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Modded DSLR or Cooled CCD (Colour)?


Ouroboros

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Regarding DSS do you know whether the software is doing this automatically or does a setting have to be clicked somewhere?

In DSS this is called "Entropy based dark frame subtraction".  It is an option that needs to be switched on.

It gets a brief mention within a section with the same name here:

http://deepskystacker.free.fr/english/technical.htm

Mark

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In DSS this is called "Entropy based dark frame subtraction".  It is an option that needs to be switched on.

It gets a brief mention within a section with the same name here:

http://deepskystacker.free.fr/english/technical.htm

Mark

Thanks. That's very interesting. I hadn't picked up on that one in DSS. I might run some of my data again to see if makes any qualitative difference.
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No more stressing over taking darks  :)

Hope that makes sense.

Mark

Thanks for explaining, Mark. It would be good to not stress over darks. I have PixInsight so will look deeper. Cheers.

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I would probably buy a modded DSLR if I went down the DSLR route.

However, regarding taking dark frames I really resent the time spent during an evening imaging.

I am hoping that a cooled CCD allows for darks not to be taken at all or to be taken during the day at the same temperature.

Have you ever opened you CR2 RAW files in photoshop camera raw plugin... It does an excellent job on only removing the noise and you can batch convert all of your CR2 files to tiff with the noise removed. You'll find that you never have to do dark frames again.

As far as cooled CCD is concerned, you will only get marginal improvement over what you're getting with your DSLR, certainly not as much improvement as the difference in price.... Cooled CCDs really shine when imaging through filters, particularly NB.

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As far as cooled CCD is concerned, you will only get marginal improvement over what you're getting with your DSLR, certainly not as much improvement as the difference in price.... Cooled CCDs really shine when imaging through filters, particularly NB.

I cannot even begin to agree with this. I'm fully devoted to CCD and use narrowband only to enhance natural colour images so I do no dedicated NB imaging whatever. At the moment I'm working on dusty targets and the power of luminance, which captures (theoretically) three times the light of OSC but really captures about four times, makes all the difference. And then there's the question of shooting twice as much green as red and blue, which you do with a DSLR. Why would you do that? We know why you'd do it by day, but at night? And then there's well depth, which is very important when it comes to targets with high dynamic range. Star colour, in particular, needs good well depth. And then there's cooling. If you are working at slower F ratios, particularly from a dark site, the CCD ability to do 15, 30 or 60 minute subs is wonderful. And your darks are set point cooled.

DSLRs do pretty well in incredibly fast optics and that's about it, in my view. CCD is another world.

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

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Olly - I'm slightly confused by your last post. I assume MarsG76 was referring to cooled OSC CCDs provide only marginal improvement over DSLRs. Is it that you're disagreeing with?

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Olly - I'm slightly confused by your last post. I assume MarsG76 was referring to cooled OSC CCDs provide only marginal improvement over DSLRs. Is it that you're disagreeing with?

Ah yes, I hadn't considered that the post referred to OSC. If that's so, my mistake and my apologies.  I think most CCD OSCs will still beat most DSLRs quite handsomely but the advantages of mono are the really important ones.

Edit; to give examples from the two images on which we're working here at the minute: one is a widefield Ha region. We're doing just RGB and Ha since nearly all the interest is in Ha. The other is a dusty VDB object with a tantalizing bit of faint Ha thrown in. By far the best way to get the dust above the noise floor is in Luminance and the Ha obviously thrives on mono. Both objects have opportunities for 0III as well.

Olly

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