Telescopes and Microscopes : a telescope focuses light either by a refracting convex lens (a "refracting telescope") or reflecting concave mirror (a "Newtonian telescope", named after Newton who invented them).
(a telescope; focuses; light; either by a refracting convex lens (a "refracting telescope") or reflecting concave mirror)
a telescope
focuses
light either by a refracting convex lens (a "refracting telescope") or reflecting concave mirror