Collimator

Collimator, a word falsely derived, and more correctly written collincator. In a corrupt Latin MSS. the verb collimare was found in the sense of to put in line with, to aim at. Hence the word collimator, which is a term used in astronomy. The collimator is an auxiliary telescope, which enables the deviation between the true axis and the observer's line of sight to be ascertained, and so accuracy to be secured. In the spectroscope the collimator is a slit in the object-glass, by which the rays pass from the prism.