5pcs 1.25Inch Cheshire Collimating Eyepiece for Newtonian Refractor Structure Astronomic Principal Calibration Eyepiece

Economical collimation tool ensures that your reflector telescope's optics are in precise alignment. Combination 5inch long sight tube and 1.25inch Cheshire eyepiece. For aligning optics of Newtonian reflectors, Peephole in top and crosshairs at bottom enable precise optical centering. Compatible with 1.25inch telescope focusers or 2inch focusers with a step-down adapter for using 1.25inch accessories