Galactic Nebula NGC 7822

History

This nebula was discovered by John Herschel on 16 November 1829 using his 18.3 inch reflector. He cataloged it as h 2302 (GC 5051) and described it with the words: «The central part of what I am positive is an enormously large but extremely faint nebula of a round figure, though I cannot trace its limits. The night exquisite. I swept often across it to be sure, but always recurred to the same place. No doubt but can never be seen but in the best state of the air and sky. Diameter 10' ±.» [277, 466] The discovery was later added as NGC 7822 by Dreyer. [313]

NGC 7822, Cederblad 214
NGC 7822, Cederblad 214: Emission nebula in Cepheus; Celestron RASA 11" f/2.22; ZWO ASI6200 Pro; Tentlingen; © 2020 Peter Kocher
NGC 7822
NGC 7822: Emission nebula in Cepheus; 500 mm Cassegrain 5800 mm f/11.4; SBIG STL11K; 120+40+40+40 min LRGB; Bernese Highlands; © 2011 Radek Chromik

Physical Properties

The nebula is an approximately 3° large, complex emission nebula full of young, hot stars, which heat up the gas with their strong ultraviolet radiation, ionize it and thus cause it to glow. A few wisps of dark dust partially obscure the glowing nebula. At an estimated distance of around 3000 light-years, this gas nebula measures around 150 light-years in diameter. The loose star cluster at its center contains about 40 O and B stars, of which spectral type O7 is the youngest and hottest. The estimated age is about five to six million years. [145, 196]

NGC 7822
NGC 7822: In visible light (DSS) and infrared (WISE). Modified sections from CDS Aladin Lite [147]

Fig. 1 shows a section of the southern part of the nebula, also known as Cederblad 214 or LBN 581. The arcuate, fainter northern part is also designated LBN 589. The entire nebula complex is also known as Sharpless 171 (Sh2-171). Some atlases refer to the entire nebula complex as NGC 7822, others only to the northern part. In Fig. 2 one sees the whole nebula alternately in the visible light and in the infrared. The infrared light penetrates the dark clouds and some new nebula structures and stars become visible.

Revised+Historic NGC/IC, Version 22/9, © Dr. Wolfgang Steinicke [277]
DesignationNGC 7822
TypeEN
Right Ascension00h 03m 36.0s
Declination+67° 09' 00"
Diameter100 arcmin
Metric Distance0.900 kpc
Dreyer Description! eeF, eeL
Identification, RemarksLBN 583, CED 214A, in Sh2-171

Finder Chart

NGC 7822 is located in the eastern part of the constellation Cepheus between the «gable» of «the crooked house of King Cepheus» and the «W» the Cassiopeia. In Central Europe, the nebula is circumpolar and is highest in the night sky from May to December.

Chart Galactic Nebula NGC 7822
Galactic Nebula NGC 7822 in constellation Cepheus. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

More Objects Nearby (±15°)

References

145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
147Aladin Lite; aladin.u-strasbg.fr/AladinLite (2020-12-23)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
313«A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged» Dreyer, J. L. E. (1888); Memoirs of the Royal Astronomical Society. 49: 1–237; Bibcode:1888MmRAS..49....1D
466«Observations of nebulæ and clusters of stars, made at Slough, with a twenty-feet reflector, between the years 1825 and 1833» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1833, Pages: 359-505; DOI:10.1098/rstl.1833.0021