1st attempt with a cheshire

[Nova]

Just a quckie really. Looks like cloud is going to ruin play tonight but have spent the last half hour practicing with my cheshire. When I look into it I can see the cross hairs and down on the primary I'm seeing the centre circle and the reflection of the cross hairs. I have no problem aligning the relection of the cross hairs to the centre circle but the actual cross hairs do not line up with the centre circle and the relection of the cross hairs. What is this telling me? Am I only meant to align the reflection or should all 3 line up?

[Bizibilder]

Have a read of Astro Baby's collimation tutorial:

Astro Babys Guide to Collimation

It is very clear and takes you through the proces step by step with diagrams and hints.

[Nova]

yes, thanks bizibilder. i went straight to the collimation bible as soon as i noticed it but couldnt find referance to this particular problem. Im wondering it the secondary is a tad out which is why i cant line them up but using a colli cap everything looks as it should.

Have added a picture that shows the problem. it looks slightly worse in the pic than it actually is probably due to the camera angle

[umadog]

Clearly something's off. Here is the procedure for a Cheshire/sight-tube combo tool:

John Reed Home Page Collimation - Cheshire

Also, I would recommend looking at some threads on Cloudy Nights, which are very good. Join if you have to.

Telescope Reviews: Useful info about secondary mirror alignment

Telescope Reviews: Concise thread about autocollimators+improvements

[Nova]

That first link helped a lot thanks Umadog, it has probably just made my collimation cap redundant. Well worth a read for anyone that is having problems.

Looks like its back to the start for me and some secondary adjustment is required.