The Celestron Cheshire Collimation Eyepiece is ideal for precise collimation of Newtonians and helpful for aligning Schmidt-Cassegrains. This special eyepiece fits into 1ΒΌ-inch focusers or diagonals.
Alignment is easy using the small opening on one end and thin cross hairs at the other end. The collimation eyepiece is more accurate than the simple Collimation Tool.