Image of the day

From the
ATWB Customer Gallery

Disco Inferno

My Account

New to Astromart?

Register an account...

Need Help?

SCT Collimation Issues

Started by Brisley, 11/15/2003 08:09AM
Posted 11/15/2003 08:09AM Opening Post
I was collimating my 1980 C-8 last night and have an issue with the image that I am trying to understand where the problem may be.
I get a good circle pattern inside and outside of focus except I also see a cone of distortion coming from the center to the bottom, almost like a parabola. If I shift to the other side of focus, a distortion appears on top of the image. Not the eyepeice, as I see this with different eyepieces and with and without the disgonal and it does not rotate with the eyepiece or my head rotation. Scope was outside for about 2 hours, so this is not thermal. Scope has not been used heavily for past 6-8 years, kept in its box.

Any ideas what I am seeing and where it may be coming from?
Is this something that will appear if the optical train is not perfectly centered, or am I dealing with some sort of flexure issue or optical problem?

(Getting this scope collimated cleanly and understanding what to do is a prep for my 1972 model being rebuilt/recoated completely.