| Emission nebula | |
|---|---|
 Sh2-201 | |
| Observation data: epoch | |
| Right ascension | 2h 59m |
| Declination | 60d 16m |
| Distance | 9980 ly (3060 pc) |
| Apparent dimensions (V) | 5' x 5' |
| Constellation | Cassiopeia |
Sh2-201 is an emission nebula in the Cassiopeia constellation. It is in the eastern part of the constellation along the eastern border of the IC 1848. The nebula is 9980 light-years away from Earth. It is also seen close to Sh2-199. [1]
NGC 281, IC 11 or Sh2-184 is a bright emission nebula and part of an H II region in the northern constellation of Cassiopeia and is part of the Milky Way's Perseus Spiral Arm. This 20×30 arcmin sized nebulosity is also associated with open cluster IC 1590, several Bok globules and the multiple star, B 1. It collectively forms Sh2-184, spanning over a larger area of 40 arcmin. A recent distance from radio parallaxes of water masers at 22 GHz made during 2014 is estimated it lies 2.82±0.20 kpc. from us. Colloquially, NGC 281 is also known as the Pacman Nebula for its resemblance to the video game character.
Open Cluster NGC 2175 is an open cluster in the Orion constellation, embedded in a diffusion nebula. It was discovered by Giovanni Batista Hodierna before 1654 and independently discovered by Karl Christian Bruhns in 1857. NGC 2175 is at a distance of about 6,350 light years away from Earth.
The Medusa Nebula is a planetary nebula in the constellation of Gemini. It is also known as Abell 21 and Sharpless 2-274. It was originally discovered in 1955 by University of California, Los Angeles astronomer George O. Abell, who classified it as an old planetary nebula. Until the early 1970s, the nebula was thought to be a supernova remnant. With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula. As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported.
NGC 1555, sometimes known as Hind's Variable Nebula, is a variable nebula, illuminated by the star T Tauri, located in the constellation Taurus. It is also in the second Sharpless catalog as 238. It is a Herbig–Haro object. The nebula was discovered on October 11, 1852, by John Russell Hind.
The Sharpless catalog is a list of 313 H II regions intended to be comprehensive north of declination −27°. The first edition was published in 1953 with 142 objects (Sh1), and the second and final version was published by US astronomer Stewart Sharpless in 1959 with 312 objects. Sharpless also includes some planetary nebulae and supernova remnants, in addition to H II regions.
The Heart Nebula is an emission nebula, 7500 light years away from Earth and located in the Perseus Arm of the Galaxy in the constellation Cassiopeia. It was discovered by William Herschel on 3 November 1787. It displays glowing ionized hydrogen gas and darker dust lanes.
Westerhout 5 is an emission nebula located in Cassiopeia. Several small open clusters are embedded in the nebula: CR 34, 632, and 634 and IC 1848. The object is more commonly called by the cluster designation IC 1848.
Sh2-155 is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. It is widely known as the Cave Nebula, though that name was applied earlier to Ced 201, a different nebula in Cepheus. Sh2-155 is an ionized H II region with ongoing star formation activity, at an estimated distance of 725 parsecs from Earth.
Sharpless 101 (Sh2-101) is a H II region emission nebula located in the constellation Cygnus. It is sometimes also called the Tulip Nebula because it appears to resemble the outline of a tulip when imaged photographically. It was catalogued by astronomer Stewart Sharpless in his 1959 catalog of nebulae. It lies at a distance of about 6,000 light-years (5.7×1016 km; 3.5×1016 mi) from Earth.
NGC 1931 is an emission and reflection nebula in the constellation Auriga. The nebula has been referred to as a "miniature version of the Orion Nebula", as it shares some of the same characteristics. It is a mixed emission-reflection nebula, and contains a smaller version of the Trapezium in its hot young star cluster centered in the emission nebula. The entire cluster/nebula complex is only about 3 arcmin in size. The distance from earth is estimated at about 7000 light years.
Sh 2-1, also known as Sharpless 1, is a reflection nebula in the constellation of Scorpius with Pi Scorpii at its center. It appears as a modest brightness making it one of the easier Sharpless catalog objects to view. It features an apparent central star inside the nebulosity however it is not part its system nor a left over remnant.
Sh 2-2, also known as Sharpless 2, is an emission nebula in the constellation of Scorpius. It appears as a mid-range brightness making it difficult to view. It is believed to currently host an X-ray binary star that originated and was ejected from the Scorpius OB1 association. Amateur astronomers can usually see it with a wide field telescope and a hydrogen-alpha filter.
The Ghost Nebula is a reflection nebula located in the constellation Cepheus.
Sharpless 2-88 or Sh 2-88 is a region including the diffuse nebula Sh 2-88A and the two compact knots Sh 2-88B1 and Sh 2-88B2, all of which are associated with Vulpecula OB1.
Sh2-297 is an emission nebula in the constellation Canis Major. The region was catalogued in 1959 in the extended seconded edition of the Sharpless catalogue. This area is part of the Canis Major OB1 Association, and is a very active area of new star formation.
NGC 1624, also known as Sh2-212 in the Sharpless catalog, is a very young open cluster in the constellation Perseus inside an emission nebula. It was discovered by German-British astronomer William Herschel in 1790. NGC 1624 is about 20,000 ly from Earth, and latest estimates give it an age of less than 4 million years. Its apparent magnitude is 11.8, and apparent diameter is about 3.0 arc minutes. Its celestial location is right ascension (α) 04h 40m 36.0s and declination (δ) +50° 27′ 42″. It is potentially an area of massive star formation.
Sh2-7 is an emission nebula in the Scorpius constellation. The nebula is around the star Delta Scorpii. It lies next to a large reflection nebula, Sh2-1.
Sh2-9, also known as Gum 65, is combination emission and reflection nebula in the Scorpius constellation, surrounding the multiple star system Sigma Scorpii. Sigma Scorpii is 1° to the northwest of Messier 4, and the nebula can be easily seen with small telescopes.
Sh2-10, also called RCW 130, is an emission nebula in the Scorpius constellation.
Sh2-113 also known as the flying dragon nebula or LBN 333, is a small planetary nebula that resembles a supernova remnant (SNR) but with no evidence to support it being an SNR. Sh2-113 is located in the northern hemisphere constellation of Cygnus south of the star Deneb. Nearby are other planetary nebulas named K 2-81, Sh2-114, Kn 26 and LBN 346.
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