Upper atmospheric temperatures from Doppler line widths-III. Observation of the OI dayglow emission at 6300 Å

Abstract

In principle, a spectrometer on the Earth's surface, of sufficiently great resolving power, is capable of detecting dayglow emission. A detailed report is given of a series of measurements conducted between August 1962 and July 1964, at Saskatoon, in which a doubleetalon Fabry-Perot spectrometer was employed in a search for the atomic oxygen dayglow emission at 6300 Å. It is demonstrated that even with high resolution it is difficult to extract the emission line from the Fraunhofer structure of the Rayleigh scattered background light. Only by subtracting alternate spectra of Sun and sky were unambiguous results obtained. The observed brightnesses were approximately 10 kR, and the temperature deduced from the Doppler line width is estimated to be in excess of 1200°K. © 1965.