|
Collimation can be adjusted indoors with an artificial star, with the aim being to get the first diffraction ring centered and of even thickness even all the way around. Refractors which don't have push-pull collimation screws might be improved by shimming the focuser.
If the problem is decentering resulting in coma you really need someone experienced to adjust the lenses - very small adjustments to the second or third lens are needed while observing coma at high power and there is a risk of chipping the lenses. Adjustments are made in line with the direction of coma, pushing the lens to reduce the coma.
|