Checking collimation in a SCT?

[Mr Spock]

This is an idea of what you should be aiming for, with the correctly collimated image at the top.

Even small amounts out can reduce planetary detail so it's worth getting it exact.

[Demonperformer]

If you have a webcam, download a copy of MetaGuide (free) which has a very nice collimation function.

Thanks for that, will download it and have a go.

Here is the link: MetaGuide

[michael.h.f.wilkinson]

I will give the Duncan mask a shot (cheers dunc!), but I have to say that in 15 years of use, my scope always seems to produce out of focus images like the top one in Mr. Spock's post (or very very close). I did seem to get some poorer sharpness on Jupiter, so I will see if I can improve matters. Capella is a suitable target for collimation at the moment.

[EelkoGielis]

I'll try to make one soon for my C9.25" Edge HD