THE USE OF A PLANE GRATING IN STELLAR SPECTRO-SCOPY.—In No. 5, vol. vi., of the Journal of the Royal Astronomical Society (Canada) there is an interesting note describing some preliminary tests, made ...

WE have recently obtained a series of spectra of the night sky in the wave-length region 1–2 µ. A lead sulphide cell was used as the detector in a grating spectrograph normally used for photographic ...