Very nice detail Greg especially in the faint nebulosity.
Here is an animated gif of your upsized image with the same area from my large Saggitarius Mosaic. 7MB.
http://d1355990.i49.quadrahosting.co...010_08/gb1.gif
Click anywhere on the image to see it full size.
We are comparing a 300mm FL effective 84mm diameter at f/3.5 using a DSLR to 1260mm FL 180mm diameter APO at f/7 using an astro CCD.
You can see why the Canon 300mm F2.8L is held in such high regard by me and many others.
Bert