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Hi Jennifer first of very nice image of ETA Carinae, really good for unguided. Do you have a picture of your image train you can post so we can take a look and help with it?
I have just gone through the issues of attemtping to get prime focus with my 9.25 SCT with a 6.3 reducer and the same 450d camera you have. The further the distance your camera is away from the scope and reducer the less chance you have of reaching prime focus. This is especially true of SCT as when you have a reducer on the back end and 450d camera you are almost at the back end stops with no place to go to get the extra crisp focus. You have to remember there are two different types of main SCT scopes but three type of reducers. They each have different lens arrangements giving their own individual focal lenghts.
Meade make their scopes, a reducer for their scopes and a T adapter for their reducer. These are all matched so you can place a camera on the back and reach prime foucs. Celestron also do the same thing, they are designed to be in this order by their perspective manufacturers to be able to work as they are supposed to.
I had a Celestron scope, a Meade reducer and a Celestron T adapter and could not reach prime foucs at all the Celestron T mount adaptor was just too long when matched with the focal length of the Meade reducer, I managed to pick up shorter version from Bintel which allowed the camera to be closer and it moved the primary mirror inwards away from the back stops to allow more focus.
So now we come to your problem which is different again, a Meade scope, an Antares reducer, an Orion of axis guider, a T adapter then your camera. (This is why an image would be great)
I would think this is a similar problem you may have if it is focus you can not achieve.
But if you can move the primary mirror either way still it may not be focus but collimation that is your problem. With my system I have to collimate each time I swap from f10 to f6.3 for a nice crisp image.
Hope this helps somewhat.
I have edited the post to add these snippets I just located for a visual note of how much different each of the reducers are and how much the spacing changes, as you can see the Celestron is most forgiving allowing up to 105mm of spacing the Antares is the nastiest only allowing 79mm.
Celestron 0.63
Focal length 284mm
Correct spacing 105mm
Meade 0.63
Focal length 260mm
Correct spacing 87mm
Antares 0.63
Focal length 220
Correct spacing then 79mm
Carl
Last edited by carlstronomy; 03-03-2013 at 12:28 AM.
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