This is a stack of ten 4 min exposures at an ISO of 1600. They were taken with the Canon 5DH and the 150mm F4.5 SkyWatcher achromat after the Moon set. The Canon was in the fridge at -4C.
Large Image 1.1MB
http://members.optusnet.com.au/~cheekyfish/ic4628.jpg
The red channel was a bit out of focus compared to the green and blue but not bad for an achro. There is no violet ring as the Hutech nebula filter does not pass any shorter wavelengths than Hbeta that cause this.
I used ImagesPlus to slightly reduce the red channel with the star and halo reduction option. This got rid of the slight red ring around the brighter stars.
Bert