THE DOMINION ASTRONOMICAL OBSERVATORY AND 
THE BOUNDARY AND GEODETIC SURVEYS 
72-INCH REFLECTING TELESCOPE 
A statement of progress on this new telescope and its observatory 
near Victoria, B.C., is given in the Report of Council. 
STELLAR SPECTROSCOPY 
The past year has been moderately favourable for observing, 
694 stellar spectrograms having been obtained as against 906 in the 
preceding year. 
This reduced number is partly due to greater cloudiness and partly 
to the increased exposure time required for the fainter stars at present 
under observation. The greater number of these are of spectroscopic 
binaries whose orbits are under investigation at Ottawa. 
The orbits of eight of these binaries have been completed and 
published. These stars are ¢ Andromedae, a Trianguli, 4 Persei, 
14 Aurigae, Boss 3323, A Bodtis, B.A.C. 5890, and 12 Lacertae, 
The last of these, 12 Lacertae, deserves special mention as having 
an exceptionally short period, the pair making a complete revolution 
in 4 hrs. 38 mins., only a few minutes longer than the shortest known, 
B Cephei. 
This makes the total number of spectroscopic binary orbits 
determined at Ottawa thirty-seven, a creditable record when the size 
of the telescope is considered, and a greater number than obtained at 
any other observatory. 
STELLAR PHOTOMETRY 
The photographic telescope is now well adjusted and has been 
principally employed in photometric work, the six-inch camera giving 
good extra-focal images over a field five degrees in diameter. Measures 
of the opacity of the extra-focal images of the stars are made on the 
Hartmann Micro photometer. The calibration of the wedge used 
in this instrument has been carefully carried out by means of sensito- 
meter squares and by measures of plates of the Pleiades, and the cor- 
rections for reducing all stars to the centre of the plate have been 
determined. ; 
