The Sharpless catalog is a list of 313 H II regions (emission nebulae ) intended to be comprehensive north of declination −27°. (It does include some nebulae south of that declination as well.) The first edition was published in 1953 with 142 objects (Sh1), and the second and final version was published by US astronomer Stewart Sharpless in 1959 with 312 objects. Sharpless also includes some planetary nebulae and supernova remnants , in addition to H II regions.
6-685: Simeis 147 , also known as the Spaghetti Nebula , SNR G180.0-01.7 or Sharpless 2-240 , is a supernova remnant (SNR) in the Milky Way , straddling the border between the constellations Auriga and Taurus . It was discovered in 1952 at the Crimean Astrophysical Observatory by Grigory Shajn and his team using a Schmidt camera and a narrowband filter close to the Hydrogen Alpha transmission line. It
12-408: A filamentary structure. The remnant has an apparent diameter of approximately 3 degrees , an estimated distance of approximately 3000 (±350) light-years , and an age of approximately 40,000 years . At that distance, it spans roughly 160 lightyears. It is believed that the stellar explosion left behind a rapidly spinning neutron star known as pulsar PSR J0538+2817 in the nebula core, emitting
18-586: A strong radio signal. Sharpless Catalog In 1953 Stewart Sharpless joined the staff of the United States Naval Observatory Flagstaff Station , where he surveyed and cataloged H II regions of the Milky Way using the images from the Palomar Sky Survey . From this work Sharpless published his catalog of H II regions in two editions: the first in 1953, with 142 nebula; and
24-465: Is difficult to observe due to its extremely low surface brightness. This discovery was part of a survey conducted between 1945 and 1955, most likely using captured German equipment, as the observatory was practically destroyed during WWII. The Schmidt camera had a field of view of 175'. Many previously unknown hydrogen nebula were discovered this way, as they are not readily visible in regular photographs. The nebulous area has an almost spherical shell and
30-439: The second and final edition in 1959, with 312 nebulae. Sharpless coordinates are based on the star catalogs Bonner Durchmusterung (BD) and Cordoba Durchmusterung (CD), but the second release was adjusted to the 1900 epoch. In the second release, some coordinates for southern hemisphere regions have an uncertainty over 1 minute of arc. This can make them difficult to find, so a revised catalog called BFS (Blitz, Fich and Stark)
36-671: Was released with 65 new regions and about 20 removals. Most of the removed items were the aforementioned nebula or remnants. The 312 items in Sharpless sometimes overlap with the 110 Messier objects (M), 7,840 objects in the New General Catalogue (NGC), the Caldwell catalogue (itself a "best of" from other catalogues, with 109 items), and the RCW catalog . Contemporary catalogs were Gum and RCW , but they mainly covered
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