I'm the happy new owner of an AM5N + C9.25 XLT combo. The main purpose of the rig is to serve as a compact(ish) alternative to my 10" dob for visual astronomy. The C9.25 is of course also a wonderful instrument for planetary AP, which I have just gotten started on last night (first capture ever, yay me !). For DSO AP, while it's not impossible to make it work, as many have pointed out to me it'll certainly be one hell of a challenge for a complete beginner. So I took the advice of my betters and am now in the market for a small APO to fill that final niche.
On the other hand, my only disappointment with the rig so far is the goto accuracy. The tracking is great, but the pointing is way off even after multi star alignment. My first night with it was horrendous on that point, though on my second night I've managed to improve it quite a bit with a few simple tricks (more stable ground, syncing to stars around my final target, etc.), though it's still far from perfect and works best close to synced objects. While perfect gotos might be a bit of a luxury, I feel like they could really make an observing session so much more carefree. One drastic solution that's been suggested to me is stick a guidescope on top and have it platesolve for me, and there of course I can expect absolute perfection (up to questions of flexure, but though that may be an important issue for AP, I'm assuming it can't get so bad as to drastically impact casual visual observation). At first, I really wanted to avoid this route because I could already imagine the tangle of extra cables and hardware and installation woes that this would entail. While that's the norm for AP, it would kinda suck the fun out of a visual session where I just want to point at things and look at them.
So why am I bringing up both those problems at the same time in the refractor forum ? Because I realized that combining the ASI2600MC Air with a small APO, I might actually be able to hit 2 birds with one stone. I could mount the small APO on top of the C9.25 as a guidescope with the 2600Air, and the cabling would be kept to a bare minimum : external DC power to the 2600Air, DC output from the 2600Air to the AM5N (ZWO recommends that order rather than the opposite), then a usb C connection from the 2600Air to the AM5N. That's it : 3 cables, 2 of which rotate end to end with the scope so no snagging, and power supply snagging or curling is a potential issue not matter what. And I'd have a perfect plate solving goto system attached to a wonderful visual instrument that I could completely control from my phone. And then of course, I could just use the APO alone with the 2600Air to start my DSO AP journey, with the added benefit that the 2600Air being an all in one package would make an easier introduction to DSO AP.
So is this an utterly nonsensical idea or a very efficient solution to both my needs ? If the former, what's wrong with my reasoning ? If the latter, I'm very open to scope recommendations !
The APO in question needs to illuminate a fairly large field, not merely to fully illuminate the APS-C sensor of the 2600Air, but to make sure the integrated guide cam is well illuminated. I believe the recommendation is to have a scope that can illuminate a full frame. For guiding, I'm not sure how much it matters if the outer edges of the frame are aberrated as long as they're well illuminated. On the other hand, I'd like to keep it fairly small and lightweight to let me still utilize my rig without counterweights when it serves as a guide scope on top of the C9.25. Is there a 2600Air compatible APO that weighs under 2 kgs ? The lighter the better. Given that I'm looking for something small I don't expect the price to go too far above 1k, but if something perfectly suits my needs and it's more expensive then so be it.
And of course, if anyone is familiar with the 2600Air and in particular the user experience end of things, I'd love to hear if you think this can indeed lead to hassle free observation sessions, after a bit of setup perhaps. Simply put, how user friendly is the interface if I want to use plate solving to perfectly guide to a target ? I'd also like to avoid throwing in an autofocuser. Is it easy enough to manually focus my guidescope using the image preview ? Feel free to add anything about the 2600Air I may be missing.
Clear skies
Edited by TicoWiko, 20 March 2025 - 08:02 AM.