Crescent Nebula

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title: "Crescent Nebula" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["ngc-objects", "wolf–rayet-nebulae", "cygnus-(constellation)", "sharpless-objects", "caldwell-objects", "astronomical-objects-discovered-in-1792"] description: "Emission nebula in the constellation Cygnus" topic_path: "general/ngc-objects" source: "https://en.wikipedia.org/wiki/Crescent_Nebula" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Emission nebula in the constellation Cygnus ::

::data[format=table title="Infobox nebula"]

Field	Value
name	Crescent Nebula
image	NGC 6888.png
caption	The Crescent Nebula, captured with a color camera, narrowband filter, and high-speed amateur telescope
type	Emission
epoch	J2000.0
ra	{{cite simbad
title	NGC 6888
access-date	2007-04-23}}
dec
dist_ly	5,000
appmag_v	+7.4
size_v	18′ × 12′
constellation	Cygnus
names	NGC 6888, Sharpless 105, Caldwell 27
::

| name = Crescent Nebula | image = NGC 6888.png | caption = The Crescent Nebula, captured with a color camera, narrowband filter, and high-speed amateur telescope | type = Emission | epoch = J2000.0 | ra = {{cite simbad | title=NGC 6888 | access-date=2007-04-23}} | dec = | dist_ly = 5,000 | appmag_v = +7.4 | size_v = 18′ × 12′ | constellation = Cygnus | radius_ly = | absmag_v = | notes = | names = NGC 6888, Sharpless 105, Caldwell 27 The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by William Herschel in 1792. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray-emitting temperatures.

Visibility

The Crescent Nebula is a rather small object located about 2 degrees Southwest of Sadr. While considered bright by astronomical imaging standards, visually it is relatively faint. For most telescopes it requires a UHC or OIII filter to see. Under favorable circumstances a telescope as small as 8 cm (with filter) can see its nebulosity. With higher magnification, it has been reported to have a resemblance to a Euro sign shape leading to a nickname the "Euro Sign Nebula."

Gallery

File:NGC 6888 HOO By Don Christopher Deaver.jpg|alt=Crescent Nebula NGC 68888 Imaged by Don Christopher Deaver|NGC 6888 in Hydrogen and Oxygen Light. HOO Palette. Imaged by Don Christopher Deaver File:Crescent Nebula, Hydrogen alpha and Oxygen III by Stephan Hamel.jpg|Crescent Nebula in H-alpha and OIII. Imaged with a 715mm focal length telescope. The hydrogen gas is red. The oxygen is blue. File:Crescent Nebula in H-alpha.jpg|Image of NGC 6888 using H-alpha filter. File:NGC 6888 (Crescent Nebula) bicolor.jpg|Picture of NGC 6888 captured in narrowband by amateur astronomer Luca Moretti File:NGC 6888, the Crescent Nebula in Cygnus, imaged by amateur astronomer Patrick Hsieh.jpg|NGC 6888 imaged in 3 nm hydrogen-alpha and oxygen-III narrowband at 2800mm focal length by amateur astronomer Patrick Hsieh. File:C27 - Crescent Nebula.jpg|Crescent Nebula (Caldwell27) was captured by David Rousseau from an urban location in Québec, Canada, using Ha and OIII narrowband filters. File:CrescentBicolorHunterWilson.jpg|The Crescent Nebula, as taken by an amateur astronomer File:Ngc6888-hoo-bright.png|NGC 6888 - The Crescent Nebula, wide field in HOO.

References

References

1. "NGC 6888". The NGC/IC Project.
2. "hubble-watches-star-tear-apart-its-neighborhood".
3. "Crescent Nebula".

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::