I've posted these pictures multiple times already, but since no one else seems to have drawings to show what's possible with a 6" refractor, I'll post them again. The two first are done at the eyepiece of a 6" f/8 achromat, while the bottom one is done with my APM 152ED, all from a Bortle 3 zone.
M51, observed March 12th, 2012, with my 150mm f/8 Sky-Watcher achro. Baader Maxbright bino, magnifications 30x, 60x, 80x and 120x. SQM 21.4. Somewhat hazy. NELM about 6.
NGC 891 observed December 27th, 2011, with my 150mm f/8 Sky-Watcher achromat. Baader Maxbright bino w/ 25mm kellners, 48x and 10mm kellners, 120x. The dust band was not seen, but the bulge of the galaxy was slightly brighter on both sides of the band. Seeing was OK, but transparency was mediocre, with stars slightly soft from haze. The view is mirrored, to show how it appeared using a diagonal. The northern end of the galaxy was fainter than the southern end, but this was hard to show in the sketch. It also appeared a little shorter, for some reason.
M27, observed July 27th-28th (midnight), 2020, APM 152/1200 ED, 9mm ES100 for most details, 17mm ES92 for the faint extensions. Clear, but white nights not quite over. Milky Way easily visible, NELM ~5.5 - 6.
Edited by Astrojensen, 17 April 2021 - 01:54 PM.