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Ghost Nebula (SH2-136), 





    
        

            KuriousGeorge
Ghost Nebula (SH2-136)

Ghost Nebula (SH2-136)

Technical card

Resolution: 4038x4053

Dates:Sept. 22, 2019Sept. 23, 2019Sept. 24, 2019Sept. 30, 2019

Frames:
Astrodon 50 mm G: 10x900" -30C bin 1x1
Astrodon 50mm B: 12x900" -30C bin 1x1
Astrodon 50mm L: 24x900" -30C bin 1x1
Astrodon 50mm R: 12x900" -30C bin 1x1

Integration: 14.5 hours

Darks: ~20

Flats: ~80

Flat darks: ~80

Bias: ~20

Avg. Moon age: 18.19 days

Avg. Moon phase: 27.48%

Mean SQM: 21.40

Mean FWHM: 2.00

Astrometry.net job: 2964940

RA center: 21h 16' 29"

DEC center: +68° 15' 14"

Pixel scale: 0.467 arcsec/pixel

Orientation: 178.007 degrees

Field radius: 0.371

Locations: KG Observatory, Julian, CA, United States

Data source: Backyard

Description

Recently a few folks on Astrobin suggested I try the elusive Ghost Nebula (SH2-136). This is a challenging LRGB object with virtually no signal in Ha or OIII. Long integration in dark skies is very helpful.

My goal was to collect my normal 6 hours of L and 3 hours of each RGB channel (15 hours total) with FWHM on 15 minute subs <= 2".

During the 10-day dark window, the first 3 days were great and then it was cloudy for 5 days. After that, the night time air temperature dropped 20 degrees and the ground was still warm. That apparently was the perfect recipe for 3"+ FWHM seeing.

It steadied enough on 9/30 to collect another hour of L and to fill in some RGB.

Adam Block's excellent capture with his 32" at 9,157' was my reference...

Adam Block's Ghost Nebula

What you see here is 24" at 4,200' in 21.4 SQM skies. It was a long 10 days. I very much appreciated the requests and enjoyed the challenge.

Comments are very welcome!

"Spooky shapes seem to haunt this starry expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds faintly visible in dimly reflected starlight. Far from your own neighborhood on planet Earth, they lurk at the edge of the Cepheus Flare molecular cloud complex some 1,200 light-years away. Over 2 light-years across the ghostly nebula and relatively isolated Bok globule, also known as vdB 141 or Sh2-136, is near the center of the field. The core of the dark cloud on the right is collapsing and is likely a binary star system in the early stages of formation."

Comments

Author

KuriousGeorge
KuriousGeorge
License: None (All rights reserved)
3538
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Ghost Nebula (SH2-136), 





    
        

            KuriousGeorge