[Gama]

Firstly, your comment about median filter insertion for the D200 isnt true. It is a Raw output. You are refering to the D70, D50 etc. You can disable it with the D200.
Secondly, if you look at the Histograms for both you will see that the 20D has substantial more signal in noise that fills the entire grid, where as the D200 has very little signal level and only occupies a tiny portion of the Histogram grid. Thus i said that i did not do any stretching what so ever, so the Canon due to its higher noise signal falls over the set points and thus shows up more red. If i adjust the set point for the Histogram levels then im altering the cameras initial signal levels it determines and saves. This is what you did, you modified the histogram to suite your noise levels. It would be good to see the actual histogram for such a long exposure..
Histograms contain your data and noise information, so the less Noise signal you have to start with the better your signal will be and also handle enhancement processing.
Check the images i posted for the 2.
I did this test because it shows just how much noise is actually effecting a real signal comming in. The less signal (Noise) you have here is obviously desirable.
Your exposure of 1020 secs has built up a large noise level. A proper image shows exposure shifts of the histogram to the right more, where as a less signal, the histogram is shifted to the left.
This backround will obviously not show up on your image because you modified the levels to suit your exposure. If there was a signal with that noise then the signal would also be effected in the same way.
The 20D failed, im sorry you just cant accept that. You always trying to defend Canon with conspirecy theorys and counter reasons to everything i test and display here.
No conspirecy theory, no bias to Nikon, as i said i own and use the 20D for Astrophotography. But call a spade a spade. Nikon have brought out a good camera for us Astrogeeks, all be it with a cruddy CCD filter.
As for the Cmos Vs CCD, i was not comparing the monochrome CCD version. In fact i compared it to the SXV-M25 which has the same chip as the D70. This CCD chip has a much higher QE than the Canon Cmos sensor. Again, no tricks, no smoke and mirrors.
The image of the M83 with the 8" f4 is exactly that, f4. What are you trying to say ?, nothing to do with the camera, cause its f4 to f8, makes no bananas that mines a 14" when his is an f4 astrograph. Now if i placed my f.5 reducer to bring my 14" to f4 as well, then what do you think the outcome will be when i place any camera on....
Terry, take my hand and come over to the DARK SIDE .hehe Darth Gamma

8 out of 10 beer drinkers cant be wrong !.