Sh 2-283 to Sh 2-286 are all part of one star formation region. [1]
This region is associated with the star cluster Dolidze 25. [2]
A good recent article summarising Spitzer infrared observations of Sh 2-284 concludes that Dolidze 25 has a distance of 5500 parsecs and an age of 6 million years. [3]
Notes
1. Russeil, D., Adami, C., & Georgelin, Y. M. (2007). "Revised distances of Northern HII regions", Astronomy and Astrophysics, Vol. 470, 161-171. [2007A&A...470..161R]
2. Lennon, D. J., Dufton, P. L., Fitzsimmons, A., et al. (1990). "Dolidze 25 - A metal-deficient galactic open cluster", Astronomy and Astrophysics, Vol. 240, 349-356. [1990A&A...240..349L]
3. Puga, E., Neiner, C., Hony, S., et al. (2007). "Massive star formation in the outer Galaxy: S284", IAU Symposium, Vol. 237, 465-465. [2007IAUS..237..465P]
Above from Galaxymap.
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 312 Sh2 objects and those below 70 and above 283 are generally too low on the horizon for me to image... this leaves me 212 that are feasible... and I have imaged all of these but the 13 of these are too big for my system. .
This image was the last image in the series and I may add some more if I can get closer to the horizon... 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.
This is my collection:
Sharpless2Please note there is also a Sharpless2 Group with now more than 1000 examples.
Hope you enjoy these obscure but interesting objects...
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