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Contains:  NGC 281
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NGC-281 (Pacman Nebula), 


            Joel Shepherd
NGC-281 (Pacman Nebula)

NGC-281 (Pacman Nebula)

Technical card

Resolution: 1280x1147

Dates:Oct. 11, 2016

Astrodon 5nm H-alpha: 15x300" -10C bin 1x1
Astrodon 5nm Olll: 15x300" -10C bin 1x1

Integration: 2.5 hours

Avg. Moon age: 9.63 days

Avg. Moon phase: 73.02%

Bortle Dark-Sky Scale: 6.00 job: 1304944

RA center: 0h 52' 32"

DEC center: +56° 45' 3"

Pixel scale: 2.433 arcsec/pixel

Orientation: 110.995 degrees

Field radius: 0.581

Locations: Home, Seattle, WA, United States


Subject: NGC-281 (Pacman Nebula), near Cassiopeia. Discovered in 1883 by E.E. Barnard, NGC-281 is at a distance of ~9500 light years, and is about 48 light years across. Its emissions are primary driven by the open star cluster IC-1590, while the darkest regions are primarily dust and are areas of active star formation. [Derived from Wikipedia entry]

Capture notes: I've started doing a few "One Night Wonders": capturing what I can in a single night and making the most of processing. In some cases it's simply because the commitment to a multi-night effort is too much. In this case, as it turned out, we didn't even get another night! There has been one clear evening in Seattle in the month of October. Other than a moon approaching full, I thought the skies were pretty clear. Early on in processing, it was evident that some thin clouds passed over while capturing the O-III lights.

Processing: This is HOO, with green augmented with a little HA, and the O-III boosted a bit in blue. The O-III required a pretty heavy hand on noise reduction. Luminance (full stack of all lights) had some weird speckling artifacts which PixInsight's cosmetic correction dealt with. Combined HA and O-III "tone maps", boosted saturation and darkened hues, applied luminance and that was about it.



Joel Shepherd
License: Attribution Creative Commons

Sky plot

Sky plot


NGC-281 (Pacman Nebula), 


            Joel Shepherd