I was out again last night with my 135mm lens but without a dew heater so I got better resolution on M31 but not as sharp as it could be. This is a combination of 8 not-too-smeary shots at with the canon t3i at 135mm f/5.6 75 seconds ISO 1600. I stacked and stretched it with pixinsight following Alan Hall’s book then decoloured and dimmed it with the windows photo tool.
The image below is 8 shots at ISO 3200, 37 seconds, 135mm. I did this hoping the lens would get less smeary between wipes. I haven’t decoloured it and the crop is a bit different but, if anything the longer subs are better.
Astrophotography Newbie 