How do telescopes see faraway things?

A telescope lets distant objects look clearer because its wide lens or mirror collects a much bigger bundle of light than your eye, then focuses that light into a picture. A second lens can spread that picture on your retina, so tiny features look larger and easier to separate.

Some observatories use mirrors wider than buses because huge glass lenses sag under their own weight. In space, Hubble works above our shimmering air, so its pictures are not softened by the atmosphere before the light reaches its carefully curved mirror.