DEEP SKY WEST ASTROPHOTOGRAPHY FORUMS

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M101 via RH305 + FSQ

M101 lum data merged from FSQ and RH305 and RGB data from RH305.

Astrobin: https://www.astrobin.com/410968/D/?nc=user

Scott Stirling
Graham, NC

Uploaded files:
  • M101_2019_abe_RGB_stretch_r_Preview01.jpg

I personally find that processing small (relative to the FOV) galaxies quite challenging to carry from luminance (looks great) to a nice color image LRGB.  I often feel I'm increasing blue and teal/cyan on galaxies without picking up the reddish highlights, even with masks and color-aware selectors.   For the RH-305 and SBIG 16803, a galaxy (unless it's Andromeda) is usually an image where the main object of interest, on a full frame CCD, takes up 1 million or less of the 16 million pixels of the entire FOV, or about 1/16th of the image area!

Any tips for processing galaxies welcome.

Scott Stirling
Graham, NC

Try to use ArcSin Stretch in Pixinsight to pull out the color on the RGB (use 2-3 application to get it right vs one big change) and then add the Luminance data with the LRGB Combination with just the L selected and apply to ASS applied image.   To bring out more detail use HDRMT on the Lum (non-linear) before adding.    This is pretty much a game changer to get color into the images.

This is a rough example of that approach.   This is still a work in progress.

Uploaded files:
  • Image51.jpg