What is one who, or that which, finds; specifically (Astron.), a small telescope of low power and large field of view, attached to a larger telescope, for the purpose of finding an object more readily called?

finder — One who, or that which, finds; specifically (Astron.), a small telescope of low power and large field of view, attached to a larger telescope, for the purpose of finding an object more readily. (Webster's 1913.)

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