10" Dob collimation - is this right??

[Bendy]

Hi everyone

I'm another Ben from WA with a collimation question...

I've just upgraded from a SW 114/900 to a 10" dob and have just had a go at collimating it with a combo sight tube and Cheshire eyepiece - see attached pic for end result.

As far as I can tell the secondary mirror is centered and tilted correctly. When I adjust the primary mirror I can line up the primary centre mark and the annulus of the Cheshire however both are off centre from the crosshairs.

Do I need to keep tweaking the primary or adjust the tilt of the secondary or something else altogether?

Ben

[Don Pensack]

Ben,
This'll answer a lot of your questions:
http://www.cloudynights.com/page/articles/cat/articles/collimation-and-the-newtonian-telescope-v4-r2599

[Allan_L]

Hi Ben,
With all due respect to Don, this is another take on the same subject that I also find useful.

http://astro-baby.com/collimation/astro%20babys%20collimation%20guide .htm

Sometimes hearing the same thing presented slightly differently helps to clarify it.
Hope this helps.

[Don Pensack]

I like that one, too. Good link.

[Bendy]

Thanks guys, I think I'm on the right track now :thumbsup: