----- Original Message -----
Sent: Sunday, April 21, 2002 8:38
PM
Subject: Re: [APML] M51 RGB (only)
Howdie folks,
So.... following Rob's
lead, here goes: I have been putzing around with color information via a CCD
instead of film... guess what? Noise is still enemy #1. So the same rules
apply here that apply to film... shoot lots of images and average. I gathered
up all the bits and pieces that I had on M-51 and did all the "reduction"
process on them... this is the same as cleaning up photo images by getting rid
of vignetting, dust spots, etc etc etc.
Then these files, all in 16
bit info, were imported into Registar to average and merge into a 16 bit RGB.
By combining the RGB before any curves or post processing was done, the color
balance as dictated by the filters and exposure times should be pretty much
"locked in."
Then I took the file
into PS and gently applied curves and some level corrections for the black end
point to compress the data. I applied a slight amount of saturation to the
image. Basically that's it. What I got, I think, is a pretty close
approximation of the true colors of M-51 since this is "pure" RGB... no L, no
nothing. Note that the little galaxy at the bottom is very blue... active star
formation or something, and there is an interesting blue arm from the main
galaxy near the companion... in color you can see from this that M-51 is
probably in front of the companion which is a different color... in the 200"
image you can see this as a string of material from the main galaxy but it is
in B&W.
Tony