This is the flight design verification unit (FDVU) of the white light coronagraph, one of the principal Apollo Telescope Mount (ATM) instruments on Skylab. It studied the sun's outer atmosphere, its corona. The coronagraph photographically monitored the brightness of the solar corona over a wavelength range from 3500 to 7000 Angstroms. Prior to building the actual flight unit, Ball Aerospace Systems of Boulder, Colorado, constructed two working models of the telescope, an engineering prototype and the FDVU. The FDVU was used at the High Altitude Observatory (HAO) at the National Center for Atmospheric Research to test new instrument concepts. It may have flown once in a balloon-borne test. In 1982 the engineering prototype was transferred from the Marshall Space Flight Center to HAO. The latter then transferred the FDVU to NASM in March 1983.
3-D (Container, Coronagraph ATM): 349.9 × 83.8 × 129.5cm, 237.7kg (11 ft. 5 3/4 in. × 2 ft. 9 in. × 4 ft. 3 in., 524lb.)
3-D (Weight includes original container): 315 × 53.3 × 55.9cm, 617.8kg (10 ft. 4 in. × 1 ft. 9 in. × 1 ft. 10 in., 1362lb.)
Mixed lightweight metals, glass, electronic components; Aluminum, Copper, Epoxy, Kapton (Polymide), Rubber (silicone), Plastic, Steel, Gold Plating, Glass, Acrylic (Plexiglas)