Planetary Nebula Abell 71

Abell 71
Abell 71: Planetary nebula in Cygnus; 500 mm Cassegrain f=5800 mm f/11.4; SBIG STL11K; 60+10+10+10 min LRGB; Bernese Highlands; © 2005 Radek Chromik


The planetary nebula Abell 71 (PK 85+4.1) was discovered in 1955 by the American astronomer George Ogden Abell on the photo plates of the “Palomar Observatory Sky Survey” (POSS). In 1955 he published a first list of 13 globular clusters and the positions of 73 planetary nebulae. The PN had the number 58 (A55 58). Stewart Sharpless added the nebula to his catalog of H-II regions as Sh2-116 in 1959. Due to its size and low brightness, it probably did not recognize it as a planetary nebula. In 1966 Abell published a complete list including the size and description of the 86 planetary nebulae discovered on the POSS photo plates. The designation PK 85+4.1 originates from the two Czechoslovak astronomers Luboš Perek and Luboš Kohoutek, who in 1967 compiled a catalog of all the planetary nebulae of the Milky Way known at the time. [331, 332]

Physical Properties

Abell 79 is very large with an angular diameter of around 2.6 arc minutes, but has a very low surface brightness with 19 magnitudes. This suggests an advanced age. The distance was determined to be 729 parsecs (around 2400 light years) in 2008. [145]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
DesignationsPN G084.9+04.4: A 71, PK 85+04.1, A55 58, ARO 352, Sh 2-116, VV' 537
Right Ascension (J2000.0)20h 32m 24s
Declination (J2000.0)47° 21' 04"
Dimensions 157." (optical)
Expansion Velocity 10. km/s (O-III), 20. km/s (N-II)
C-Star DesignationsAG82 412, CSI +47 -20308, UBV 17830
C-Star Magnitude18.66 mag (U filter), 19.32 mag (B filter), 18.95 mag (V filter)
DiscovererABELL 1955

Finder Chart

The planetary nebula Abell 71 is located in the constellation Cygnus (swan). The best observation time is April to November.

Chart Abell 71
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]


141Strasbourg-ESO Catalogue of Galactic Planetary Nebulae; A. Acker, F. Ochsenbein, B. Stenholm, R. Tylenda, J. Marcout, C. Schohn; European Southern Observatory; ISBN 3-923524-41-2 (1992); (2021-02-18)
145SIMBAD astronomical database;
149SkySafari 6 Pro, Simulation Curriculum;
160The STScI Digitized Sky Survey;
331«Globular Clusters and Planetary Nebulae Discovered on the National Geographic Society-Palomar Observatory Sky Survey» Abell, G. O.; Publications of the Astronomical Society of the Pacific, Vol. 67, No. 397, p.258-261, August 1955; DOI:10.1086/126815; Bibcode:1955PASP...67..258A
332«Properties of Some Old Planetary Nebulae» Abell, G. O.; Astrophysical Journal, vol. 144, p.259, April 1966; DOI:10.1086/148602; Bibcode:1966ApJ...144..259A