|
Well I must say Lumicon tech support are very good at getting back to you with substantive advice!
* * * *
Sorry for the inconvenience. The following are ideas, starting with the easiest to check.
The first thing to check is to be sure that the prism is mounted correctly. See attachment. The “flat” side should be facing the “upstream” telescope side. The 45º slope of the prism should be facing “downstream” toward the camera. This is most likely correct but not impossible to be wrong. You can see how easy it would be to switch. Just remove two screws and turn the assembly 180º then reinstall it.
Your camera target is one thing but you know the off axis guider is made to not guide off the target object but guide off a nearby star in the same field. The 360º rotation is to help you find a bright enough guide star in the nearby field of your target.
Focusing the DSI: I am not sure but I suspect the focus distance for the DSI is close to what is needed for an eyepiece. So this would mean you need the diagonal (or an extension tube) to focus the DSI. This is different than shown in the picture you sent. I heard that the depth of focus is almost nil for a DSI so it would be harder to find.
Most troubling and puzzling is you say moving the telescope did not change the doughnut. This points to something very wrong. You should be able to move the telescope and get a full doughnut in the off axis tube. OR is it not a full doughnut because it is off axis? And it will always be less than a symmetric doughnut no matter where you point it? The off axis image will be good once it comes into correct focus? Is it a non symmetrical doughnut because it is picking up some coma? Is it too far off axis? Some daytime test might be necessary just to figure out where focus of the off axis is.
The first thing to check is the prism direction.
You are the first person to tell us about using the OAG with an electric focuser and a CCD camera with a OAG.
Let me know what you find out.
* * * *
Well I just tried daytime focusing on a tree about 150 metres away - could see the leaves and bugs on them easily! I managed to get the OAG guider to focus in a 22mm eye piece by moving it outside the diagonal - so I guess I need just a tad more extension on the DSI (which I can probably to short term with a barolw I have for the DSI).
Next problem is to try and find a 3" extender tube with diammeter 1.25" (versus teh common 2" ones).
Merlin - when you say move the Guide Port on the OAG so its in the RA direction - what orientation is that - 12 noon, 3 o'clock, 6 o'clock or 9 o'clock?
Many thanks,
Matthew
|