Re: [APML] OK - here's your blue Veil Nebula

["Mike Cook, AF9Y" <mwcook@concentric.net>]

  Bert,

       The pages preceding the CIE calculator contain an excellent
discussion on the evolution of the CIE Chromaticity chart.  As for
the calculator, it is a bit tricky.  It is designed to accept a direct
copy from an Excel spreadsheet.  Here is an example of an
input with a mix of 1.5 parts OIII and 1 part Hb :

http://www.webcom.com/af9y/calc.jpg

     The output is a point on the color chart which shows the
color for the mix of emissions in the table.



>From:           	"bert katzung" <katzung1@home.com>
>
> Hi Mike:
> Yes, I like this one the best of your various versions. Thanks for posting
> this stuff. I'm currently reading "Measuring Colour" by Hunt, and "Digital
> Color Management" by Giorgianni and Madden, trying to get a handle on these
> concepts. Any other reference sources that you would recommend? That CIE
> calculator you posted is interesting---when they ask for input of the table
> of wavelengths and "emission spectrum," are they asking for the relative
> amplitude of the emission at each wavelength or something else? And if
> amplitude, should it be normalized to the amplitude at some specific
> wavelength? What is the output of the calculator?
> Thanks....
> Bert
> 
> Bert Katzung
> katzung1@home.com
> www.astronomy-images.com
> 
> ----- Original Message -----
> From: "Mike Cook, AF9Y" <mwcook@concentric.net>
> To: <astro-photo@seds.org>
> Sent: Monday, 26 November, 2001 5:56 PM
> Subject: [APML] OK - here's your blue Veil Nebula
> 
> 
> > Chuck and others,
> >
> >     After a bit of research and discussion, I've come to the
> > conclusion that the Veil nebula has no OIII and that my
> > mapping into the hot color space was therefore incorrect.
> > Based on only Ha/Hb, I've readjusted the mapping and offer
> > the following new image:
> >
> > http://www.webcom.com/af9y/veilrgb.htm
> >
> >     You can compare it to the Robert Bickel tri-color that
> > Chuck made reference to:
> >
> > http://www.ccnet.com/~rbickel/photo/veil.html
> >
> >     Of interest is the Ha/Hb mix required to produce the
> > pink/violet type color seen in this image.  Here is a
> > chromaticity chart showing how the color is produced:
> >
> > http://www.webcom.com/af9y/chrom.jpg
> >
> >     Note that it takes a mix of  2.5 parts Ha to 1 part Hb for
> > this color range.  You can experiment with other emission
> > line mixes using the following CIE calculator:
> >
> > http://www.flatnet.org/glossary/ciecalculator.htm


Mike Cook, AF9Y
http://www.webcom.com/af9y
mwcook@cris.com




--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>