ASTRO: Fainter than Faint update

sound logic - trully wonderful photo.


Richard Crisp wrote:

"George Normandin" wrote in message
...
"Richard Crisp" wrote
......
So the image is an 'add' of the O and H images? Do the separate filter
views show different structure? It sure looks like some shock wave
action in your image.

I should have been more explicit about my prescription for the color
assignment............


OK, it all makes sense now.

I've always called ionized hydrogen "electro-pink" in color because of the
red/blue mix.

in fact you bring up a something that reminds me of a point I have been
meaning to make: many folks take Halpha and then want to "work that into"
their RGB image.

usually I see them either use it for luminance for a nebula shot or perhaps
add it to the red channel.

the correct hue of the hydrogen clouds is really determined by the ratio of
Halpha to Hbeta and that is about 3:1

if you only insert the Halpha into red, then it skews the colors to the
redish/salmon color instead of that magenta pinkish color when you have the
Hbeta present.

The hbeta can be approximated (recreated) in its effect by simply using
about 20-30% of the Halpha blended with the Blue channel or with OIII to use
for the blue channel.

that will recreate that Halpha/Hbeta ratio in the Red/Blue channels to
better match reality.


George N