the lens, or system of lenses, placed at the end of a telescope, microscope, etc., which can be toward the thing. Its function is form a graphic of object, that will be after that viewed because of the eyepiece. Called additionally objective or unbiased lens. See Illust. of Microscope.
In a telescope or microscope, the lens which first gets the rays of light coming straight from object, and collects them into a focus, where they form a picture which can be viewed through eyepiece.
the lens or system of contacts in a telescope or microscope that's nearest the thing becoming seen