Is this collimated.

[Shure]

You won't ever be able to, the secondary mirror is too small. This doesn't matter.

Yeah I'd come to realise that after spending the best part of three hours trying to do it

Trying to do it for the first time I was taking astro babys guide as gospel. It was a good learning experience though...

[Jason D]

I gave my 250 dob another crack at fine tuning the collimation tonight. A few things still puzzle me. No matter what I do with the secondary mirror, I can not get any clips in view without the primary being seriously off- centre. The primary is clearly bigger than my FOV through the cheshire.

If you are looking through the cheshire eyepiece then the issue is most likely has to do with the length of the cheshire eyepiece tube. It could be too long for your scope. You might be unable see the clips because they are blocked not by the secondary mirror but rather by the cheshire tube. High end cheshire eyepieces use a variable length tube ( XL COMBO SETS )

Can you see all clips through an empty focuser drawtube?

Jason

[RikM]

You are right Jason, my mistake. You need to take out the Cheshire and the eyepiece adaptor so you are just looking through the 2" drawtube. Then you can see all the clips in a 250PX.

I still don't think there is any need if you line up the Cheshire crosshairs with the dark dot (eyeball reflection).

I do want a Black cat though