He developed the first reflecting telescope, which featured a concave mirror, a flat mirrow & an eyepiece
He 
used this telescope to compile the first substantial catalog of double stars and, in 
1781,... [DOC] [TLE] [2.0] Refining The Telescope - Vectors [PAR] Dec 1, 2014 ... Newton was not actually the first to try to build a reflecting telescope; the ... 
telescope tube, and a small concave "secondary" mirror mounted on ...