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22 October 1999 Solar Aspect System (SAS) for the High-Energy Solar Spectroscopic Imager (HESSI)
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The HESSI SAS is a set of three Sun sensors, which shall provide high bandwidth information on the solar pointing of the rotating spacecraft. The precision of <EQ 0.4 arcsec relative is necessary in order to obtain the HESSI imaging resolution of 2 arcsec; the absolute accuracy of 1 arcsec is required for comparison with other measurements. Each SAS is based on focusing the Sun through a narrow bandwidth filter on to a 2048-element x (13(mu) )2 linear CCD. A digital threshold algorithm is used to select N pixels that span each solar limb for inclusion in the telemetry. Determination of the 6 limb crossing locations provided by the 3 subsystems defines the position offset of the Sun in the rotating frame. In this paper we describe the mechanical and electronic configuration of the SAS FM and the results of the first test measurements.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Reinhold Henneck, Jacek Bialkowski, F. Burri, Martin Fivian, W. Hajdas, A. Mchedlishvili, P. Ming, Knud Thomsen, J. Welte, Alex Zehnder, Brian R. Dennis, Gordon J. Hurford, David W. Curtis, and David H. Pankow "Solar Aspect System (SAS) for the High-Energy Solar Spectroscopic Imager (HESSI)", Proc. SPIE 3765, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy X, (22 October 1999);


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