Thought I would post this with all recent shots of Eta - shot this back in April:
12 X 3min subs at ISO1600 and jpegs ICNR
Takahashi Sky90 with flattener @ 4.5 with Astronomik CLS filter
Canon 400D unmodded
QHY5 guide camera through a Canon 70-300mm zoom lens @ 300mm
Stacked in Nebulousity, with processing in Nebulousity, PS CS3 & Neil Carboni's actions
I know I need to reduce the ISO and shoot in RAW. Histograms are little over the place as well - too much processing probably.
I have been following the posts with ETA including Leon's "Just Compare" with
the modded and unmodded 5D and trying to work out whether to get the 400D modded locally or perhaps buy a new Hutech modded 450D (I'll be in the US in a couple of weeks) or perhaps a QHY8. Or just go unmodded for the moment and learn more on processing, guiding etc.
Do you expect to get much improvement from RAW. I process in images plus and when it converts the RAWs they come out very dark. I was going to try jpegs and see if much is lost... not much judging by this
jpegs limit your limit to push the image being only 8 bit ie 256 variations for each color chanel. you will get away with it to some degree on a bright object but when you do a dim one you will come undone to some degree. 12 bit gives you 4000 plus variations so if you are trying to enhance a faint object you can get more graduations without banding and speckling. thats why the ccd cameras are 16 or more bits .... just gives you more flexibility.
you can always just convert your 12 bit Raw images into Tiffs using Canons proprietary program (although tiffs are 16 bit you really only captured 12) then stack the tiffs in deepsky stacker or another program, thus bypassing the hassle that some programs have with RAW files. Ultimately this will give you a better image as you progress with your imaging.
Thanks Robert. I have taken some RAW's on a few objects but haven't got around to processing and comparing. My next task.
Thanks for the advice Clive. I did take some some recent shots of M16 and M17 - fainter objects - and regret now that I didn't take them in RAW. The fainter detail does look a little blotchy which is hard to remove. So RAW's in future.
Doug, I wonder if the 400D picks up a little more H alpha than the 40D. But I know I'll need a modded camera if I want to do the Horsehead or any H alpha work for that matter. Regards the Hutech modded Canons, with the Canon rebate, the 40D is not much more than the 450D. Have to make up my mind soon. The QHY8 is looking too complicated for me at the moment.
what a great shot. 
