After really enjoying Ricks recent image of NGC 7793 and then really enjoying the ensuing thread and reprocesses even more (thanks guys )...I decided to go back and look at my effort form last year...whiiiich I decided was a bit lack luster and lacking a bit....
So, here is a reprocessed version that hopefully breaths some life into the image...yes there is some colour vibrancy buuut I have tried to keep it relatively natural looking as usual no darks an no flats and I did almost no noise reduction but (buckling under the pressure ) I used gama correction and offset to tame the noise very slightly.
See, those who haven't enjoyed the Starlightxpress advantage think what I do is crazy but as Ray has shown beautifully in the imaging equipment section of IIS the Sony chip and the H694 are perfectly capbable of being used as such ie such low noise and even sensitivity across the chip that unless calibration is done perfectly with many many darks, flats and flat darks etc adding darks and flats is more likely to add noise to the final image than improve it and even when done perfectly the improvement is very small and hardly noticable. The residule noise in my images pointed out by Mr Haese is not from the lack of darks, flats or flat darks but from my agressive stretching and the lack of distaste I have for some noise in my images...so there you go Since my AG12 illuminated field is much bigger than my chip and I have no dust bunnies, flats are much less necessary too and I rarely use them either.
Very nice shot Mike. Shows a lot of intricate detail near the core, which is often missing from a lot of shots. Nice colour in the faint fuzzies too.
Quote:
Originally Posted by dvj
Hi Mike, Lovely image. But why no darks or flats?
I can understand the no darks (just) as some chips have very little dark current, but not the no flats. No optical system is so perfect that it won't have dust on the filters, vignetting and PRNU. Flats will fix these.
Very nice shot Mike. Shows a lot of intricate detail near the core, which is often missing from a lot of shots. Nice colour in the faint fuzzies too.
Thnaks Geoff
Quote:
I can understand the no darks (just) as some chips have very little dark current, but not the no flats. No optical system is so perfect that it won't have dust on the filters, vignetting and PRNU. Flats will fix these.
Maybe in theory sure but hey I'm happy with my results, what can I say
Look you are quite right Geoff, while I have no sign of any dust bunnies or classic vignetting in my optical train, when imaging a galaxy field or small object with lots of dark sky in the frame some slight sensitivity variations do show up but they are normally easily handled by post processing or cropping out. In my recent NGC 247 image for example though I did use flats in order to make sure I surfaced the faint bridge in that galaxy chain top right as it lay in the exact area I see the slight sensitivity variation. I accepted the extra noise in the rest of the frame introduced by the flats and it is not really noticable in this case
Very nice Mike and yes I think this is an improvement over the original. The colours are great and the overall galaxy looks very natural yet detailed. Great work
That's a nice image Mike. I agree the H694 is very clean and you have to be careful about callibration as if not done with lots of darks making the master and the flats having lots of subs I have seen myself how it can actually introduce noise as long as your filters and CCD window are clean.
Very nice Mike and yes I think this is an improvement over the original. The colours are great and the overall galaxy looks very natural yet detailed. Great work
Thanks Rolf, I'm happier with it for sure, thanks to Ricki
Quote:
Originally Posted by gregbradley
That's a nice image Mike. I agree the H694 is very clean and you have to be careful about callibration as if not done with lots of darks making the master and the flats having lots of subs I have seen myself how it can actually introduce noise as long as your filters and CCD window are clean.
Depends also a bit on the scope used.
Greg.
Thanks Greg, I'm not crazy...truly
Quote:
Originally Posted by atalas
Splendid galaxy work Mike!
Cheers Louie
Quote:
Originally Posted by Shiraz
excellent high resolution image Mike - the repro has a very convincing delicacy and natural appearance
)...I decided to go back and look at my effort form last year...whiiiich I decided was a bit lack luster and lacking a bit....
buuut I have tried to keep it relatively natural looking 
as usual no darks an no flats and I did almost no noise reduction but (buckling under the pressure 
) I used gama correction and offset to tame the noise very slightly.
