Optical Sight (COAS)


	On this page: Overall View LM-6 View Lamp Assembly Handbook Illustration

Apollo Lunar Module Crewman Optical Alignment Sight (COAS) for aiding the astronaut in rendezvous, docking, and navigation.
Displays a graduated circle reticle that appears to be at infinite distance.
Could be mounted and set for use at the left window (“LW”), overhead window (“OW”), and right window (“RW”).
Large knob controls light intensity; small knob is pulled to rotate the barrel to set the window position.
A similar unit was used in the Command Module, and a follow-on design is used in the Space Shuttle.


	This version (-0009) included a neutral density (dimming) filter that reduced the maximum lamp brightness. On the Apollo 9 flight, the reticle image was not visible against the bright sunlit Command Module. The brightness level was increased on later versions (-0021, -0025), used on Apollo 10 and later, with the removal of the built-in filter in favor of an external detachable filter.


	1.55 lbs. (0.71 kg)

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Similar COAS mounted above the left window in the Apollo 12 Lunar Module. (NASA photo)

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