This is a flight test spare of a far ultraviolet photometer and associated collimator of the type flown on Aerobee sounding rockets by the Aeronomy group at the Naval Research Laboratory. This potted flight test spare used for geocoronal studies dates back to about 1972.
As part of its studies of the upper atmosphere, the Naval Research Laboratory sent specialized instruments to extreme altitudes on Aerobee sounding rockets. Maximum altitude for the rockets was close to 230 kilometers. This far ultraviolet photometer is representative of those sent up in rockets around 1972 for observations of the Earth's nightglow, called the geocorona. This photometer was designed to detect the ultraviolet radiation emitted by hydrogen at the Lyman beta wavelength. A collimator to exclude stray signals guards the aperture of the tube.
This instrument was transferred to NASM by NRL in March 1986.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.