collimator Definition
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collimator
noun
- 1. Any device for obtaining a beam of parallel rays of light, used to test the focal length of lenses, etc.
2. Any device, eg a diaphragm made of radiation-absorbing material, used to limit the size and angle of spread of a beam of radiation or radioactive particles.
3. A small fixed telescope that is attached to a larger optical instrument, eg an astronomical telescope, to assist in preliminary alignment, eg to fix the larger telescope's line of sight on a particular celestial body.
