The Astronomy Nexus

Programs like POV-Ray are also good for schematic 3-D renditions, particularly those requiring accurate treatment of reflection and refraction. A Cheshire eyepiece, used to collimate telescopes, is illustrated here.

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In case you're curious about how the reflections in this device work, see the detailed Collimation
FAQ, in particular the cutaway drawing of the Cheshire eyepiece.
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