Various Collections for Comparison:I am going over the Sharpless2 Objects again with my new C11 and a few more years experience.
The current image with the C11 focuses on the details of the small nebula in the starless mouse-over.
This version is about 3h of Ha and RGB and processed with StarX and BlurX and GHS.
Have photographed this before as part of the series. Below was 6h taken with my Tak 180ED in 2015 with a CCD and reprocessed in 2021 with noise reduction.
Sh2 107 H-alpha RGB Basic Information From GalaxyMap about Sh2 107:Very little about this tiny and very faint nebula located well below the galactic plane appears in the scientific literature.
Sharpless suggests that Sh 2-107 may be ionised by the B2 class
HD 197460. SIMBAD says that this star is actually a B0.5 Ib supergiant and according to
this catalog entry, the star has 9.5 +/- 0.2 solar masses and an age of 22.6 +/- 2.7 million years.
Humphreys gives a distance estimate of 2000 parsecs for HD 197460 (and a slightly different class of B1 II(N)). This is at the lower limit of the distance estimate for Sh 2-107 so it is indeed conceivable that this star ionises the nebula.
This object can be detected weakly as a diffuse nebula at radio frequencies.[1]
Notes: 1.
^ Fich, Michel (1993). "A VLA survey of optically visible galactic H II regions", The Astrophysical Journal Supplement Series, Vol. 86, 475-497. [[url=
http://adsabs.harvard.edu/abs/1993ApJS...86..475F]1993ApJS...86..475F]
Distance Estimates:2800 pc +/- 900 [[url=
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1995AJ....109.2611C]1995AJ....109.2611C]
GENERAL NOTE ON SHARPLESS2 OBJECTS>>>>>>>>>>>>>
There are 313 Sh2 objects. All now imaged by yours truly. These are basically the Hydrogen Alpha and other ionized nebulae around the edge of the Milky Way.
This is my collection:Sharpless2Wide-Angle Hydrogen Alpha Nikon Image Sh2 79-171Please note there is also a Sharpless2 Group with now more than 3000 examples.
Sharpless2 GroupOther useful links include:
Gary Imm's CollectionGalaxyMap's CollectionThe Sharpless CatalogThe MDW H-alpha Sky SurveyReiner Vogel's detailed observing catalogHope you enjoy these obscure but interesting objects...
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