Planetary Nebula Abell 26
The planetary nebula Abell 26 was discovered in 1964 by the American astronomer George Ogden Abell on the photo plates of the Palomar Observatory Sky Survey (POSS). 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 26 (A66 26). He described the morphological appearance of the PN as «a» (a homogeneous disk). 
The designation PK 250+0.1 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. The numbering is derived from galactic coordinates and the decimal number refers to the order of the planetary nebula discovered in the 1°x1° square. 
The lesser known designation ARO 545 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]
The planetary nebula Abell 26 is in the constellation Puppis It is best observed from November to February, although in Switzerland it rises only about 10° above the southern horizon.