Original flight object, the Ultraviolet Imaging Telescope (UIT) was one of the major components of the ASTRO mission that flew twice in space, first on Columbia from 2 - 10 December 1990, and then on Endeavour from 3 to 17 March 1995. UIT is an F/9 Ritchey-Chretien reflecting telescope with a primary mirror 38 cm. in diameter. Light could be directed to either of two magnetically focused multi-stage image intensifiers that produced images that were then photographically recorded on 70-mm Kodak IIa-O spectroscopic film and stored for physical retrieval at the end of the mission. The two detection systems covered both the near-ultraviolet and far-ultraviolet wavelength ranges from 1200 to 3300 Angstroms, and the optical system produced 40 arc minute fields, just a bit larger than the full Moon. The two missions produced almost 1600 exposures of about 260 target fields, and these are available in various electronic formats for general use from a NASA website.

UIT was built by the Laboratory of Astronomy and Solar Physics (LASP) at NASA's Goddard Space Flight Center. Theodore P. Stecher led the project. UIT recorded a wide range of astronomical sources including nebulae, supernova remnants, globular clusters, galaxies and clusters of galaxies. When a third flight of ASTRO was not funded, the UIT and its sister instruments, including the Hopkins Ultraviolet Telescope and the BBXRT telescope, were retired. UIT and HUT were transferred to the National Air and Space Museum in 2005.