|Observation data (J2000 epoch)|
|Right ascension||03h 46m 48.5s|
|Declination||+68° 05′ 46″|
|Redshift||31 ± 3 km/s|
|Distance||10.7 ± 0.9 Mly (3.3 ± 0.3 Mpc)|
|Apparent dimensions (V)||21′.4 × 20′.9|
|Apparent magnitude (V)||9.1|
|UGC 2847, PGC 13826, Caldwell 5|
IC 342 (IC=Index Catalogue)(also known as Caldwell 5) is an intermediate spiral galaxy in the constellation Camelopardalis. The galaxy is near the galactic equator where dust obscuration makes it a difficult object for both amateur and professional astronomers to observe, though it can readily be detected even with binoculars. The dust of the Milky Way makes it difficult to determine the precise distance; modern estimates range from about 7 Mly to about 11 Mly.
The galaxy is one of the brightest two galaxies in the IC 342/Maffei Group of galaxies, one of the galaxy groups that is closest to the Local Group. The galaxy was discovered by William Frederick Denning in 1895. Edwin Hubble first thought it to be in the Local Group, but later it was demonstrated that the galaxy is outside the Local Group.
In 1935, Harlow Shapley declared that this galaxy was the third largest spiral galaxy by angular size then known, smaller only than the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33), being wider that the full moon. (Modern estimates are more conservative, giving the apparent size as one-half to two-thirds the diameter of the full moon).
It has an H II nucleus.
- "NASA/IPAC Extragalactic Database". Results for IC 342. Retrieved 2006-11-01.
- I. D. Karachentsev; V. E. Karachentseva; W. K. Hutchmeier; D. I. Makarov (2004). "A Catalog of Neighboring Galaxies". Astronomical Journal 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
- Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics 49 (1): 3–18. Bibcode:2006Ap.....49....3K. doi:10.1007/s10511-006-0002-6.
- O'Meara, Stephen James (2002). The Caldwell Objects. Cambridge University Press. pp. 30–32. ISBN 0-933346-97-2.
- "Hidden Galaxy IC 342". Astronomy Picture of the Day. NASA. 22 December 2010. Retrieved 28 January 2013.
- SEDS IC 342. Archived January 2, 2007, at the Wayback Machine.
- Border Cities Star (Windsor, Ontario), "Spiral Galaxy Third Biggest", 24 June 1935, p.8
- Ho, Luis C.; Filippenko, Alexei V.; Sargent, Wallace L. W. (1997). "A Search for 'Dwarf' Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies". Astrophysical Journal Supplement 112: 315. arXiv:astro-ph/9704107. Bibcode:1997ApJS..112..315H. doi:10.1086/313041.
- NASA Astronomy Picture of the Day – 22 December 2010
- IC 342 (image included)
- IC 342 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images