Credit: IKI/CEA
Granat and the mask of the Galaxy
GRANAT was a
Russian astronomical observatory satellite dedicated to X-ray and gamma ray
astronomy. GRANAT operated from 1989 to 1998 and was a collaborative
observatory which included instruments from a number of European
countries. The SIGMA telescope on GRANAT was a coded
mask instrument provided by France. Coded-mask telescopes are a bit
unusual in that they don't have imaging optics (like a lens or mirror) to
produce images. Coded-mask telescopes consist of a thick patterned mask in
front of the detector; from the variation of the intensity of the light
falling on the detector, and from the known mask pattern, an image of the
observed object can be reconstructed. A SIGMA image of the galactic center
is shown above. This image is one of the deepest high energy images of the
galactic center ever obtained.
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Page Author: Dr. Michael F.
Corcoran
Last modified April 30, 2001
