Balloon-borne ultraviolet stellar spectrometer.

Description of the design and operation of a balloon-borne telescope-spectrometer system, intended to perform spectrophotometric measurements of the Mg II doublet at 2795 A and 2802 A in stars of visual magnitude 5 or brighter, with a spectral resolution of 0.5 A. It is shown that the system permits considerable flexibility in programming which, in turn, affords great versatility in observational planning and makes the system suitable for detailed studies of specific objects, as well as for survey work.