Guest zidder Posted March 4, 2015 Share Posted March 4, 2015 I have got myself a laser collimator and made a focuser cap. My issue is, when I use the laser to align the primary I get the dot in the middle of the target perfect, then I come to tighten the primary locking screws ( only finger tight ) and the laser moves out of alignment, this happens every time, the only way I can keep it set right is to leave the locking screws undone, this is bugging me big time. Is this usual ? Link to comment Share on other sites More sharing options...
Perkil8r Posted March 4, 2015 Share Posted March 4, 2015 It is quite normal for it to move a bit when tightening yes. How much out it is moving I don't know but I would suggest perhaps letting the locking screws off a little less when adjusting and remember that they don't need to be massively tight. Link to comment Share on other sites More sharing options...
Doc Posted March 4, 2015 Share Posted March 4, 2015 (edited) Are you sure it's not the mirror moving in it's cell. Also a common problem is the actual springs are too weak, they make stronger springs to combat this. I had this problem on my 16" dob and to stop it happening I replaced the springs with stronger ones and always started my collimation with the springs at least 75% compressed and then once collimated finger tighten the locking nuts, they don't need to be tight, just touching will do. Edited March 4, 2015 by Doc Link to comment Share on other sites More sharing options...
Guest zidder Posted March 5, 2015 Share Posted March 5, 2015 Are you sure it's not the mirror moving in it's cell. Also a common problem is the actual springs are too weak, they make stronger springs to combat this. I had this problem on my 16" dob and to stop it happening I replaced the springs with stronger ones and always started my collimation with the springs at least 75% compressed and then once collimated finger tighten the locking nuts, they don't need to be tight, just touching will do. Thanks Mick, My problem is because I bought it second hand I don't know what is right or wrong with it, it is an older model (2008) so I don't know to what extent thing wear on these, I am contemplating stripping it down and starting from scratch replacing anything that is needed but need to understand the mechanics of more first Link to comment Share on other sites More sharing options...
BAZ Posted March 5, 2015 Share Posted March 5, 2015 I only use my lock nuts when transporting it, other wise they stay loose. It saves any problems with moving the mirror like you said. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now