Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

stargazine_ep33_banner.thumb.jpg.75d09b4b1b4e5bdb1393e57ce45e6a32.jpg

DevonSkies

Skywatcher Startravel lens collimation

Recommended Posts

Hi,

I recently bought a SW Startravel 102, which meets my need for a wide field grab and go / travel scope. I initially had some issues with the sloppy focus tube (solved by adjusting the tension screws) and focuser alignment (now adjusted as best I can by loosening and retightening the focuser mount screws).

However, I find that when I perform a star test the collimation still does not seem satisfactory. I have managed to observe diffraction rings on one side of focus, but the central 'blob' (which has a magenta hue) is offset about half way between the centre and the edge of the pattern, and the diffraction rings are similarly offset.

I know this is a sign of imperfect collimation. However, the Startravel does not have a collimatible objective cell. Adjusting the focuser tilt doesn't seem to make much difference apart from shifting the view. I suspect a lens collimation problem because (1) if I loosen and rotate the front cell the diffraction pattern rotates with it, and (2) when using a Cheshire to adjust the focuser alignment it is not possible to get all the reflections to line up perfectly.

I currently still have the option of returning the scope for replacement or refund. So my question is: am I being too fussy? Should I expect good collimation out of the factory on one of these relatively cheap scopes? I realise that this is primarily a wide field scope and poor collimation is mostly an issue at high magnification, but I am a bit of a perfectionist (albeit on a tight budget!).

Has anyone else done a star test on a Startravel 102 or similar scope, and if so how did it look? Any experiences would be appreciated, as I don't want to waste time returning the scope if this is as good as it gets!

Thanks

Ed

Share this post


Link to post
Share on other sites

Hi Ed,

I would return the scope for a replacement or refund.

If the scope has no collimation facility the only way to sort this (assuming that neither of the doublet elements are faulty) is to remove the lenses to try to manually align them- a real pain of a job with the risk of damaging an element.

A scope like this with fixed collimation should be collimated at the factory and fit for purpose! So I'd send it back.

Dave

Share this post


Link to post
Share on other sites

Thanks for the reply. I have now returned the scope, and I am awaiting a replacement.

Share this post


Link to post
Share on other sites

Hope the new one is better!

Dave

Share this post


Link to post
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

By using this site, you agree to our Terms of Use.