RE: [APML] March results

["Jeff Ball" <jeffball@zoominternet.net>]

Hey John,
Thanks for the nice words.  The weird stars on the M51 are from a couple of
things.  One is the blooming repair as you mentioned.  The other is from
careless masking of the brighter core I may have copied some dim star data
and copied onto the bright core of some stars.

Like you, I thought the M81 was a weird color.  But to be honest, this is
exactly the color of the PPF.  I am really trying not to radically change
the color of the original data.  I have found I get into trouble when I do
this.  I scanned the PPF with no color management by Nikon.  I would have to
do some radical curve/color balance manipulation to get the blue arms in
M81.  So, I just went with the color balance in the negatives.  The only
time we get the salmon color is when applying RGB to Halpha.  That has to be
done with a lot of steps as described by Rob Gendler.



-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of John C. Mirtle
Sent: Saturday, March 22, 2003 9:27 PM
To: Discussion of Film Astrophotography
Subject: Re: [APML] March results


Excellent Jeff!
    All I got in March for clear nights were either -30 temps or 40 to 60
MPH winds! Nice to see someone got lucky. :-) The ST10 sure changes the
rules! Your M51 is deeper than I have been able to get with a scope twice
the size using tech pan. The brighter stars look a bit strange on the full
rez image though. Is this some kind of artifact from all the stacking, or
from blooming repair? The rosette is equally impressive. The Bok globules
just seem to be "hanging" there.
    M81 looks a little bit too orange to me. I am guessing that when you
inserted the CCD luminance that the colours from the PPF shot went a bit
weird? This happens a lot when inserting tech pan into a colour image. Bobby
M. posted something on this just recently, sorry I can't lay my fingers on
it at the moment. Same result though, the final image goes pink or orange.

Great stuff!

John Mirtle
Calgary, Ab. Canada

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