I've been using an 80mm APO scope on a CEM25p with fairly good results. I've also used the 80mm on my DIY EqMod mount. Last night, I decided to try my 8" SCT on the DIY EqMod mount. Focus was spot on but I could not get the alignment module to solve. The image would upload, I'd get the message waiting for astrometry.net, and then it would sit there until timing out. Lather, rinse, repeat.
Perhaps an idea. I had the same problem with a meade Sc 8" and an atik 314L+ (So with a small field).
When I change the back focus with the camera (because I use a fliterwheel or not, ...), to focus it changes the position of the primary miror. So the focal change.
And with a 6.3 reductor, the focal is not necessary 1260.
Now, I have resolved the field of an image with astrometry.net, I noticed the focale, and I reported it in Kstars/Ekos (For me, it is 1170, not 1260). And I try to have always the same backfocus.
And I try not to touch the position of the primary miror to focus.
I am a but embarrassed, but in a good way because I learned some stuff.
Following the suggestion, I upoaded an image to astrometry.net and it solved. I had to download some more index files, but even then I couldn't get a solution. The embarrassment is that when I went back through my profile, I saw that I had created the 8" SCT entry but had NOT selected it. So, Ekos was trying to solve the image from the SCT as if it were from my 80mm. D'OH!
After that, I was able to solve around Polaris, but the solver said I'd need another index file for plate solving in general, and it was 8.xGB and I decided to get that today (which I have). So, I *should* be ready for tonight!