Reflector
Also called: Newtonian, Newtonian reflector.
A telescope that uses mirrors; the Newtonian, with the eyepiece near the top, gives the most aperture for the money.
Isaac Newton's design uses a curved primary mirror at the bottom of the tube and a small flat secondary mirror that sends the light out of the side. Mirrors have no false colour and are cheap to make large, which is why most big amateur telescopes are Newtonians. They need occasional collimation and some time to cool down.