The Sharpless Catalog
Click on the small images to see larger ones.
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The available distance estimates place Sh 2-291 in the Cygnus (Outer) arm.
No ionising star appears to have been identified in the scientific literature.
Dean Salman has imaged Sh 2-291 together with the nearby BFS 63 in this image.
Sh 2-292
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Avedisova places this nebula in star formation region SFR 224.20-1.60 with other parts of the Seagull nebula.
You can find good images of both the head and the wings of the Seagull nebula here and here and read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane
Sh 2-293
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According to Avedisova, Sh 2-293 is ionised by the B2 III giant HD 52721. SIMBAD gives a slightly different B2Vne class for this star and identifies it as the illuminating source for the reflection nebula VDB 88, implying that Sh 2-293 may be both an HII region and reflection nebula.
Avedisova places it in star formation region SFR 224.20-1.60 with other parts of the Seagull nebula. However, in a 1989 study she places Sh 2-293 at a distance of about 750 parsecs, which is considerably closer than the other parts of the Seagull nebula, implying that it may be a foreground object.
You can read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane.
You can see a labeled diagram of parts of the Seagull nebula region (including Sh 2-293) at the bottom left of this page.
You can see Sh 2-293 and Sh 2-295 together in this image by astrophotographer Dean Salman.
Sh 2-294
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Its odd shape looks like an upside down octopus - should it perhaps be called the Octopus nebula?
Sh 2-295
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SIMBAD lists HD 52942 as the illuminating star for the reflection nebula VDB 90a and BD -11 1761 as the illuminating star for the reflection nebula VDB 92b, implying that the HII region surrounds several reflection nebulae.
You can read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane.
You can see a labeled diagram of parts of the Seagull nebula region (including Sh 2-293) at the bottom left of this page.
You can see Sh 2-293 and Sh 2-295 together in this image by astrophotographer Dean Salman.
Sh 2-296
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Avedisova lists 4 ionising stars for Sh 2-296, including 3 B-class stars and the O6.5V star HD 54662. (SIMBAD gives an O7III class for this star.) She places it in star formation region SFR 224.20-1.60 with other parts of the Seagull nebula.
You can find good images of both the head and the wings of the Seagull nebula here and here and read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane.
Sh 2-297
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Avedisova lists 5 possible ionising stars, including the O7.5 V star HD 53975, the O9.5 V star HD 54879 and the B1 II/III star HD 53623. (SIMBAD gives the class of HD 53975 as B7, too cool to be an ionising star. SIMBAD may be incorrect, however.) She places Sh 2-297 in star formation region SFR 224.20-1.60 with other parts of the Seagull nebula.
You can find good images of both the head and the wings of the Seagull nebula here and here and read a detailed commentary on the Seagull (230° - 220°) sector, which is part of the Commentary on the Galactic Plane.
You can see more of the surrounding nebulosity in this image by Dean Salman and more detail in the nebula itself in this image by Adam Block.
Sh 2-298
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Sh 2-299
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A 1995 paper places Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 into the same giant molecular cloud complex. A 1996 paper places Sh 2-305 to Sh 2-309 into molecular cloud [JKK96] D within the enormous infrared ring called the GS234-02 supershell, in the Perseus arm.
You can view the enormous dust ring around the supershell in this WISE infrared image. Sh 2-299 and Sh 2-300 also appear in this direction.
Sh 2-300
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A 1995 paper places Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 into the same giant molecular cloud complex. A 1996 paper places Sh 2-305 to Sh 2-309 into molecular cloud [JKK96] D within the enormous infrared ring called the GS234-02 supershell, within the Perseus arm.
You can view the enormous dust ring around the supershell in this WISE infrared image. Sh 2-299 and Sh 2-300 also appear in this direction.
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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.