Spectrophotometric Results from the Copernicus Satellite. I. Instrumentation and Performance

Abstract

The Princeton telescope-spectrometer on the OAO spacecraft Copernicus scans stellar spectra with a resolution of about 0.05 Â between 950 and 1450 Â, and twice this in first order between 1650 and 3000Â. The pointing during several minutes is steady within 0'.'02, and the measured photometric precision in the shorter wavelength range is limited only by the statistics of photon counts, with 14-s counts of about 103 on an unreddened Bl star, mv — 5.0, at 1100 Â. In the 1650-3000 Â wavelength range, phototube noise resulting from cosmic rays makes observations difficult on stars fainter than mv — 3.0.