Upgrade of the SOFIA target acquisition and tracking cameras

摘要

The Stratospheric Observatory for Infrared Astronomy (SOFIA) uses three CCD cameras with different optics for target acquisition and tracking. The Wide Field Imager (WFI with 68 mm optics) and the Fine Field Imager (FFI with 254 mm optics) are mounted on the telescope front ring and are therefore exposed to stratospheric conditions in flight. The Focal Plane Imager (FPI) receives the visible light from the 2.5 meter telescope and is mounted inside the pressurized aircraft cabin at ca. 20°C. It is planned to replace all three imagers' CCD sensors with commercial Andor iXon cameras to significantly increase the sensitivity allowing for tracking on fainter stars. Andor cameras were temporarily mounted on the FPI flange as stand-alone systems to optically measure the telescope's pointing stability and the performance of various telescope sub-systems during engineering flights. Three DU-888 cameras will now be integrated in SOFIA's telescope system, so their image data can be used for target acquisition and tracking. To replace the WFI and FFI, the cameras will also need to be tested under stratospheric conditions, to ensure that they can be operated safely and without degradation of performance. In this paper we will report about the results of the environmental tests with the cameras, the integration of the camera in the SOFIA tracker and the current status of the upgrade project.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.