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Sorry
Tony and all,
I get
it now. You have to keep going back and adjusting levels and curves for
several iterations. Is that right? This is really pretty cool.
Jeff
Ball
Hello Tony,
Well, count me in the crowd who doesn't know what
they are doing. I have a stack of M51 images. 9 images x 10
minutes unfiltered through ST10 and AP130EDT. They look fine in 8 bit
.tif mode in PS, but, like you discussed, the nucleus is burned out. I
have put into place the .fit plugin and I can open images in PS. I have
opened the reduced/combined images (performed in CCD soft) in PS. I have
tried compressing with levels and then use curves and I still can't bring out
the detail without burning the nucleus. Any tips you can give or the
order of operation would be greatly appreciated.
Jeff
Ball
Jeff,
It is my personal conviction...
and I say this because I am still very much a CCD "newbie"... that if most
CCD images are exposed correctly (not hitting the saturation point on
the nucleus) the nucleus should never be burned up. The reason that you see
so many burned up is, I think, because the practitioner is using canned or
"automatic" processing that is setting the end points without regard to the
detail in the nucleus. Being a FILM person, I could never let that happen! :
- ) The 16 bit linear data from the CCD is amazing... but when you
look at it without compressing it, all you see is a few dim stars and black.
By using curves and levels in PS, one can compress the data without clipping
the end points... little by little the image appears before your eyes... and
the "natural" stop point to this process will be the noise that begins to
show up as you compress... it forms a natural boundary. So if you can
suppress the noise, you can "go where no man has gone before..." Beam me up,
Scottie!
Tony
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