SOFIA Imaging Systems Tested During Nighttime Operations
Perfect fall weather allowed the astronomers to compare two camera systems, the Fast Diagnostic Camera and the Focal Plane Imager. The Focal Plane Imager, viewing the sky through SOFIA’s telescope mounted in the modified Boeing 747SP’s rear cabin, is used to guide the telescope assembly and to help it track and lock onto astronomical targets. This imager, one of three installed on SOFIA, was tested first and then replaced by the Fast Diagnostic Camera for its tests. The Fast Diagnostic Camera takes rapid exposures of stars to measure the SOFIA telescope’s pointing stability in flight. The camera can also monitor the effects of atmospheric turbulence on the quality of images made with the SOFIA telescope.
Various tracker software checks and validation tests of the camera control software were also performed. The teams' work included a simulation of telescope assembly operations in preparation for flights later this fall.
During a week of nighttime test operations in November 2008, technicians and scientists obtained experience with the telescope while testing a number of functions, including star tracking. Following this, the High-speed Imaging Photometer for Occultation, or HIPO, was installed to support a study of the telescope's optical performance.
The performance of the gyroscope unit on the telescope's assembly system was tested during nighttime work in June 2009. Other system-level software changes were made after similar evaluations with HIPO.
A series of flights are planned for later this fall that will begin with a functional check flight and progress to flights evaluating the aircraft and telescope performance with telescope cavity door gradually being opened.
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