SH2-155 - The Cave Nebula in SHO (Cfosterstars)

SH2-155 - The Cave Nebula in SHO

This is not my best effort. I had lots of issues with this data set. I had some serious flat fielding issues and Moiré fringe fixed pattern noise in the SII and OIII master light frames and several unresolved and large dust donuts that had to be removed through processing. I will need to go back next season and collect better data. This is a very dim target and there is very weak OIII and SII data. I could probably improve on the processing, but due to the flats issues, I am reluctant to sink a lot of time. I would rather wait and get more and better data next year.

Sh2-155 (also designated Sharpless 155 or S155) is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. It is widely known as the Cave Nebula, though that name was applied earlier to Ced 201, a different nebula in Cepheus. Sh2-155 is an ionized H II region with ongoing star formation activity, at an estimated distance of 725 parsecs (2400 light-years) from Earth.

Sh2-155 was first noted as a galactic emission nebula in 1959 in the extended second edition of the Sharpless catalogue, being a part of the much larger Cep OB3 Association. Although Sh2-155 is relatively faint for amateur observation, some of its structure may be seen visually through a moderately sized telescope under dark skies.

Sh2-155 lies at the edge of the Cepheus B cloud (part of the Cepheus molecular cloud), and is ionized by young stars from the Cep OB3 association. It has been suggested that radiation from the hot O-type star HD 217086 is compressing the region, triggering the formation of a new generation of stars. A study of the region's young stellar objects by the Chandra X-ray Observatory and Spitzer Space Telescope shows a progression of stellar ages in front of the cloud, supporting the hypothesis of triggered star-formation.

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Status	Advanced success
Started	...
Astrometry.net job	3013092
PixInsight job	5JNFHKGV5PSA56XKE34HQNP0CV1JK0CZ
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	22h57m40s.811
RA (top/left)	22h56m16s.417
RA (top/right)	22h56m15s.290
RA (bottom/right)	22h59m03s.958
RA (bottom/left)	22h59m07s.523

Dec (center)	+62°36′12″.20
Dec (top/left)	+62°49′39″.18
Dec (top/right)	+62°22′53″.43
Dec (bottom/right)	+62°22′41″.29
Dec (bottom/left)	+62°49′26″.74

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