Hubble
Space Telescope Backup Mirror
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This is one of two nearly identical main mirrors built by
Corning for the Hubble Space Telescope. The mirror installed
on the Hubble was finished by Perkin-Elmer Corporation using
computerized techniques. This backup mirror was finished by
Eastman Kodak, which used conventional optical techniques
to shape and polish the mirror.
Backup mirror transferred from NASA, courtesy of Kodak
Test cradle transferred from NASA, courtesy of Raytheon |
Facts:
- How big
is it? This mirror measures 2.5 meters (98 inches) across and
weighs 748 kilograms (1,650 pounds). The useable surface of
the mirror in the Hubble was slightly smaller-about 2.4 meters
(94 inches)-because the mirror mounting covered the outer edge.
- Why doesn't
it look like a mirror? This mirror was never used, so it never
received a reflective coating. The mirror in the Hubble was
coated with a thin layer of aluminum and also overcoated with
magnesium fluoride, so it could better reflect ultraviolet light.
- What is
it made of? The mirror is made of Corning ultra-low expansion
glass. The front and back surfaces are fused to a lattice core
and to the inner and outer bands, creating a sturdy but lightweight
structure.
Behind
The Scenes: Bringing The
Backup Mirror to the National Air and Space Museum
Other Featured
Artifacts in this section of the exhibit:
Hubble Space Telescope Wide-Field/Planetary
Camera & CCD
Penzias and Wilson Pigeon Trap
High Resolution Imager (HRI)
Also
In the Museum:
Hubble Space Telescope (Test Vehicle), on display in the "Space
Race" exhibition.
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