These lasers and the collimation process are based on a concept introduced by Nils Olof Carlin in an article he wrote for Sky & Telescope magazine in January 2003.
Our barlowed lasers achieve the accuracy of Cheshire sight tube collimation with the ease and simplicity of a laser collimator! Standard lasers are subject to minor centering errors on the primary mirror that can be difficult to detect. These minor errors are not much of an issue with longer Focal length telescopes (F5+) but in today''''s'' fast scopes (-F5) this error can make a substantial difference in tack sharp collimation. When using a barlowed laser, it is possible to correct for .5+mm centering errors that make all the difference to achieving superb collimation in a fast scope.
Be aware that to achieve truly tack sharp on any Newtonian type telescope the light path will need to be "closed" using an auto-collimator. This is discussed in the collimation instructions. The auto collimator is built into our 148-Cheshire collimating eyepiece.