This website is kept for archival purposes only and is no longer updated.
SIGMA / Granat
The SIGMA telescope is the main payload of the Soviet Granat satellite which is entirely devoted to high-energy astronomy and was launched in 1989. The instrument weighs about a metric ton and measures 1.2 m diameter at the base by 3.5 m height. SIGMA consists mainly of a coded mask, a position sensitive detector, various active and passive shielding devices needed to isotate it from background.
The coded mask is a pattern of gamma photon absorbing elements. It is made of squares of tungsten arranged in a pseudo-random pattern. These elements are bonded to a heneycomb plate that supports and stiffens the assembly without hindering the transparancy of the holes in the energy range being studied.
Characteristics of SIGMA
For more info, see J. Paul, Advances in Space Research, Volume 11, p (8)289 (1991) or the SIGMA html page at IKI.
Go to general Coded Aperture Imaging page
These pages have been compiled by Jean in 't Zand. They are intended to provide general information for those interested in coded aperture imaging. Any citations should reference original papers as noted in the bibliography, and requests for further information about any of the papers should be directed to the authors thereof.
October 17, 1995