C9.25 HD: external focuser? AO?

[nmontec]

Hello Everybody,

do you know of anyone using the C9.25 HD together with one or both of the following?

- an external focuser on the C9.25 HD?

- the SX-AO?

Thanks in advance

Nicola

[northcanadian]

Hi Nicola:

I have a Celestron 9.25 SCT and use a Crayford style (Anteres) focuser on the visual back....works great!  I also have a motorized accessory that fits onto the scope focus knob, but I don't really use it lately...just the other.

Cheers

Roger

[nmontec]

Hi Roger, thanks for your answer. I guess that the SCT and EDGE HD have different backfocus though...

[Earl]

Hi Roger, thanks for your answer. I guess that the SCT and EDGE HD have different backfocus though...

Yes very different.

IIRC you cant use an external focuser on HD's as the corrector is built into the back of the scope?

[cfpendock]

I use an external Moonlite focuser attached to the back of my Celestron 1100 HD.  Works a treat. 

Chris

[Earl]

I use an external Moonlite focuser attached to the back of my Celestron 1100 HD.  Works a treat. 

Chris

I think the C9.25 is a touch different and as yet does not have a reducer either?

[perfrej]

There is the Optec reducer for the 925 EdgeHD. Using a focuser behind the corrector lens is not really a supported configuration as you then change the distance between the corrector and the CCD plane. If you set the focuser to exactly match the correct distance and then focus usingthe main focusing system (primary mirror), you can probably get by reasonably well but may lose some star crispness around the edges.

/per