Skywatcher Startravel lens collimation

[DevonSkies]

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

[F15Rules]

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

[DevonSkies]

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

[F15Rules]

Hope the new one is better!

Dave

[triton1]

I second that

[Dave Lloyd]

My st102 shows perfect stars so I think your next one will be o.k