The variability of this star was discovered by Madame Ceraski from plates made by Blakjo at Moscow, and was announced in A. N. No. 3953. The photographs indicated a variation from the ninth to the eleventh magnitude ...

The variability of ST Ophiuchi was discovered at Harvard from an examination of31 photographs taken during the interval 1893-1904. Professor Pickering announced that the light variation was short duration, evidently about ...

"The present discussion is based on 51 plates taken by Dr.Baker and the writer with the 5-inch camera during the period from July 1914 to October 1915. These plates where exposed about 1.5 mm. outside of focus, and were ...

Spectrum analysis may perhaps be said to date from the year 1666 when Sir Isaac Newton discovered that rays of light of different colors are of different refrangibility. Later he discovered that a beam of white light coming ...