 tained in the Dnrchmnsrcruiig, and distributed with a[)i)roximat(^ uni- 

 formity, to serve for future estinuites or measures of magnitude, and 

 to enable j)revious estimates to be reduced to the photometric isc^^l^," 



