Planetary Nebula Hubble 12
This planetary nebula was discovered by the famous astronomer Edwin Hubble in 1921 on photo plates taken with a 10-inch Cooke Astrographic Lens, 45-inch focus, with objective prisms attached, and have been checked by observations with the large reflectors on Mount Wilson Observatory. 
Hubble 12 (Hb 12; PN G111.8-02.8) is a young planetary nebula with a high surface brightness. It shows three pairs of bipolar structures and an arc-shaped filament near the western waist. Together with the presence of H2 knots it suggests that these structures originated from several mass-ejection events during the pre-PN phase. The central star is a binary. The kinematic age of the nebula ranges from about 300 yr for the innermost structure to 1120 yr for entire object. The determined distances of the PN vary between 2.24 kpc and 14.25 kpc.  Apparent magnitudes with different filters: B 13.51; V 11.49; R 12.44; J 10.23; H 9.82; K 8.81 
|Designations||PN G111.8-02.8: Hb 12, PK 111-02.1, ARO 381, VV 286, VV'576|
|Right Ascension (J2000.0)||23h 26m 15s|
|Declination (J2000.0)||+58° 10' 55"|
|Dimensions||1." (optical), 0.7" (radio)|
|Radial Velocity||-5.0 km/s ± 2.3 km/s|
|Expansion Velocity||14. km/s (O-III)|
|C-Star Designations||AG82 452|
|C-Star Magnitude||14.5 mag (B filter), 13.8 mag (V filter)|
|C-Star Spectral Type||WN 7?|
The planetary nebula Hubble 12 is located between the constellations Cassiopeia and Cepheus. It is circumpolar in Central Europe, but the best observation time is July to January, when it is highest at night.
Description pending ...