I use an SCT with an OAG and a piggybacked ED80. When I’m imaging with the ED80, I still need to focus the SCT (ideally through the guide camera although in my current setup there will still be an imaging camera on the SCT) to be able to guide properly. Someone asked about this last April and received an “I don’t think there’s a way” response from a mod, though nothing definitive. At any rate, since I don’t think there’s a way either, there really needs to be a way, so I’m adding this to the request list!
While there isn’t a way to both guide through your guide camera and focus the SCT with it at the same time, since you have an imaging camera on the SCT why don’t you use two instances of SGP:
Take “dummy” images with the SCT, controlling focus on the SCT with the imaging camera, guiding with the guide camera, controlling mount moves etc.
Take your main images with the ED80, but as a slave instance of SGP, controlling focus on the ED80.
You will lose some images on the ED80 during a meridian flip, or during dithers if you dither the SCT.
Why don’t you want to use both scopes, both imaging cameras at the same time and double your imaging time?
The reason to image through the piggyback is the difference in scale. There’s not much reason to be doing a wide field on the objects I can image through the 11" SCT, and vice versa on the ED80.
I’ve already been using the dual instance approach to test things, but it’s pretty clunky in terms of operation and flexibility. Since you’ve added the “load last” feature (great feature, btw) that provides an annoying interaction between the two as to which one was “last.” The bigger issue is really just accessibility and screen real estate. SGP is already difficult in that regard. Now it’s just doubled! =)
Yes that can be an issue. The only way this works for me is to use Windows virtual desktops and have one desktop for one instance of SGP. Otherwise it gets very confusing (still does with two desktops but it’s better).