The Sharpless Catalog

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Sh 2-111

Coordinates: (81.18°, -17.02°)
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Sh 2-111 can be seen clearly in this false colour hydrogen-alpha image as one of the brightest parts of a ridge of faint clouds below the Cygnus X region.

There seems to be no significant references to this nebula in the scientific literature.

Sh 2-112

Coordinates: (83.78°, 3.28°)
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The ionising star for this nebula is the O8V class multiple BD+45 3216 (SAO 49801).

You can view an IPHAS image of this object here. Sh 2-112 is prominent in infrared as can be seen in this MSX image.

Sh 2-113

Coordinates: (83.95°, -8.03°)
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Sh 2-113 and Sh 2-114 form, respectively, the southern and northern portions of a filamentary circle that resembles a supernova remnant. However, no supernova remnant appears to be recorded for this location.

Examining this region in hydrogen-alpha suggests that these nebulae are joined to the equally mysterious Sh 2-118 and Sh 2-123 in a long ridge of nebulosity south and south-east of Sh 2-117, the North American nebula. Sh 2-113, Sh 2-118 and Sh 2-123 have distance estimates of about 4000 parsecs. If this ridge is also at 4000 parsecs, it must be enormous.

This identical structure can be seen in more detail at the bottom left of this radio and far infrared image of the Cygnus region.

You can view an image of both Sh 2-113 and Sh 2-114 together at the bottom of this page.

Sh 2-114

Coordinates: (84.2°, -7.88°)
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Sh 2-113 and Sh 2-114 form, respectively, the southern and northern portions of a filamentary circle that resembles a supernova remnant. However, no supernova remnant appears to be recorded for this location.

Examining this region in hydrogen-alpha suggests that these nebulae are joined to the equally mysterious Sh 2-118 and Sh 2-123 in a long ridge of nebulosity south and south-east of Sh 2-117, the North American nebula. Sh 2-113, Sh 2-118 and Sh 2-123 have distance estimates of about 4000 parsecs. If this ridge is also at 4000 parsecs, it must be enormous.

This identical structure can be seen in more detail at the bottom left of this radio and far infrared image of the Cygnus region.

You can view a very good optical image of Sh 2-114 here.

Sh 2-115

Coordinates: (84.83°, 3.91°)
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This HII region lies in the same direction as the radio source W71 and is ionised by the O6 Ib supergiant LS III +46 12 which is part of the star cluster Berkeley 90. The cloud surrounding Berkeley 90 (part of which is visible as Sh 2-115) contains 4400 solar masses of gas and dust and is about 30 pc long.

Infrared observations reveal a large, complex structure with multiple bubbles as can be seen in this MSX image. The nebula is also prominent at radio frequencies.

Sh 2-116

Coordinates: (85.0°, 4.5°)
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Often described as the planetary nebula Abell 71, but a 1991 study by Paris Pismis and colleagues concluded that this object is actually an HII region.

Curiously, Pismis' study appears to have been overlooked by other professional astronomers as Abell 71 continues to appear in lists of planetary nebula.

The green glow next to it is probably a fault in the infrared photographic plate.

Sh 2-117

Coordinates: (85.49°, -1.0°)
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Sh 2-117 is composed of the North American and Pelican nebulae, NGC 7000/IC 5070/IC 5067, which are visible through gaps in the Rift system of dusty giant molecular clouds that separates the Gould Belt from the Cygnus X complex.

Sh 2-117 appears to be ionised by the O5V star 2MASS J20555125+4352246. This star is heavily obscured by the dust in the Lynds dark nebula LDN 935, a Rift cloud which lies at a distance of about 520 parsecs in front of Sh 2-117, and appears to divide the North American and Pelican nebulae.

The radio source W80 appears in this direction. A 2009 paper concludes that W80 is generated only partly by Sh 2-117 and includes emission from 4 distinct sources located at different distances along the line of sight.

Only a small part of this large and relatively close region appears in this image. You can see a better image of this huge nebula here.

Sh 2-118

Coordinates: (87.49°, -8.92°)
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Sh 2-118 is one of the largest nebulae in apparent size in the Sharpless catalog, but essentially nothing about it has been published in the scientific literature.

Examining this region in hydrogen-alpha suggests that Sh 2-118 is joined to the equally mysterious Sh 2-113, Sh 2-114 and Sh 2-123 in a long ridge of nebulosity south and south-east of Sh 2-117, the North American nebula. Sh 2-114, Sh 2-118 and Sh 2-123 have distance estimates of about 4000 parsecs. If this ridge is also at 4000 parsecs, it must be enormous.

Sh 2-119

Coordinates: (87.6°, -3.86°)
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Sh 2-119 is located near the North American nebula (Sh 2-117, NGC 7000). Avedisova lists 6 ionising stars. The hottest of these is the O 7.5 III runaway star 68 Cygni (HD 203064), which was likely blasted out of the Cepheus OB2 association about 5.2 million years ago.

It is also known as HS 240 = [GS55] 240. Good colour images of this nebula can be found here and here.

Sh 2-120

Coordinates: (90.22°, 2.04°)
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A radio map of Sh 2-120 shows a shell-like structure around a central source. Very little information is available in the literature apart from this map.

According to a 1978 study, Sh 2-120, Sh 2-121, Sh 2-127 and Sh 2-128 are all at about the same distance of 7500 parsecs and are "probably distant HII regions associated with a spiral feature more distant than the Perseus arm".

Sh 2-120 appears behind the much closer dark nebula LDN 988, which has been informally called the Pincushion cloud.

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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.