Stellar Spectroscopy at 1.1μ

Abstract

This is a progress report on the program of stellar spectroscopy at 1.1 μ reported on by Vaughan and Zirin (1968) and by Zirin (1971). About 450 plates of about 200 stars have been obtained, using a magnetically focused RCA image converter with the 144" and 72" Palomar coudé cameras, giving dispersion of 8 and 17 Å mm⁻¹ respectively. Most of the plates were taken at the latter dispersion and cover about 300 Å. In good seeing a star with J = 3 is obtained in about 90 min. A tube with a fibre optic back-plate is now in use. Cooling such a tube is difficult because the cathode is held at high voltage. By completely insulating the cold box, we may use dry ice cooling, and 2 h exposures, reaching J = 5, may be made with this ITT tube.

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