Quote:
Originally Posted by strongmanmike
And that's about it Ray...being able to do without flats is simply a function of ones system ie a fully illuminated field, a chip with low NU, clean correctly sized filters, wide image train openings to avoid vignetting, a dark sky and.. voila 
I am able to surface extremely faint features without flats and I have not seen a single dust donnut, not one, even with extreme stretching 
Mike |
I have seen one dust bunny in the year I have used my 694 - not an issue with a fast scope and the camera window a fair way from the CCD. However, I have recently started using the dark/flat calibration routines in Pixinsight and am getting a useful increase in SNR from doing so - getting rid of some FPN can sometimes help.
Quote:
Originally Posted by gregbradley
Apart from dust bunnies I found flats on some faint galaxies seemed to make some images more noisy I had taken with 694/CDK17.
But I did not have 16 or so flats median combined either so perhaps that is worth pursuing before its a fact.
Dust bunnies require either a clean or flats. Such a small chip is a long way from being vignetted on that setup. Other scopes may vary. My 16803 totally needs flats on the same scope.
Greg.
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Hi Greg - sorry that this overlaps with your previous thread to some extent. I also find that the 694 needs very good quality flats or else you can lose SNR by introducing noise via the flats - darned quiet cameras these are.
Quote:
Originally Posted by LightningNZ
I realise, and I didn't mean to derail your thread - sorry if I have done.
I just use my PC's LCD screen for taking flats. With an APS-c sized chip on the AT65-EDQ there's no vignetting at all. I do get occasion dust marks on my images - I'm generally not too fussy about keeping the 2" filters spotless.
Cheers,
Cam
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Thanks for the info Cam. Must try a laptop screen. I made up a foam box and that works OK, but it is a bit clumsy to use.
Threads tend to go where they will and you have in no way derailed this one - but even if you had, no problem
regards Ray