Jump to content




Skywatcher 200p needs Collimating and Mirrior has mark

Recommended Posts


Ive owned a Skywatcher 200p not had much sucess with it (see previous posts)

Anyway the latest is...

1. Missus put 2 EP caps on the main scope dust cover and when i lifted it the caps fell in the scope - i got them out but theres 2 small black marks on the primary mirror - look like bug splats. Should I be concerned ?

2 I looked at a star tonight and de-focused - The star was at the bottom right of the rings - Could the scope need collimanating ?

Thanks for your help all

Link to comment
Share on other sites

The good news is it sounds like the mirror probably isn't damaged, otherwise the diffraction pattern would be very messy, but yes, it sounds like you may have to collimate it, the star should be at the centre of the diffraction pattern in a well collimated scope. I've seen a couple of good collimation guides on this forum, and with a relatively fast scope it's something you'll need to learn anyway, good luck!

Link to comment
Share on other sites

Hi, I did a similar thing about a year ago, dropped an eyepiece dustcap down the

tube of my S.W. 200. I thought it may have left a tiny mark on the primary but

wasn't sure.

The mirror was getting really grotty looking anyway, so out it came for a clean.

No problem, the tiny mark, plus all the other crud, came off with a very careful

wash. The mirrors have a hard overcoating, which is actually quite tough, but

I would definitely still be careful. Mirrors can look awful, but perform well, so don't

rush to clean it.

When star collimating, the defocused star should be in the centre of the field of view.

Cheers, Ed.

Link to comment
Share on other sites

Just as a guide - Keele Uni observatory have a 24" mirror on a massive scope - it has a chunk the size of a 2" equilateral triangle out of it and it still functions fine - look at the site for examples of pics taken.

The dust caps might have made a tiny mark but I can't see them damaging it - finger print smears where you took them out will cause more reduction in the views. You should collimate it though - this will need doing routinely every one or two sessions anyway ;)

Link to comment
Share on other sites

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 account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.