Scott, Great image! Gotta love the beautifully corrected field of view given by the old 300mm F/2.8L.. Still haven't used mine for astro imaging.. Cant bring myself to expose it to the elements like that just yet!
It looks very clean and detailed for such short exposure... I recently did 18x1200sec subs in 7nm Ha with my refractor/CCD and the image didn't come out quite that noise free.. Mind you, I was operating at F/6, where as you're at 2.8... you'll suck down the data faster than I did...
Top work.. Exactly what I've come to expect from you..