The magnification is the ratio of the apparent sizes of the object. For example, if the angular size of the object is one arc minute and through a telescope, its apparent size becomes 30 arc minutes, then we say the magnification is 30. The magnification of any telescope can be changed very easily (by changing the eyepiece). Even for the largest telescopes, the magnification is seldom over 500, usually between 100 - 200. Thus, large telescopes do not magnify more, they only show brighter and sharper images.