Celestron OAG question

[The_bluester (Paul)]

Is anyone on IIS using the Celestron OAG, specifically on a C925 with the Celestron reducer/corrector?

Having finally lashed out and bought a guide cam in the continuing slow build up of parts for AP. I am seriously looking at setting it up on an OAG as image shift is noticeable when focusing these scopes. I have to assume that the mirror is likely to move somewhat under gravity as well as the scope moves through the night and through an OAG at least the impact would be reduced by the guider, where a guidescope will sit there fat dumb and happy.

Just wondering about the reducer as the Celestron manual for the OAG does not mention it. I assume that the reducer goes in front of the OAG and then some fiddling with spacers may be required to get the sensor (DSLR) at the right distance from the reducer?

[Merlin66 (Ken)]

I use successfully an "on axis guider" - reflective slit plate for spectroscopy and PHD2 can easily hold a target star on a 19 micron slit gap as long as required. This is a C11 on a NEQ6pro mount.

I find that the mirror slop/ flop on the Celestron much much better than the Meade SCT's I had. The trick is to regularly move the primary mirror through the full focus travel (30 turns or so) to re-spread the grease on the baffle tube.

[The_bluester (Paul)]

If I had the money I would love an Innovations Foresight ONAG, but that is more than a little out of the budget! The ability to guide and live focus is pretty appealing.

[brisen (Brian)]

Hi Paul

I have the OAG for a C11 but haven't used it with the reducer. On the refractor I am using for imaging at the moment the OAG is in between the flattner and the CCD. As you say, its then a matter of getting the spacings correct to achieve focus.

Brian

[The_bluester (Paul)]

Reckon I will have to save up and get one then.