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Contains:  Hubble's variable neb, NGC 2261
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NGC 2261 - Hubble's Variable Nebula, 


            Gary Imm
NGC 2261 - Hubble's Variable Nebula

NGC 2261 - Hubble's Variable Nebula

Technical card

Resolution: 3704x2739

Dates:March 27, 2019March 28, 2019

Astrodon Blue 31mm Gen2 I-Series: 90x30" (gain: 139.00) -20C bin 1x1
Astrodon Green 31mm Gen2 I-Series: 90x30" (gain: 139.00) -20C bin 1x1
Astrodon Lum 31mm Gen2 I-Series: 210x30" (gain: 139.00) -20C bin 1x1
Astrodon Red 31mm Gen2 I-Series: 90x30" (gain: 139.00) -20C bin 1x1

Integration: 4.0 hours

Avg. Moon age: 21.97 days

Avg. Moon phase: 51.93% job: 2627978

RA center: 6h 39' 9"

DEC center: +8° 45' 0"

Pixel scale: 0.391 arcsec/pixel

Orientation: 270.164 degrees

Field radius: 0.250

Locations: Backyard (Mag 20.8 - New Moon), Onalaska, Texas, United States

Data source: Backyard


This object is a variable reflection nebula located 2500 light years away in the constellation of Monoceros. The nebula, one light-year across, is a fan-shaped cloud of gas and dust which is illuminated by a 10th magnitude star (R Monocerotis) on the left side of the nebula.

This object is unique because its light pattern changes with time. Dense concentrations of dust near the star cast shadows out into the nebula. As the dust moves the shadows change, giving rise to the brightness variations first observed by Dr. Edwin Hubble.

This object is sometimes compared to a comet, but it looks much prettier than that to me. The illuminated bright nebulosity varies in color from purple at the top to blue in the middle to brown at the bottom. I also like the sharp edges at the left side of the nebula and how the object looks like it is on fire, as if the bright star is burning and a wind is blowing the resulting smoke to the right and diffusing it.

I find it very curious that this nebula is so unsymmetric. Scientists speculate that a symmetrical counterpart of this fan-shaped nebula exists, but that we cannot see it because it is heavily obscured from our view by dust. It doesn't appear that way to me and I can't really make sense of this unique shape.



Gary Imm
License: None (All rights reserved)

Sky plot

Sky plot


NGC 2261 - Hubble's Variable Nebula, 


            Gary Imm