Planetary Nebula NGC 7139
NGC 7139 was discovered on 5 November 1787 by the German-British astronomer Wilhelm Herschel and identified as a planetary nebula by the American astronomer Heber Doust Curtis in 1918.
The apparent visual magnitude of NGC 7139 is about 13 magnitudes. The distance determination of planetary nebulae is often not reliable. In 2008 it gave a distance of about 1400 parsecs, about 4500 light years. Older estimates went from 2400 parsecs, about 7800 light years. [132, 141, 145, 196, 349]
|Designations||PN G104.1+07.9: NGC 7139, PK 104+07.1, ARO 54, VV 270, VV' 557|
|Right Ascension (J2000.0)||21h 46m 10s|
|Declination (J2000.0)||+63° 47' 16"|
|Radial Velocity||-54.4 km/s ± 3.4 km/s|
|Expansion Velocity||19.5 km/s (O-III)|
|C-Star Designations||AG82 436|
|C-Star Magnitude||18.72 mag (V filter)|
The planetary nebula NGC 7139 is located in the constellation Cepheus. The best viewing time is May to December when the constellation is highest in the night sky.