Here is a shoot off of sorts.
First image was taken with a 12 inch Ritchey Cretien F9 and SBIG STL11000M 11 MP monochrome cooled CCD camera. Full Autoguiding on Paramount mount. It is a LRGB image 30 secs lum 1x1 bin and 30 secs rgb 2x2 bin, processed with calibration images in Iris.
2nd was with a 22 year old 10 inch f5.6 newtonian and "Sampson" GEM mount with Shyncronous motored RA drive and manually operated drive corrector, with 2x barlow giving f11.2 Hutech modded Canon 350D with uv/ir and Baader UHC-S filters. 2x Drizzle upsampled during processing. Off axis guided with Q guider camera showing guidestar on laptop where I guide by placing an artifical reticle over the star.
The 2nd image took considerably longer and could not be done "hands free" but does show that ancient equipment of what many would call the RA drive in particular low quality and a vastly inexpensive camera can produce images that are reasonably impressive, and unheard of for the time the scope was built. I should mention my scope has a full thickness Pyrex Sutching mirror, I think only Ion Milling could make a better one than that
To be fair I am not sure how good the seeing was when I took the GRAS image on the RC scope, and it is an excellent image in its own right. I could not affort to do an imaging run on it as long as I did on my system last night. Anyway the GRAS image is not grainy, showing Ive got plenty of signal anyway.
The 3rd image is of the Eta carina Nebula, again with the 2x barlow giving F11.2, duration 92 seconds ISO 160 with uv/ir and UHCS filter, hurriedly taken before more cloud came over. It shows that particularily with H alpha emission, the modded DSLR with its 4x more Ha sensitivity then a non modded one can hold its own.
If a Canon Cmos sensor like the one in the soon to be released 450D could be obtained without the colour bayer array and antialiasing filter, with a simple single stage peltier, and say 10 or 20% longer imaging times to account for a slightly lower QE, I believe it could take images better then anything dedicated Astro CCD's could muster. They might have the edge with fancy back illuminated chips (horrendiously expensive to make due to high failure rates during manufacture). But compare a raw frame from a ASTRO CCD camera with one from a Canon DSLR. The CCD might have column defects and a scattering of dead pixels. These are of course mapped out during processing. But the CMOS Canon sensor has (or should have) none to start with. They are designed to produce the best normal photographic images possible without defect. They dont suffer from dust as much as the cover plate is further away from the sensor. Also remember to consider the most sensitive CCDs do not have Anti Blooming Gate (ABC) and bright stars will bleed down the colums. having ABC is well worth the sacrifice of QE!
Sadly as yet there are no monochrome CMOS DSLR sensors from canon. So I propose in the interim a most fair shoot off. Compare the DSLRs to a COLOUR Astro CCD camera. Pit a dedicated astro CCD one shot colour against a cooled DSLR from
central DS
This would be my ultimate imaging device. A monochrome version of
this with single stage peltier cooling, no IR cut filter , no Bayer filter array or antialiasing filters. 21.1 megapixels.
Thought id mention many moons ago I got to have a play with a then top of the line ST7 on my gear for one night
http://cust.idl.net.au/josiah/SBIG.htm
The ST7 was a nice little unit, easy to use and did not bloom, if only they were not so costly.