Medusa Nebula

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Medusa Nebula
Medusa nebula.jpg
Medusa nebula, 24 inch telescope on Mt. Lemmon, AZ.
Observation data: J2000.0 epoch
Right ascension 07h 29m 02.69s[1][2]
Declination+13° 14′ 48.4″[1][2]
Distance1,500 ly (460 pc)[3] ly
Apparent magnitude (V)15.99[1]
Apparent dimensions (V)4 ly[3]
Physical characteristics
Absolute magnitude (V)7.68
Notable featuresVery large & very low surface brightness
DesignationsSharpless 2-274, PK 205+14 1, Abel 21 [1]
See also: Lists of nebulae

Coordinates: Sky map 07h 29m 02s, +13° 14′ 15″

The Medusa Nebula is a large planetary nebula in the constellation of Gemini on the Canis Minor border. It is also known as Abell 21 and Sharpless 2-274. It was originally discovered in 1955 by UCLA astronomer George O. Abell, who classified it as an old planetary nebula.[4] The braided serpentine filaments of glowing gas suggests the serpent hair of Medusa found in ancient Greek mythology.

Until the early 1970s, the Medusa 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.[4]

As the nebula is so big, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported. Because of this most websites recommend at least an 8-inch (200 mm) telescope with an [O III] filter to find this object although probably possible to image with smaller apertures.[citation needed]

See also[edit]


  1. ^ a b c d "MEDUSA -- Planetary Nebula". Centre de Données astronomiques de Strasbourg. Retrieved 2010-07-01.
  2. ^ a b Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; et al. (June 2003). "2MASS All Sky Catalog of point sources". The IRSA 2MASS All-Sky Point Source Catalog, NASA/IPAC Infrared Science Archive.
  3. ^ a b Nemiroff, R.; Bonnell, J., eds. (12 June 2010). "The Medusa Nebula". Astronomy Picture of the Day. NASA. Retrieved 2010-07-01.
  4. ^ a b Lozinskaya, T. A. (June 1973). "Interferometry of the Medusa Nebula A21 (YM 29)". Soviet Astronomy. ADS. 16: 945. Bibcode:1973SvA....16..945L.

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