Planetary Nebula Abell 20
History
The planetary nebula Abell 20 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 first had the number 15 (A55 15). In 1966 Abell published a completed list including the size and description of the 86 planetary nebulae discovered on the POSS photo plates. The PN was then listed as number 20 (A66 20). He described the morphological appearance of the PN as «B» (a homogeneous ring). [331, 332]
The designation PK 214+7.1 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. [146]
The lesser known designation ARO 132 originates from 1971 survey of microwave radiation from planetary nebulae conducted by Canadian radioastronomer Lloyd A. Higgs using the 46-metre Algonquin Radio Observatory in Ontario, Canada. [136, 137]
Physical Properties
| Designations | PN G214.9+07.8: A 20, PK 214+07.1, A55 15, ARO 132, VV' 60 |
| Right Ascension (J2000.0) | 07h 22m 58s |
| Declination (J2000.0) | +01° 45' 37" |
| Dimensions | 67." (optical) |
| C-Star Designations | AG82 79, CSI +01 -07204, UBV 7149 |
| C-Star Magnitude | U: 15.17, B: 16.29, V: 16.56 |
| C-Star Spectral Type | O(H) |
| Discoverer | ABELL 1955 |
Finder Chart
The planetary nebula Abell 20 is in the constellation Canis Minor. It is best observed from October to April.
