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I bought a MMOAG ages ago and tried to install it a few years ago. I could not get it to focus so put it aside.
Later on I tried again and still no focus. I read the net wondering what was the problem.
I eventually got it to work.
Firstly the trick with these things is that if they are out of focus even slightly the stars disappear without a trace giving you no clue as to where you are with regard to focus. That's what makes them so hard to focus.
The next point is the distance from the pickoff prism to the guide camera chip has to be the same as the distance to the imaging camera chip.
So work out what the distance is from the pickoff prism to your imaging chip (not the front of the camera - to the surface of the chip).
Now measure where that distance ends up for the guide camera. It now gives you an idea of where the focal point is.
With the MMOAG Don Goldman also sells a negative lens for the guide camera to help achieve focus with some setups. Not sure about the Orion.
The MMOAG came with 2 types of focusers to hold the guide camera.
But the main point here is assuming your pickoff prism is acutally in the stream of light that you won't see much in your guide camera unless you are probably something like 5mm or less from focus.
I hope this helps.
Greg.
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