Hi Rod,
That's quite a recognizable Rosette with some decent detail. It's a bit dark which is probably because you didn't have the SNR to stretch it too far. IMO, the thing you need to do first is start getting some longer subs and reducing the effect of read noise. If you're interested there are ways to determine the sub length needed to take sky limited subs for your set up and conditions - let me know and I'll pontificate further
Cheers,
Rick.
I would welcome additional thoughts regarding exposure length. I have struggled a bit with that issue.
Since I started using the Paramount MX+ last Summer, I had been using exposures of 300s to 360s. However, a friend in our local astronomical society had his own thoughts about the exposures I should be attempting and had done some calculations for me. Due to the very low focal ratio of my system (
f=2.22), he had arrived at the conclusion that I should be using very short exposures, e.g., less than a minute for RGB subframes, a couple 10s of seconds for Luminance, and perhaps a minute or two for NB subframes.
I have tried LRGB exposures of that magnitude since on both the Rosette Nebula (NGC2237) and the Jellyfish Nebula (IC443), both relatively faint objects. I didn't have much luck when I tried processing because there just wasn't very much data. I used 60s/subframe for imaging the Pleiades (M45) with pretty good results. This attempt on the Rosette represents a move toward longer exposures (240s) again.
I am imaging unguided with the Paramount MX+ and it's "TPoint Supermodel" and "ProTrack" tools. I have experimented with exposures up to 10 minutes with good results and have settled on 6 or 7 minutes as my upper limit for now.
From your comments, I conclude that longer exposures and a larger number of subframes, e.g., for the Rosette perhaps 300s or 360s and 50 subframes for each color (4 to 5 hours per filter as opposed to the 2.3 hours I have for this Rosette), will improve my result.