The main characteristic of telescopes that defines how much light they can gather is the size of their. . Once light has been collected by the telescope, it must be recorded or displayed by a All the largest telescopes today are telescopes, which use. to collect the light they receive. To protect them from weather and damage, big telescopes are housed in a So that astronomers get the most possible use from a big telescope, it must be located on a mountain or plateau where there is good. Draggable Items aperture cloud cover concavity detector dispersing dome focal length ||||| lenses mirrors reflecting refracting seeing