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[APML] The Halo of the Dumbbell



Hi all,
I've uploaded a new image of M27 capturing the extensive
outer halo of faint emission using 8 hours of hydrogen-alpha
exposure plus several hours for the RGB component.
http://www.robgendlerastropics.com/M27HA.html

I realize this was done before by Roland but it was fun
and a real challenge to do.

The processing steps were roughly as follows
 
1) After combining the h-alpha frames DDP was applied in Maxim.
2) The 16 bit file was then processed aggressively in photoshop
using multiple rounds of curves, and levels to enhance the faint
halo.  
3) H-alpha was then combined with the G and B channels.
4) A luminance was made from a composite of the HA data (#1)
and a LR processed version for the central region (5 iterations).
5) Unsharp mask was applied to the luminance.
6) LRGB was then made in PS.
7) A "minimum filter" was applied to the "red" channel to reduce
the numerous little red stars and red halos that result from the above
process.
8) Finishing touches were applied in PS.
 
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