Planetary Nebula NGC 6742

NGC 6742
NGC 6742: Planetary nebula in Draco; 500 mm Cassegrain 3625 mm f/7.2; SBIG STL11K; 70+3*20 min LRGB; Bernese Highlands; © 2015 Radek Chromik

History

Nebula NGC 6742 was discovered by Wilhelm Herschel on July 8, 1788 and also observed by Heinrich d'Arrest on September 24, 1862. John L. E. Dreyer described the nebula as very faint and stellar. George Ogden Abell then identified NGC 6742 as his 39th planetary nebula (A55 39) on the «Palomar Observatory Sky Survey» (POSS) photoplates in 1955 and then listed it as No. 50 in his list of 86 on the POSS photoplates in 1966 discovered PNs (A66 50). The PN Abell 50 should not be confused with the galaxy cluster Abell 50 (ACO 50) of the same name in the constellation Cetus. [196, 331, 332]

Physical Properties

The distance is given as 5091 pc (about 16'600 light years) and the visual apparent magnitude as 16.5 mag. The central star is of the spectral type O(H)III-V [145]

Finder Chart

Planetary nebula NGC 6742 is located in the constellation Draco, near the border of Lyra and Cygnus. In Central Europe it is circumpolar. The best observing time is April to October, when the PN is highest in the night sky.

Chart NGC 6742
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
331«Globular Clusters and Planetary Nebulae Discovered on the National Geographic Society-Palomar Observatory Sky Survey» Abell, G. O.; Publications of the Astronomical Society of the Pacific, Vol. 67, No. 397, p.258-261, August 1955; DOI:10.1086/126815; Bibcode:1955PASP...67..258A
332«Properties of Some Old Planetary Nebulae» Abell, G. O.; Astrophysical Journal, vol. 144, p.259, April 1966; DOI:10.1086/148602; Bibcode:1966ApJ...144..259A