It will be assumed that 'invested' was a spelling mistake and it should have been 'invented'. Although the refracting telescope is not exactly a new invention, it is one of the newer kinds of telescopes. Created in the seventeenth century by three dutch men, Hans Lippershey, Zacharias Janssen, and Jacob Metius.
The Newtonian Telescope.
One major problem with the refractor telescope used by Galileo was sagging lens.
The YOSCO - much better
lenses
the question is ungrammatical. Restate it.
A refractor
simplest possible telescope
The Emerson 50x is 12mm and the 100x is 6mm.
Galileo
refractor
a refractor or a reflector are two types of telescope.
It gathers more light than a refractor type of telescope can, of the same size.