Is my collimation acceptable?

[IWatchStars]

Hi,

I attempted to collimate my nexstar 127 maksutov while it  already was collimated(determined with star test). I think I had loosend it to much becaus the rubber seal between the backplate and the tube fell off on one side.

See picture:

This scared the hell out of me. I also managed to un-collimate the scope. Eventually I managed to collimate it again and this is the result:

Does the collimation look acceptable on these pictures? I know it's not perfect, I tried but failed to get it perfect.

[Dave In Vermont]

The collimation looks fine. That doesn't concern me here - you loosening the back of the scope from the tube, on the other hand, is a cause for concern.

Did you manage to get it all back together alright? The collimating screws only need a slight movement - 1/4 turn at a time. You really need to be like a kitten moving these bolts. Not a gorilla. Maksutov's are known to maintain their collimation very well.

Here are some, hopefully, better instructions for a Mak:

http://www.company7.com/library/orion/Inst_makcasscollim.pdf

And a local entry:

http://stargazerslounge.com/topic/176741-collimating-maksutov-cassegrain/

Another from the web:

http://www.robincasady.com/Astro/collimation/

And, finally, where would we be without youtube?

I hope all goes well. Please keep us informed?

'ta,

Dave

[IWatchStars]

Yes I did manage to get the rubber seal to stay in it's place, so I think the back plate isn't loose anymore. I could try to make it even tighter, but I dont know if thats necessary, and obviously doing that will ruin my collimation.

The manual says the little screws are for pushing and the big screws for pulling. This is a bit confusing. Wont every screw pull when You loosend it and push when You tighten it?

[IWatchStars]

And thank You for the better tutorials, I will read them when I'm home.

[IWatchStars]

By the way: the big screws(those are the ones that keep the back plate in it's place I'm assuming?) are pretty tight.

[Stub Mandrel]

If its like my reflector, one set of screws (the lock screws) pushes against the mirror mount when tightened, the other pulls the mount back against these screws.

There are springs to keep the tension on when you loosen off the lock screws allowing you to adjust with the - wait for it - adjustment screws.

You then retighten the lock screws to keep everything in its place.

If you don't have the springs, you need to loosen one screw by a little bit then tighten the other to make each adjustment. If they are very stiff you may be trying to adjust without loosening the lock screws, or by further tightening the lock screws.