With my 6se and 385mc sensor I do a lot of stuff at 5s or 10s max exposure per frame at a high gain of 450 while dark correcting when livestacking in SharpCap. When using a UHC or other narrowband filter the star bloat from the high gain gets reduced quite a bit. The other night I was livestacking Thor's Helmet, Bode's galaxy, and Leo Quartet as well as a few other objects at ~f/3.3 (combo f/6.3 with cheap 0.5x reducer) and never dropped a frame with up to 45 min total exposures. I've read that the se mounts make a tracking correction every 30 s so short exposures are best to eliminate the star distortions caused by too long of exposures per frame.
Also, not a big deal considering the imaging results people get, but the C8 is pushing the SE mount as far as weight capacity goes and one of the reasons I got a 6se, besides the lower price, was it left more head room for the weight of addons. Total exposures are about 2x longer but you can do a heck of a lot with reducers and a smaller sensor. For your A6300 the f/6.3 is your only real choice for filling the image frame and gaining about a 2.5x faster exposure with overall field flattening. If you don't mind a smaller image and losing imaging capabilities in the outside region of your camera frame from the vignetting you could still use a 0.5x reducer and decrease exposure times even further, but with no designed in field flattening. It's all a tradeoff in that you're just packing a fixed number of photons into a smaller area on the sensor for faster image acquisitions but trading off image resolution in the process. Very few free lunches in astronomy unfortunately. (Those cheap, ~$30, 0.5x reducers are pretty much the same piece of glass used to make the objective lenses in cheap binoculars only mounted in a 1.25" spacer tube . A few people even make DIY 0.5x reducers from old binoculars.)
With my 6se I've done quite a few 45 min total exposures for smaller DSOs when well centered and drifting is under control. The field rotation is part of the deal when using alt/az mounts. I very often can crop that out if the object is only filling up less than about 2/3 of the frame with very little or no drifting.
Maybe you already know this but for the bright stuff, like solar system objects or the Trapezium region in the Orion Nebula, video captures at 60 fps can work quite well for stacking and post processing in free software like Registax 6 and such.
One other thing... If your star distortions are along the altitude axis your scope may be unbalanced and continuously slowly drifting up or down while doing the image captures. This could be happening in your case because you mentioned the drifting is right or left but always also down.
Edited by rnyboy, 12 March 2021 - 11:07 AM.