Nexstar 11 collimation

[stefski]

Hi All,

I've been having a few collimation issues with my Nexstar 11GPS and was seeking some advice.

My Nexstar needs collimation every time I take it out of the garage. Often by quite a lot. I've also noticed that, sometimes, after it has been pointing at high altitude objects and then moves to lower down objects it loses collimation again:mad:!

I've got Bob's Knobs fitted so its not a difficult job to re-collimate, but should it really be happening this often? I have noticed that the bit that has the 2ndary on (is it called the 'housing'?, the black circular bit) can be pushed in slightly:icon_eek:!? Should this happen? The housing (if that's what its called) is screwed onto the corrector plate tightly btw. Once collimated should I be equally tightening all the knobs so that they can no longer move? Will this stop the housing wobble?

Any advice please..

Stef

[arad85]

I think you should try screwing ONE of the three knobs in relatively tightly and then collimating using the other two. If all three are loose, the mirror can move (or so I'm led to believe) which would cause the collimation issues at higher altitudes...

[stefski]

Cheers Arad...I'll give it a go next time it's clear!

Stef

[brianb]

My CPC1100 has been collimated ONCE, in fact it was almost spot on when delivered. The collimation certainly does not drift about in normal use .... the scope gets carried around but not bumped any harder than can be avoided.

It seems to be fairly common amongst "Bobs Knobs" users that they have difficulty keeping collimation. A time saver they may be, but not if you're continuously recollimating the thing.