Cheshire eyepiece / 1.25 inch (wire reticle with long adjustment tube)

Cheshire eyepiece / 1.25 inch (wire reticle with long adjustment tube)

Ideal for collimating Newtonian telescopes, but also useful for adjusting Schmidt-Cassegrains
Fits in any 1.25" eyepiece mount
Mirror alignment is not a problem if you use the small opening on one end and the crosshairs on the other. The Cheshire eyepiece is more accurate than a simple collimation tool.