[ 571 ] 
XLYI. 
A CATALOGUE OE BINAEY STAES FOE WHICH CEBITS 
HAVE EEEN COMPUTED. WITH ]S"OTES. Ey J. E. 
GOEE, M.E.I.A., F.E.A.S., Honorary Member of the Liver- 
pool Astronomical Society. 
[Read June 9, 1890.] 
The following list (Tables A to H) of the elements of binary star 
orbits has been compiled from various sources, and includes all the 
orbits I have been able to find. A few orbits may possibly have been 
missed, but the number of such omissions must, I think, be small. 
The stars are arranged in order of Eight Ascension, and the ele- 
ments computed for each, in order of length of period, commencing 
with the shortest found. 
Column 1 contains a number referring to the notes {vide pp. 575- 
599). 
Column 2, the star's designation, denoting the eminent Eussian 
astronomer, E. G. W. Struve, and his equally eminent son, Otto 
Struve. 
Columns 3 and 4 give the Eight Ascension and Declination of the 
binary stars reduced to the epoch 1890-0. I have computed these 
positions from the Greenwich ten -year Catalogue for 1880 for all the 
binaries contained in that Catalogue. The positions of the fainter 
stars, and of the southern binaries, are only approximate, but will be 
found sufficiently close to identify the object. 
Column 5 contains the period in years, the + sign denoting that 
the apparent orbital motion is direct, or in the direction of mcreasing 
position angles, and the - sign that the position angle is (^^creasing. 
Column 6 gives the computed epoch of periastron passage. 
Column 7, the eccentricity {e) of the real ellipse described by the 
companion round the primary star, supposed to be at rest. 
Column 8, the inclination, i or y, of the real orbit to the plane of 
projection, which is a plane at right angles to the line of sight, or a 
tangent plane to the star sphere at the place of the star. 
Column 9 gives the position angle, O, of the line of nodes, reckon- 
ing from the zero of position angles. 
E.T.A. PEOC, SER. III., VOL. I. 2 S 
