Re: [APML] The Halo of the Dumbbell

[Stuart Heggie <stuart.j.heggie@sympatico.ca>]

Rob - it just never stops! There is so much more in this image that I 
bet a lot of astro-imagers would not have recognized it. I have heard it 
called the apple core nebula and your image really brings out that 
metaphor. I would like to say thanks for sharing the processing steps 
but I think I only understood about half of them. So much to learn!

Thanks!
Stuart

Robert Gendler wrote:

> 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.
>  
> Rob Gendler
> Email: robgendler@att.net <mailto:robgendler@att.net>
> Web site: http://www.robgendlerastropics.com/
>
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>
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