Chandra X-Ray Observatory
Last modified: 7 September 2018

PCAD: Pointing Control and Aspect Determination

Determines the Chandra aspect solution, i.e. the position pointed to by the Chandra X-ray mirror (HRMA) optical axis. The PCAD has a system of gyroscopes to monitor short-term changes, and a 4.25 inch diameter optical telescope with a CCD imager (for longer term corrections and tying to an astrometric reference frame).

See the Proposers' Observatory Guide (POG) for technical details.

Last modified: 7 September 2018
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