The Sharpless Catalog

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Sh 2-271

Coordinates: (197.77°, -2.31°)
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Sh 2-271 contains the infrared cluster [BDS2003] 82 and is embedded in a 9800 solar mass molecular cloud. This is an HII region, not a planetary nebula as is sometimes reported.

Sh 2-271 and the much fainter Sh 2-272 are both part of the Avedisova star formation region 197.77-2.31. She concludes that these nebulae are ionised by two uncatalogued stars: MFJ Sh 2-271 1 (O9 V) and MFJ Sh 2-272 3 (B1 V).

Sh 2-272

Coordinates: (197.81°, -2.28°)
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Sh 2-272 is an HII region, not a planetary nebula as is sometimes reported.

Sh 2-271 and the much fainter Sh 2-272 are both part of the Avedisova star formation region 197.77-2.31. She concludes that these nebulae are ionised by two uncatalogued stars: MFJ Sh 2-271 1 (O9 V) and MFJ Sh 2-272 3 (B1 V).

Sh 2-273

Coordinates: (202.92°, 2.17°)
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The Fox Fur nebula is associated with the Christmas Tree star cluster NGC 2264, dominated by the O7Ve multiple star system S Monocerotis (S Mon). This region, which is part of the larger Mon OB1 association, also includes the famous Cone nebula, visible at the bottom of the image.

You can find out more about this region in the Mon OB1 section of the description of the Fox Fur and Rosette (210° - 200°) sector in the Commentary on the Galactic Plane.

A better image of the Fox Fur nebula region can be found here. A wide scale view that shows the huge region of nebulosity in this direction is here.

The relatively close distance estimate suggests that Mon OB1 is part of the Orion spur.

Sh 2-274

Coordinates: (205.2°, 14.3°)
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The Medusa nebula, Abell 21, is a 8800 year old planetary nebula.

These images from Dean Salman also show the larger surrounding nebulosity.

Sh 2-275

Coordinates: (206.3°, -2.11°)
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This is the Rosette Nebula, one of the most beautiful sights in the Milky Way. The star cluster NGC 2244, part of the Mon OB2 association, contains about 2000 stars and forms a blister at one end of the 130 thousand solar mass Rosette molecular cloud. About 30 of these stars are hot enough to ionise the nebula.

Avedisova places the Rosette nebula in star formation region SFR 206.30-2.11 with 114 components, including 6 masers, 34 infrared sources and the radio source W16.

Near by the Rosette molecular cloud are two smaller clouds associated with the HII regions Sh 2-280 and Sh 2-282.

You can find out more about this region in the Mon OB2 section of the description of the Fox Fur and Rosette (210° - 200°) sector in the Commentary on the Galactic Plane.

An astonishing image that shows the entire Monoceros region in one image (including the Fox Fur nebula) can be found here.

Sh 2-276

Coordinates: (206.71°, -20.46°)
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Barnard's Loop is a ring of ionised gas that appears to surround the Flame (Sh 2-277) and Orion (Sh 2-281) nebulae and is the brightest portion of the much larger Orion-Eridanus superbubble. Many researchers assume that Barnard's Loop is physically associated with these nebulae and the Orion molecular clouds. However, a 2005 study argues that Barnard's Loop is considerably closer than the gas that makes up the main portion of the Orion molecular clouds.

This image shows only a small portion of the nebula. You can see the full Loop here.

Sh 2-277

Coordinates: (206.91°, -16.83°)
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This is the Flame nebula, also known as the radio source W 12 and contained within the molecular cloud Orion B. It is associated with the star cluster NGC 2024 and is largely ionised by the obscured O8-O9.7 star 2MASS J05414580-0154297. It can be seen in a similar direction as the O9.5Ib multiple supergiant Alnitak (Zeta Orionis), one of the three prominent hot young stars in Orion's belt.

You can see a spectacular view of the Flame nebula and the nearby Horsehead nebula in this image.

Sh 2-278

Coordinates: (207.38°, -22.94°)
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This is the high latitude cloud MBM 110. Avedisova places it in star formation region SFR 206.70-20.5 along with the dark nebula LDN 1634 and the reflection nebula NGC 1788.

You can view a beautiful image of this nebula here.

Sh 2-279

Coordinates: (208.45°, -19.09°)
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Located near in the sky to the Orion nebula, Sh 2-279 is often called the Running Man nebula and is a combination of a reflection nebula and an HII region. Sharpless says that this nebula is ionised by the B3 star HD 37018 (42 Orionis). (SIMBAD gives a hotter B1 V class.) Kharchenko places this star in the star cluster NGC 1977. A 1977 paper agrees that HD 37018 ionises Sh 2-279, and adds that Sh 2-279 is an HII region that includes the star clusters NGC 1973, NGC 1975 and NGC 1977. (SIMBAD identifies these objects as "bright nebula" rather than star clusters.)

Avedisova places Sh 2-279 in star formation region SFR 210.76-19.61 with a number of better known objects, including the nebula IC 430, the HII regions M 43 and NGC 1999, the star clusters NGC 1977 and NGC 1980 and the dark nebula LDN 1647.

You can view a beautiful image of this nebula here.

Sh 2-280

Coordinates: (208.73°, -2.65°)
[ See details ]

The HII region Sh 2-280 appears to be located near or at the edge of the Rosette molecular cloud. Avedisova suggests two possible ionising stars, the O7 HD 46573 and the B0 III giant HD 46847. A 1981 paper also states that the ionising star for this HII region is HD 46573. HD 46573 may be an outlying star of the NGC 2244 cluster, which ionises Sh 275, the Rosette nebula.

You can view good images of Sh 2-280 on Dean Salman's site here.

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Stewart Sharpless published the second and final version of his famous nebula catalog in 1959. Although astronomers publish articles referring to the Sharpless nebulae almost every month, there seems to be few places on the Internet that bring together information on these nebulae as a whole - unlike, for example, the Messier catalog. This is most likely because the Messier objects are visible to anyone with a pair of binoculars or a small telescope. Most of the Sharpless objects are clearly visible only in CCD images or in photographic plates taken by large telescopes. Fortunately some of these plates have now been digitally scanned and made publicly available.

Many of the brightest and most beautiful Milky Way star formation regions visible from the northern hemisphere are in the Sharpless catalog so the 313 objects it contains are well worth examining carefully. (In fact there are more than 313 objects as subsequent research has shown that some of the Sharpless nebulae consist of more than one object.) Although the Sharpless catalog is only intended to be complete for objects visible north of declination -27 degrees, a similar catalog covering the southern hemisphere was published by Alex Rodgers, Colin Campbell, and John Whiteoak in 1960, which is largely an expansion of Colin Gum's earlier catalog. You can visit a gallery of these RCW nebulae here. At least 50 objects in the Sharpless catalog are also in the RCW catalog and I have noted this in the descriptions of these objects.

Most of the images used to illustrate the Sharpless catalog were created using the POSS-II/UKSTU data of the Digitized Sky Survey, or, where available, the more detailed SuperCOSMOS Sky Survey. In both cases, green = UKST Infrared. Because green represents infrared, the images are not quite the same as would be seen at purely visual frequencies. Green in these images usually reveals warm dust or red giant stars.

These images were created using the POSS-II/UKSTU data of the Digitized Sky Survey and SuperCOSMOS using the process described here.

According to my correspondence with the Royal Observatory Edinburgh and the Space Telescope Science Institute, I am allowed to use the POSS-II/UKSTU data to create and display images for non-commercial purposes so long as I include this fine print for the SuperCOSMOS data:

Use of these images is courtesy of the UK Schmidt Telescope (copyright in which is owned by the Particle Physics and Astronomy Research Council of the UK and the Anglo-Australian Telescope Board) and the Southern Sky Survey as created by the SuperCOSMOS measuring machine and are reproduced here with permission from the Royal Observatory Edinburgh.

and this acknowledgement taken from the DSS site:

The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.

The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation.

The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together known as the SERC-J), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken with the UK Schmidt.

The "Second Epoch Survey" of the southern sky was made by the Anglo-Australian Observatory (AAO) with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright © 1993-5 by the Anglo-Australian Observatory Board, and are distributed herein by agreement.

The "Equatorial Red Atlas" of the southern sky was made with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright © 1992-5, jointly by the UK SERC/PPARC (Particle Physics and Astronomy Research Council, formerly Science and Engineering Research Council) and the Anglo-Australian Telescope Board, and are distributed herein by agreement.

The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright © 1993-1995 by the California Institute of Technology and are distributed herein by agreement. The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright © 1993-1995 by the California Institute of Technology and are distributed herein by agreement.