Thanks for all the kind comments folks. My main aim is to make 'natural' looking wide fields for my enjoyment and yours.
The 'noise' you see is faint stars not quite resolved either just above or mixed in with the real noise and sky glow and light pollution.
Since there are two green pixels for every red and blue in a DSLR sensor small dim unresolved stars first manifest as green 'noise'.
Here is an animated gif of part of my image with an image of Greg Bradley's taken with his TEC180FL.
From here
http://www.iceinspace.com.au/forum/s...&highlight=tuc
I upsized his image to get closer to the original quality which is most probably far better than this.
Animated Gif 2.5MB
http://d1355990.i49.quadrahosting.co...010_06/47t.gif
You can see that the very small dim stars that are well resolved with Gregs superb TEC180FL 1260mm FL F7 optic fairly well match the 'noise' in my image. The Canon 300mm F2.8L has a measured FL of 290mm.
I have pushed my system to get the best data for widefields. This of course is to maximise resolution and signal to noise.
Knowing what is faint signal and what is real noise helps to improve my methods. The trick always is to record the real signal and minimise the noise.
I am sure that when I collect far more data with the SMC at the zenith even these faint stars will start to 'show' above the real noise and light pollution. Gradients will also be far less as gradients are just sky glow and light pollution that varies in intensity over the image.
Bert