North America Nebula (NGC 7000): A New Processing Approach (Gary Lopez)

North America Nebula (NGC 7000): A New Processing Approach

The North America Nebula has been studied by astronomers and imaged by astrophotographers for a long time. In 1786 astronomer William Herschel described a large emission nebula in the constellation Cygnus as a “faint milky nebulosity scattered over this space, in some places pretty bright.” Forty-three years later, in 1829, his son, John Herschel, listed it in their catalog. In 1890 astrophotographer Max Wolf recognized a familiar shape in his long-exposure photograph of the region and called it North America Nebula.

I got lucky in September with five clear nights and excellent seeing. I was able to collect more than 35 hours of data. For this image I used only those sub lights with HFR ranging from 1.6-2.0, totaling about 24 hours of integration. With these excellent data I decided to experiment with different star processing approaches. The effort yielded six different version of the image. What I have posted today is my favorite. The processing approach of this version was a modified Tone Mapping process where starless, narrowband channels are married with a RGB/Master Luminance Masked image using the NBRGB script in Pixinsight. The resulting image has natural star color, fine detail, a soft, liquid-like transparency in the nebular clouds, and a glow that seems to emanate from inside.

I will post all six approaches as a processing study on Astrobin in the near future.

B

Description: Cleaned up a little cropping problem

Uploaded: ...

C

Description: Tweaked a few areas to pop contrast.

Uploaded: ...

D

Description: Changed black point in central dust lane

Uploaded: ...

E

Description: Cleaned up crop and color temperature of ridges.

Uploaded: ...

F

Description: Added additional data and reprocessed master luminance and cleaned up some star artifacts

Uploaded: ...

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Status	Advanced success
Started	...
Astrometry.net job	3906186
PixInsight job	NYA1ZDD2L0YWUXEE85W7TBBZWVW75L2G
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	20h56m18s.22
RA (top/left)	20h46m34s.37
RA (top/right)	20h55m45s.35
RA (bottom/right)	21h06m10s.47
RA (bottom/left)	20h56m53s.27

Dec (center)	+44°24′47″.1
Dec (top/left)	+43°59′47″.3
Dec (top/right)	+42°37′19″.0
Dec (bottom/right)	+44°46′40″.5
Dec (bottom/left)	+46°12′16″.3

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