Do you know your State Astronomical Object? Apparently, in 2019 the Oklahoma passed legislation that the Rosette was theirs!
The Rosette Nebula HII region and the associated open cluster NGC 2244 need little introduction (especially to Okies?), as at nearly three times the size of the full moon, and a very popular target. At 5200 light-years away, the cluster of 2500 stars is 36 light-years across, while the nebulosity is 130 light-years across, for a grand total of 10,000 solar masses. The O-type stars are super hot and generate the radiation and stellar winds that expand and illuminate the nebulosity. Typical of open clusters, it is young, a mere 5 million years (only about 1/1000 the age of our own Sun). The nebula will disperse in the next few million years, so observe it while you can!
A survey by the Chandra X-ray Observatory revealed many
new-born stars, including the massive O-type stars HD 46223 and HD 46150, which are primarily responsible for blowing the ionized bubble. Most of the star-formation is occurring in the dense molecular cloud to the south east of the bubble.
There was an issue however, with the size of the hole in the Rosette, as it appeared to be only one-tenth the size it should be, based on the strength of stellar winds and the age of the star cluster. However,
computer simulations with a thin disk model seem now to have settled the issue:
Finally, a bit about names.- The Rosette is also known as the Skull Nebula. I don’t know about you, but the Rosette is much better name to me, and I don’t see a skull, though the hole seems heart shaped to me.
- The open cluster is also known as the Satellite Cluster, I can’t find the source for this name, but I assume it because the stars seem to be placed as if they are revolving around the central star, like satellites?
- The Rosette nebulosity was discovered in bits and pieces, NGC 2237, 2238, 2239 and 2246. NGC2237, as the first discovered, now gets the credit for the whole nebula.
Inisight Observatory Data: A big shout to out to @Insight Observatory for this incredible purchased data, while I wait on some clear skies.- Optics: AG10 CDK F6.7 f=1665mm
- Camera: PLI Proline 6303
- Mount: SkyWatcher EQ8RH
- Gemini Observatory, Lijiang, China
- Imaged by Alpha Zhang
- 2021-10-22 to 11-01
- 84 images for 18 h total
- RGB: 6 each at 300 s, Ha: 12 x 900 s, OIII: 25 x 900s, SII = 29 x 900 s
My Processing- DeepSkyStacker: I did all calibrations, registration and stacking in DSS.
- StarTools: I processed the nebulosity as SHO mapping directly to RGB, with no cross-mixing of channels, as all SHO channels were strong with good S/N. StarTools has a nice feature called purple cap, which helped with the color. I processed the the RGB data separately for the stars. For both I did a background wipe, film emulation stretch, deconvolution and initial color in StarTools.
- Photoshop
- I used StarXterminator to remove stars from the SHO nebulosity.
- I deblurred the nebulosity using APF-R (a multi-scale unsharp mask used by NASA).
- I applied selective color and vibrance and levels to both layers
- I used NoiseXterminator to reduce noise and increase detail and Camera Raw to reduce color noise.
- I added stars ontop with Screen mode, as Linear Dodge (add), which I often use, made the stars way too bright.
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