You're seeing the edges of the foils in many, many arcs, like that.
Edge view of the foils in the mirror.
Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.
The Imagine Team
Acting Project Leader: Dr. Barbara Mattson
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