Re: [APML] ESO Tarantula CCD image

["John Boudreau" <jeboud@attbi.com>]

>
> Did you know you can do RRGB combines with a single film shot? ever notice
> how E-200 has excellent signal in the red layer but horrible in the blue?
> try copying the red channel and pasting it as luminosity over the color
data
> of a Nebula shot- it works wonders.
>
>
> Sean Walker
>


This is actually what I've done on some of my Provia 100F film-based
planetary nebula shots. Sean has worked with some of my image files himself
and helped me out in this type of processing. Since the red layer has the
best signal, much more aggressive processing could be done on it to bring
out detail for use as a luminescence layer. The image where I took this to
the furthest extreme so far is a shot of the Cat's Eye, which approches in
resolution a CCD image of the same taken by Sean and myself last year.
Actually the blue channel was taken from a 15 minute exposure in this
example, due to excessive noise in that of the primary 10 minute exposure.

Film version: http://home.attbi.com/~jeboud/ngc6543.htm

CCD version: http://home.attbi.com/~jeboud/ccd_ngc6543.htm


Of course, the film and CCD record the colors differently. The CCD version
has the more accurate color as it records OIII emission well, where the film
is almost blind there.


John Boudreau
jeboud@attbi.com
http://home.attbi.com/~jeboud/astro.htm


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