This paper describes installation of a long wavelength infrared (LWIR) acquisition camera on the Starfire Optical Range (SOR) 1.5 meter telescope, and reports initial performance results. This camera was designed for acquisition of satellites night or day, irrespective of target illumination. The camera may also have wide field-of-view astronomy applications. The optical design for this LWIR acquisition camera maps a 128 X 128 pixel Si:As impurity band conduction detector array onto the two milliradian telescope scene. A warm, aspheric germanium lens images the f/217 telescope beam onto a cold field stop, and the telescope pupil onto a cryogenic chopping mirror. The cryogenic chopping mirror has an opaque mask which serves as a radiation stop. A second, cooled, aspheric germanium lens reimages the field stop onto the detector array. Operation of the camera over the 7 - 24 micrometers detection band of the array is possible by replacing the interference filter and zinc selenide vacuum window. Problems and solutions pertaining to integration of the camera and cryocooler system on the telescope are described. Initial performance data reported include: optics/array radiometry, telescope background measurements, cryocooler induced telescope jitter measurements, and cryogenic chopping mirror characteristics.

Date Published: 6 June 1995
PDF: 15 pages
Proc. SPIE 2475, Infrared Detectors and Instrumentation for Astronomy, (6 June 1995); doi: 10.1117/12.211261

Published in SPIE Proceedings Vol. 2475:
Infrared Detectors and Instrumentation for Astronomy
Albert M. Fowler, Editor(s)