Because of their limited aperture, refractors are not ideal for imaging or visual observation of galaxies. That said, if you own a refractor as your primary or only scope one must adapt.
Most galaxies are relatively small targets, so you will likely want to crop quite a bit. A camera with small pixels can help eek out as much resolution as your skies and diffraction will allow (at the cost of more perceived noise, so you’ll want lots of integration time; no free lunch).
With the FSQ, something like an ASI183 would be ideal for smaller targets. You’ll still have a reasonable number of pixels after you crop for your subject, and you’ll have gotten all the resolution that you can. That combo (without the extender) will yield just under one arc second per pixel. That should be just about perfect. The diffraction limit of your scope is just over one arc second. Couple that with good to average seeing and good guiding and you should be able to get 2.5” FWHM images which is enough resolution for most of the showcase galaxies.
Edited by Jared, 13 May 2021 - 10:33 AM.