Paper
11 February 2003 RHESSI Aspect System and In-flight Calibration
Martin Fivian, Reinhold Henneck, Alex Zehnder
Author Affiliations +
Abstract
Precise knowledge of the pointing and the roll angle of the rotating spacecraft is needed in order to reconstruct images with 2 arcsec resolution using the modulation patterns seen on each of the detectors of the bi-grid rotating collimators. Therefore, the aspect system consists of two subsystems of sensors, the Solar Aspect System (SAS) and Roll Angle System (RAS). The transmitted data consists of Solar limb data from the SAS (CCD pixels around the intersection of a Solar image with three linear CCDs) and Star event data from the RAS (CCD pixels induced by passages of Star images over a linear CCD). In order to meet the RHESSI requirements, the reconstructed pointing needs to be ≤ 0.4 arcsec (rms) relatively (≤ 1 arcsec absolutely) and the determination of the roll angle needs to be better than 1 arcmin (rms). Beside of understanding and calibrating each sensor, the error budget on the aspect system requires an alignment of the relevant features of the 1.55 m extended telescope on a micron level. This could be achieved by a combination of on-ground and in-flight calibration.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Martin Fivian, Reinhold Henneck, and Alex Zehnder "RHESSI Aspect System and In-flight Calibration", Proc. SPIE 4853, Innovative Telescopes and Instrumentation for Solar Astrophysics, (11 February 2003); https://doi.org/10.1117/12.460365
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Cited by 2 scholarly publications.
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KEYWORDS
Charge-coupled devices

Stars

Calibration

Sun

Imaging systems

Sensors

Space operations

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