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Contains:  NGC 1501
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NGC 1501 Oyster Planetary Nebula in HaOIIIRGB

Technical card

Dates:Dec. 18, 2019Dec. 21, 2019Dec. 22, 2019

Astrodon Blue Tru-Balance E-Series Gen 2: 30x60" (gain: 0.00) -20C bin 1x1
Astrodon Green Tru-Balance E-Series Gen 2: 30x60" (gain: 0.00) -20C bin 1x1
Astrodon Ha 5nm: 303x120" (gain: 200.00) -20C bin 1x1
Astrodon OIII 3nm: 299x120" (gain: 200.00) -20C bin 1x1
Astrodon Red Tru-Balance E-Series Gen 2: 30x60" (gain: 0.00) -20C bin 1x1

Integration: 21.6 hours

Darks: ~50

Flats: ~50

Bias: ~250

Avg. Moon age: 23.89 days

Avg. Moon phase: 33.02%

Bortle Dark-Sky Scale: 7.00

Basic astrometry details job: 3256759

RA center: 4h 6' 59"

DEC center: +60° 55' 12"

Pixel scale: 0.325 arcsec/pixel

Orientation: 230.998 degrees

Field radius: 0.125 degrees

Resolution: 2165x1732

Locations: Backyard White Zone Observatory, Taylor, MI, Michigan, United States

Data source: Backyard


This is probably one of the most challenging objects I have ever captured. I know it doesn't look like much, but is only 0.863' in size. With my image scale of 0.64"/pixel, it was very tiny in the frame.

Discovered by William Herschel in 1787, NGC 1501 is a planetary nebula that is just under 5000 light-years away from us. Astronomers have modelled the three-dimensional structure of the nebula, finding it to be a cloud shaped as an irregular ellipsoid filled with bumpy and bubbly regions. It has a bright central star that can be seen easily in this image, shining brightly from within the nebula’s cloud. This bright pearl embedded within its glowing shell inspired the nebula’s popular nickname: the Oyster Nebula.

While NGC 1501's central star blasted off its outer shell long ago, it still remains very hot and luminous, although it is quite tricky for observers to spot through modest telescopes. This star has actually been the subject of many studies by astronomers due to one very unusual feature: it seems to be pulsating, varying quite significantly in brightness over a typical timescale of just half an hour. While variable stars are not unusual, it is uncommon to find one at the heart of a planetary nebula.



Douglas J Struble
License: None (All rights reserved)

Sky plot

Sky plot


NGC 1501 Oyster Planetary Nebula in HaOIIIRGB, 


            Douglas J Struble