telescope
noun
an optical instrument for making distant objects appear larger and therefore nearer. One of the two principal forms refracting telescope, or refractor consists essentially of an objective lens set into one end of a tube and an adjustable eyepiece or combination of lenses set into the other end of a tube that slides into the first and through which the enlarged object is viewed directly; the other form reflecting telescope, or reflector has a concave mirror that gathers light from the object and focuses it into an adjustable eyepiece or combination of lenses through which the reflection of the object is enlarged and viewed.