Introduction | Map | My Own Photos | My Own Observations | References
On this page I collect my observations of the galactic reflection nebula NGC 2261, called Hubble's Variable Nebula, in the constellation Monoceros/Unicorn.
The galactic reflection nebula NGC 2261 in the constellation Monoceros / Unicorn, is called Hubble's Variable Nebula because it changes in detail. But this is only visible in large telescopes. The special thing about this nebula is its shape, which resembles a comet. The nebula is illuminated by the star R Monocerotis (R Mon), which is not directly visible itself.
In a Vespera mosaic, NGC 2261 can be observed together with NGC 2264/Cone Nebula. Actually, a small Vespera mosaic was the only possibility for me to find the Cone Nebula.
| NGC 2261 | NGC 2264 | Cone Nebula | ||
| Size: 3' x 2' (Wikipedia) Distance: 2,600 light years (Wikipedia) Ranking: ** (Stoyan) |
Size: 20' (Stoyan) Distance: 2,500 light years (Stoyan) Ranking: *** (Stoyan) |
Size: 10' (Wikipedia) Distance: 2,700 light years (Wikipedia) Ranking: --- |
NGC 2261, called Hubble's Variable Nebula, in the constellation Monoceros/Unicorn (Image Courtesy of SkySafari Astronomy, www.simulationcurriculum.com)
NGC 2261, called Hubble's Variable Nebula, in the constellation Monoceros/Unicorn, detail (Image Courtesy of SkySafari Astronomy, www.simulationcurriculum.com)
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NGC 2261 - Feb 16, 2020, processed |
NGC 2261 - Feb 16, 2020, processed |
NGC 2261 - Feb 16, 2020, processed |
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NGC 2261 - Mar 8, 2021 |
NGC 2261 - Mar 8, 2021 |
NGC 2261 - Mar 8, 2021 |
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NGC 2261 - Mar 8, 2021, processed |
NGC 2261 - Mar 8, 2021, processed |
NGC 2261 - Mar 8, 2021, processed |
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NGC 2261 (top right) with NGC 2264 (left), Mar 28, 2024 - original, 2250s, small mosaic, Dual Band Filter |
NGC 2261 (top right) with NGC 2264 (left), Mar 28, 2024 - large, 2250s, small mosaic, Dual Band Filter, photo left processed (PSE) |
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Ditto, photo additionally processed (DN) - large |
Ditto, photo additionally processed (DN+PSE) - large |
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NGC 2261 (top right) with NGC 2264 (left), Apr 11, 2024 - original, 4570s, small mosaic, Dual Band Filter |
NGC 2261 (top right) with NGC 2264 (left), Apr 11, 2024 - large, photo left processed (PSE) |
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Ditto, photo additionally processed (DN) - large |
Ditto, photo additionally processed (DN+PSE), poor quality - large |
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NGC 2261 (bottom right) with NGC 2264 (top left), Mar 18, 2025 - 2000, 1 h |
NGC 2261 (bottom right) with NGC 2264 (top left), Mar 18, 2025 - 2000, 1 h, processed |
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NGC 2261 (bottom right) with NGC 2264 (top left), Mar 18, 2025 - 2000, 1 h, processed and denoised (PAI) |
NGC 2261 (bottom right) with NGC 2264 (top left), Mar 18, 2025 - 2000, 1 h, processed and denoised (PAI), made brighter |
