Planetary Nebula Abell 39
The planetary nebula Abell 39 (PN A55 27, PN A66 39, PK 47+42.1) was discovered in 1955 by the American astronomer George Ogden Abell on the photo plates of the «Palomar Observatory Sky Survey» (POSS). In 1966 he published a list of a total of 86 planetary nebulae discovered on the POSS photo plates. [331, 332]
Abell 39 shows an almost perfect spherical bubble like a picture book for a planetary nebula. The western edge is about 50% brighter than the eastern. The central star is also not exactly in the center, but offset by about 2". It seems that this is due to a slightly asymmetrical ejection of matter and not an interaction with interstellar matter. It is estimated that the central star and the ejected material each have 0.6 solar masses. 
Distances from planetary nebulae are naturally quite imprecise. Those of Abbel 39 range from 1011 parsecs (2018) to 1175 parsecs (2008), which corresponds to 3300 to 3800 light years. Older estimates are at 2100 parsecs, about 6800 light years. The apparent brightness is measured by different filters: B 15.27 mag, V 15.6 mag, J 16.1 mag. 
|Designations||PN G047.0+42.4: A 39, PK 47+42.1, A55 27, ARO 180, VV' 140|
|Right Ascension (J2000.0)||16h 27m 33s|
|Declination (J2000.0)||+27° 54' 35"|
|Expansion Velocity||32. km/s (O-III), 37. km/s (N-II)|
|C-Star Designations||AG82 209, CSI +28 -16255, UBV 13929|
|C-Star Magnitude||14.10 mag (U filter), 15.34 mag (B filter), 15.69 mag (V filter)|
|C-Star Spectral Type||sd O, Hg O(H)|
The planetary nebula Abell 39 is located in the constellation Hercules. The best observation time is April to August.
Description pending ...