MISR Integrating Sphere
The main page you just left tells about the calibration of MISR while it is
in orbit around Earth. MISR must also undergo calibration before launch,
while it is still on the ground.
This photograph shows one of the key tools used during this prelaunch
calibration, the integrating sphere. The sphere used for MISR is 65 inches
diameter, and contains 25 light bulbs that can be turned on in various
combinations to achieve different illumination levels. The reason for the
spherical construction is that it results in highly uniform lighting across the
sphere's rectangular aperture (visible in the photograph), large enough for the
MISR sensors' 30-degree field of view. During the calibration process, one
camera views the sphere at a time. The camera sits inside a vacuum chamber to
simulate space, and views the sphere's aperture through a window in the chamber.
Return to: MISR's Sensitivity to Light
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