Medusa nebula, 24 inch telescope on Mt. Lemmon, AZ.
|Observation data: J2000.0 epoch|
|Right ascension||07h 29m 02.69s|
|Declination||+13° 14′ 48.4″|
|Distance||1,500 ly (460 pc) ly|
|Apparent magnitude (V)||15.99|
|Apparent dimensions (V)||4 ly|
|Absolute magnitude (V)||7.68|
|Notable features||Very large & very low surface brightness|
|Designations||Sharpless 2-274, PK 205+14 1, Abel 21 |
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. 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.
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.
- "MEDUSA -- Planetary Nebula". Centre de Données astronomiques de Strasbourg. Retrieved 2010-07-01.
- 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. Bibcode:2003tmc..book.....C.
- Nemiroff, R.; Bonnell, J., eds. (12 June 2010). "The Medusa Nebula". Astronomy Picture of the Day. NASA. Retrieved 2010-07-01.
- Lozinskaya, T. A. (June 1973). "Interferometry of the Medusa Nebula A21 (YM 29)". Soviet Astronomy. ADS. 16: 945. Bibcode:1973SvA....16..945L.