Focus

[richard omeara]

I have a c-11 sct with a gstar ccd.I am having probs with focus.The scope has a 2" crayford focuser only.Am i better of useing the original 1.25" focuser to bring the ccd closer.Or may be a focal reducer?THANKS ALL

[jjjnettie (Jeanette)]

Richard,
I'd repost your question in the Cameras, Photography and Imaging Equipment section.
You have a better chance of the right people reading your post.
Cheers

[Zuts]

Originally Posted by richard omeara

I have a c-11 sct with a gstar ccd.I am having probs with focus.The scope has a 2" crayford focuser only.Am i better of useing the original 1.25" focuser to bring the ccd closer.Or may be a focal reducer?THANKS ALL

Hi,

Usually people use the original 1.25 to get the mirror roughly focussed, then use the crayford for fine focus. Doing it this way avoids a lot of focus flop which is why the crayford is installed.

Also, I have never seen a Celestron SCT without the original focusser, which moves the whole mirror; so am a bit confused when you say the scope has a Crayford only?

Cheers
Paul

[bmitchell82 (Brendan)]

Im with you there Zuts... to my knowledge sct's move the whole mirror... the only telescope that i have seen that moves like a reflector is the old 1960's Cassigrain Carl Zeiss-Jalna that curtin owns. but then again it isn't a SCT.... the Meade moves the whole mirror both in Snr and Jnr! (5" etx 12"LX200)