Clementine Near-Infrafed Camera (NIR)

The NIR camera uses a catadioptric lens with a 256x256 indium antimonide (InSb) FPA mechanically cooled to cryogenic temperature. The FPA operated at 70 plus-or-minus 0.5 K at the Moon and showed excellent stability over the more than 500 hours of operation in space. The lens design features all ZnSe refractive elements with a relay to provide an external pupil for 100% efficient cold shielding. This lens design was chosen for image quality and focus stability. Wavelength range was constrained by the optics and the InSb response to somewhat less than 1.0 to 5.5 microns. Six wavebands were selected by the NASA advisory committee, all falling well inside this range.

Camera electronic programmable variables allow 4 integration times, 5 bits of gain, and 8 bits of offset. Gain states are spaced approximately evenly from 0.5 to 36 factors of voltage multiplication. Offset is subtracted before gain is applied with 0 V to full well range that can be set in 1/255 full well increments.