M33 is a classic northern hemisphere DSO. However, I thought I'd take a challenge and capture it low on the horizon from the south (it never rose above 22 degrees altitude). There was also substantial light pollution and a hazy atmosphere to peer through, and it was imaged through an achromat (at f/4), which meant that it was impossible to gather focused Luminance frames (so the Lum was synthetic, based on a weighted blend of the R, G and B channels and Ha data).
The overall result is not great (the R and B channels bloat badly with the achromat - this is really only good as a narrowband astrograph), but at least I can say I tried!
Ha = 16 x 900 sec
R = 48 x 100 sec
G = 44 x 114 sec
B = 47 x 92 sec
(RGB sub-length determined for optimal colour balance). Ha-R was used for the R chrominance channel. Post-processed using Startools.
For now, I think I'll keep the achromat for exclusively NB imaging!
Full capture details and higher rez images here:
http://www.astrobin.com/126583/B/