The Newtonian Telescope.
The human eye is a refractor, but the telescope could be either refractor or a reflector.
One major problem with the refractor telescope used by Galileo was sagging lens.
The YOSCO - much better
the question is ungrammatical. Restate it.
lenses
A refractor
simplest possible telescope
a refractor or a reflector are two types of telescope.
Galileo
refractor
It gathers more light than a refractor type of telescope can, of the same size.