History

The planetary nebula Abell 40 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 was then listed as number 28 (A55 28). 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 nebula 40 (A66 40). He described it with «B» as «a homogeneous ring» ^{[331, 332]}

The designation PK 359+15.1 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]

Physical Properties