a small telescope attached to a large telescope to use in setting the line of the larger one
optical device consisting of a tube containing a convex achromatic lens at one end and a slit at the other with the slit at the focus of the lens; light rays leave the slit as a parallel beam
例句
用作名词 (n.)
The collimator lighting remains also switched on. 准直仪照明仍然保持开启。
The Collimator projects a reticle to infinity. 准直仪将十字线投射到无穷远。