The Sharpless Catalog

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Sh 2-71

Coordinates: (36.1°, -1.4°)
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This is an unusual planetary nebula that appears to have a binary central star. The central star is variable with a period of 68 days and appears to be embedded in a dense core nebula.

Sh 2-72

Coordinates: (36.4°, -1.7°)
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This relatively large HII region might be ionised by the B0.5 IV star BD +2 3762 according to Forbes, but this is uncertain.

This nebula is prominent at radio frequencies as can be seen in this Effelsberg image and this VLA image and lies at the centre of a faint infrared ring as can be seen in MSX.

You can find a good visual frequency image here.

Sh 2-73

Coordinates: (37.69°, 44.55°)
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This local molecular cloud is also known as LBN 105, MBM 40 and IREC 53. MBM 40 contains 20 to 40 solar masses of gas. There are no signs of star formation. Like several other local molecular clouds, MBM 40 has a pronounced hairpin shape.

Sh 2-74

Coordinates: (39.9°, -1.3°)
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This nebula is ionised by the O9V class Sherwood 182 ([F89b] S74 1). It is either at the same distance as the powerful radio source W 50, or sits in front of it, depending upon the authority.

Both W 50 and Sh 2-74 can be seen in this radio image. This image suggests that W 50 is a distinct object but might be joined to Sh 2-74 by a spur visible at radio frequencies.

The microquasar SS 433 is part of W 50. This bizarre object, also called V1343 Aquilae, is spewing out two jets of material at more than one-quarter the speed of light.

Sh 2-75

Coordinates: (40.14°, 1.51°)
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There is very little to report about this faint, obscured nebula located above the galactic plane except that ammonia was detected in this direction in a 1996 study and it is prominent in infrared as can be seen in this MSX image.

Sh 2-76 and several other prominent infrared sources are also located in a similar direction suggesting that there is something interesting in this region but there is little in the scientific literature about it. It is also significant that millimetre emission suggests the presence of dense molecular clouds in this direction. In this poster, the region is labeled "Aquila Rift".

Sh 2-76

Coordinates: (40.5°, 2.5°)
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This nebula, located well above the galactic plane in the direction of the Aquila Rift dust clouds, is dim at visual frequencies but appears as a large bright bubble in infrared, as can be seen in this MSX image, and is also prominent at radio frequencies.

The nebula lies in the same approximate direction as the radio source W45, but Westerhout noted that the identification of this radio source with Sh 2-76 was "probably incorrect".

On the other hand, Avedisova includes W45 and Sh 2-76 together in star formation region SFR 40.44+2.45 along with 5 masers and several other HII regions visible in infrared.

Sh 2-77

Coordinates: (40.55°, -12.08°)
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This appears to be ths same as the high velocity cloud [PDS2002] HIPASS HVC 378 = [DBB2002] 106.

Sh 2-78

Coordinates: (46.84°, 3.84°)
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This is the old planetary nebula CTSS 3 and lies at a distance of 700 parsecs.

Sh 2-79

Coordinates: (48.96°, -0.55°)
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The very faint nebula in the image may be ionised by the B 2.5V class star [F89b] S79 1. Other sources state that at least some of the visual emission in this direction may be associated with the supernova remnant SNR G49.2-0.7 (also called W51C) which is believed to be at a distance of 6 kpc.

Avedisova combines Sh 2-79 and W51C in the star formation region SFR 48.96-0.55 along with four infrared sources.

Sh 2-80

Coordinates: (50.2°, 3.3°)
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This is a ring nebula surrounding the runaway Wolf Rayet star WR 124, also known as Merrill's star.

You can see this nebula in much greater detail in this Hubble image.

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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.