Carbon star T-Lyr and saturation
Posted 10 September 2007 - 12:33 AM
was checking out a few carbon stars the other night
T-Lyr looked metallic red in my 8" SCT
here's a very conservative linear process of T-Lyr
attempting to recreate the color:
here it is stretched with an aggressive increase in saturation using a layer mask, and a slight hue shift:
FS102, IDAS LPR, SX-AO, H9C; 60x15 sec.
Los Alamitos, CA 9/2/07.
unfortunately all my attempts to stretch the image and bring out some of the background stars
rendered the star orange as the red level was maxed, and the only way it can be brightened above the background stars is to bring up the blue and green levels.
Posted 10 September 2007 - 04:20 AM
The thread brought an immediate smile to my face since I also have a little ongoing project surrounding carbon stars: http://www.perseus.g...Star-Carbon.htm ... and which includes T-Lyr.
After a non-linear stretch, one must indeed saturate to bring up the proper colour since the Lum during layering will wash out the RGB layer. I usually go for around +30 on the saturation and which provides me with a good net result.
Posted 10 September 2007 - 04:24 AM
... if it's not heresy, can you keep the second (processed version, cut out ONLY T Lyrae, fix it, and then paste it back where it belongs ?
Posted 10 September 2007 - 07:25 AM
Posted 10 September 2007 - 12:03 PM
mark, it is heresy! but i'll give it a try, or i can do it with layer masks so we avoid the ugly paste word
eric i tried boosting the saturation with a layer mask, and using a layer mask for the color, but not in normal mode. i'll see if i can get it a bit more red that way.
anthony, that is funny. i had observed most of the stars you imaged when i took the T LYR shot. the thing is that to my eye, T-LYR, and a few of the others are really a very deep, almost stoplight, red. even with your saturation boost, T-LYR comes out very orange. tell me what you think visually.
Posted 10 September 2007 - 02:13 PM
using a layer mask to bring the linear on to the composite
then selective curve to the star and saturation
trying to preserve the color i see in the eyepiece
thanks for the suggestions
Posted 10 September 2007 - 03:12 PM
Posted 11 September 2007 - 04:49 AM