Our Astronomical Column

Abstract

SPECTRUM OF NOVA PERSEI.—In the current issue of Comptes rendus (vol. cxxxii. pp. 1542–1544) M. Deslandres gives a third series of observations of the spectrum of Nova Persei as obtained at the Meudon Observatory. Since the previous communication, spectrographs of varying power have been installed for use with the two telescopes of 0.84 metre and 0.60 metre aperture, and both photographic and visual records of the spectrum obtained during the periods of minima, although unfavourable weather has considerably interfered with their continuity. In this later work special attention has been devoted to the expected detection of the principal nebular lines. M. Deslandres states that during the first stages the principal green lines present were distinctly not the nebular lines, but the lines of parhelium, λ492 and λ5015, this being well shown in a photograph taken on March 3. On a plate taken on April 17, however, the measured position of the chief green line was λ5008, but on account of breadth of line the value is of course only approximate. The star was near its minimum brightness on this date. The gradual varying intensity of this line relative to the Hβ line of hydrogen is then described, the details being in close agreement with those already published by other observers.