The Sharpless Catalog

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Sh 2-261

Coordinates: (194.1°, -1.9°)
[ See details ]

Lower's nebula is an HII region ionised by the O7.5V runaway star HD 41997.

Sh 2-262

Coordinates: (194.61°, -19.95°)
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Another little-studied nebula in the direction of the Orion-Eridanus superbubble. BFS detect no CO emission in this direction. A 2005 paper comments that Sh 2-262 is most likely associated with the Lambda Orionis ring (Sh 2-264), and indeed, it can be seen in this Milky Way Explorer image as an hydrogen-alpha ridge visible below Sh 2-264.

Dean Salman has created a detailed image of this nebula.

Sh 2-263

Coordinates: (194.65°, -15.62°)
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This HII region and reflection nebula is ionised by the B0-B1 V star HD 34989. Avedisova places it in star formation region SFR 195.06-11.99 as part of the Lambda Orionis ring complex along with Sh 2-264, Sh 2-265 and the dark nebula LDN 1582 (Barnard 32).

Dean Salman has created a detailed image of this nebula.

Sh 2-264

Coordinates: (195.07°, -11.97°)
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The combined HII region and supernova remnant Sh 2-264 is called the Angelfish nebula because of its appearance in visual light, or the Lambda Orionis ring because of its appearance in infrared. It is ionised by the O8 III subgiant star Lambda Orionis, and to a lesser extent, the 11 B stars near to it, which together form the loose star association Collinder 69, often called the Lam Ori cluster.

The region around Lambda Orionis is dominated by a ring of molecular clouds whose structure can perhaps best be explained by a supernova very close to the star about 1 million years ago. The image shows only a small fragment of Sh 2-264.

This object is impressive at visual frequencies and astonishing in infrared, which shows the true extent of the ring of molecular clouds surrounding the HII region.

Sh 2-265

Coordinates: (195.1°, -16.8°)
[ See details ]

This diffuse HII region is part of the Barnard 223 dark cloud in the southern part of the Lambda Orionis ring (most of which forms the huge Sh 2-264 HII region). However, Sh 2-265 is not ionised by Lambda Orionis itself. Instead it is probably ionised by stars in the Ori OB1b portion of the Ori OB1 association.

Avedisova places it in star formation region SFR 195.06-11.99 as part of the Lambda Orionis ring complex along with Sh 2-263, Sh 2-264 and the dark nebula LDN 1582 (Barnard 32).

The position of this nebula in the BFS Vizier catalog is currently incorrect.

Sh 2-266

Coordinates: (195.66°, -0.08°)
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Sh 2-266 is a peculiar object consisting of a cometary nebula surrounding the Be class supergiant MWC 137, which may be generating a strong stellar wind and appears to be surrounded by a small star cluster. It appears to be located in the Cygnus (outer) arm.

Sh 2-267

Coordinates: (196.2°, -1.2°)
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This HII region (sometimes incorrectly identified as a planetary nebula) is ionised by the O9 V class star MFJ SH 2-267 2 and contains the infrared cluster [BDS 2003] 81.

Sh 2-268

Coordinates: (196.38°, -2.85°)
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This large but faint nebula is prominent in hydrogen-alpha and infrared. According to Avedisova, it is ionised by the B1 III giant HD 42352.

The position of this nebula in the BFS Vizier catalog and in SIMBAD is currently incorrect.

For more information on this region, including detailed references, see the Sh 2-266 to Sh 2-272 section of the description of the Orion (200° - 190°) sector in the Commentary on the Galactic Plane.

Sh 2-269

Coordinates: (196.4°, -1.7°)
[ See details ]

Sh 2-269 lies in front of a 8700 solar mass giant molecular cloud in the Cygnus (outer) arm. It is bisected by a dust lane and is ionised by two stars in the western side of the nebula. One is a B0.5 V star (MFJ Sh 2-269 2), the other is visible only in the infrared and appears to be either O8 or O9.5.

Sh 2-270

Coordinates: (196.84°, -3.11°)
[ See details ]

This bipolar nebula contains an infrared star cluster (IRAS 06073+1249) embedded in a 1000 solar mass molecular cloud and may be ionised by a B0.5 V class star. There are a wide range of distance estimates available for this object. Some estimates place it in the Perseus arm, and others closer to the Outer arm.

For more information on this region, including detailed references, see the Sh 2-266 to Sh 2-272 section of the description of the Orion (200° - 190°) sector of the Commentary on the Galactic Plane.

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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.