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Re: [APML] NGC 2903 OT

Tony - wow! I will save this note and as my skill levels increase, I
will try to imitate this. Thanks!

Stuart
http://www3.sympatico.ca/stuart.j.heggie/Stuart.J.Heggie/
Flesherton, Ontario, Canada

----- Original Message -----
From: "Tony Hallas" <tonyhallas@foothill.net>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Monday, March 22, 2004 7:06 PM
Subject: Re: [APML] NGC 2903 OT


> Hi Stuart,
>
>     It's a bit more complicated than that ... you start with a 16 bit
image,
> in this case a Tiff file ... it is the result of all the reduction
that you
> did on the CCD data prior to "opening" the image. Unlike a film image,
a
> good CCD can grab the 16 bit data right out of the sky. What this does
is
> give you a much greater range of densities than is possible with film,
all
> in one image.
>
>      So using curves in PS, it is possible to open this image to
different
> levels ... you can open the image to the very faintest levels ... this
will
> show all the faint fuzzies and also all the noise in your image. You
can go
> back to the original file and this time open it to the threshold of
noise
> showing up. You can open the original file so that the core detail in
the
> galaxy is maximized. If you save all these images you now have a
palette to
> draw from and construct an image that has the best of all features. I
can't
> tell you exactly how I combine the noise-free background with the
faint
> fuzzy one and keep most of the fuzzy detail, but I can tell you that
it
> utilizes layers and a form of masking. The nucleus detail can be "cut
and
> pasted" into the image like working with M-42.
>
>       Does this relate to anything with film? It might if you blur one
image
> for "smoothness" and combine it selectively through a mask with the
"detail"
> layer ...
>
>      Clear skies,
>
>          Tony
>
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>

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