An Ultraviolet Rocket Stellar Spectrometer

The Ultraviolet Rocket Spectrometer (UVR) was developed to measure stellar spectra in the wavelength interval 1100 A to 4000 A. The UVR consists of a 33 cm Dall-Kirkham telescope which provides input to a spectrometer utilizing a plane grating in convergent light. The f/#11.9 system is such that the apparent coma of the plane grating is compensated for by the coma of the tilted spherical spectrometer mirror. Two exit slits are located at compromise focal positions and cover the total scan of 2900 A in two bands with a central overlap of approximately 1300 A. Spectral scan is cam operated and grating position is indicated by a marker generator related to cam rotation. The absolute response function of the flight unit is established by the simultaneous exposure of calibrated photomultipliers (PMT) and the UVR to the same monochromatic beam of collimated light. Analyses of spectra recorded in the laboratory indicate performance consistent or better than the 3 A equivalent width of the UVR exit slits.