A cluster of Sharpless2 Objects.
From
GalaxyMap:Sh 2-16 is part of the Sh 2-15 to Sh 2-20 complex of HII regions located in the Sgr OB5 association in the Sagittarius arm. It appears to be ionised by the O9.5 V star LSS 4381.
Sh 2-17 is part of the Sh 2-15 to Sh 2-20 complex of HII regions located in the Sgr OB5 association in the Sagittarius arm.There are no papers suggesting ionising stars for Sh 2-17 and there are no OB stars in this direction in the Reed OB star catalog either. However, the infrared cluster [url=
http://simbad.u-strasbg.fr/simbad/sim-id?Ident=[DB2000]+58][DB2000] 58[/url]
appears to be embedded in the nebula and may contain the ionising stars.
Sh2 18: This small nebula is part of the Sh 2-15 to Sh 2-20 complex of HII regions located in the Sgr OB5 association in the Sagittarius arm. It lies next to RCW 140 (Sh 2-19).No ionising stars are cited in the scientific literature but the nebula is believed to contain the infrared cluster [url=
http://simbad.harvard.edu/simbad/sim-id?Ident=[DB2000]%201][DB2000] 1[/url]
which may perhaps contain ionising stars.
Sh2 19: This nebula is part of the Sh 2-15 to Sh 2-20 complex of HII regions located in the Sgr OB5 association in the Sagittarius arm.GENERAL NOTE ON SHARPLESS2 OBJECTS>>>>>>>>>>>>>
I have been on a project for several years now to image all the Sharpless2 Objects that I can see from my location near San Francisco. I chose these because they are visible in light polluted areas. These objects generally represent left over Hydrogen along the edge of the Milky Way that has gotten molded into interesting shapes.
There are 313 Sh2 objects.
As of the date when this image was posted:
I had imaged 275 (88%).
There are 12 too diffuse/large to image with my set up (Sh2 111, 117, 122, 131, 132, 145, 178, 218, 221, 230, 268 and 310). I may look for other images so I can get a complete collection or make my best shot for completeness.
There are 5 that are never above 14 DEG (Sh2 2-6) [Edit 7/12/21- I can get these now with pier upgrades and the images are completed as best as I can].
These remainder are in Expert Scheduler waiting for them to pass by.
The first one was taken on December 23, 2013.
Many were taken with my old Tak 180 ED, which had a wide field of view, but was replaced with my Stellarvue 130, which is more narrow field. I have also taken two very wide field HA images with my Nikon D800 and a 50mm lens.
This is my collection:
Sharpless2Wide-Angle Hydrogen Alpha Nikon Image Sh2 79-171Please note there is also a Sharpless2 Group with now more than 1500 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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