UIT Technical Summary

Principal Investigator: Theodore P. Stecher
Developing Institution: NASA Goddard Space Flight Center
Telescope Optics:      Ritchey-Chretien
Aperture:            38 centimeters (15 inches)
Focal Ratio:          f/9
Field of View:        40 arc-minutes
Angular Resolution:    2 arc-seconds
Wavelength Range:      1,200 to 3,200 angstroms 
Magnitude Limit:       25
Filters:             2 filter wheels, 6 filters each
Detectors:           2 image intensifiers with 70-mm film,
                   1000 frames each, IIaO astronomical film
Exposure Time:        Up to 30 minutes per target
Weight:             474 kilograms (1,043 pounds)
Dimensions:          81 centimeters (32 inches) diameter
                   3.7 meters (12 feet) length

Designed at NASA's Goddard Space Flight Center, the Ultraviolet Imaging Telescope (UIT) is a key instrument in efforts to obtain deep, wide-field ultraviolet (UV) images of the sky. UIT uses a 38-centimeter (15-inch) diameter f/9 mirror to focus images on single frames of 70-millimeter film and has the largest field of view of any sensitive UV imaging system planned for flight this decade.

UIT has a 40-arc-minute field of view, with the 38-centimeter primary mirror reflecting light to a secondary mirror attached to a sensitive image motion compensation system. This allows the instrument to achieve an angular resolution of 2 arc-seconds. Reflected from the secondary mirror, the light passes through two filter wheels containing six filters each. These different filters, used singly or in combination, allow specific regions of the UV spectrum to be isolated for quantitative energy distribution studies.

The light then enters one of two image intensifiers/film transport units. The image intensifiers amplify and convert the ultraviolet light into a visible image that can be recorded by the photographic film. Each unit contains 1,000 frames of IIaO astronomical film. Covering the spectrum from 1,200 to 3,200 angstroms, the UV camera is sensitive enough to record a blue star of 25th magnitude during a 30-minute exposure. Developed after the mission, each frame of film is digitized to form a 2,048 by 2,048 pixel array for computer analysis.

The Ultraviolet Imaging Telescope gives a more general description of UIT's capabilities.

Further information can be found on the UIT home page.