NGC 7039: A Cluster in Cygnus’ Sea of Stars

Posted byWayne McGrawPosted inStar ClustersTags:, ,

NGC 7039 is an open star cluster of nearly 100 stars in the constellation Cygnus. The cluster is best viewed in late summer or early autumn.

Cygnus is a rich area full of nebula and star clusters, so it’s easy to overlook clusters like NGC 7039 as they are nestled among a dense area of stars. Some sources estimate NGC 7039 to span as wide as 25 arc-minutes. This is almost the diameter of a full moon, so it’s a good reminder to use lower-power eyepieces when targeting this cluster. The cluster is at a magnitude of +7.9, though many of its stars a much dimmer. View this page on Anthony Ayiomamitis’ site for a good photo of the cluster.

John William Herschel first recorded NGC 7039 in the year 1829.

My Observations

DateOctober 28, 2022
Time8:00 p.m.
LocationSeattle, WA
Magnification113x
ScopeMeade 8″ SCT
Eyepiece18mm
SeeingAverage
TransparencyAverage
Sketch of open star cluster NGC 7039, which lies at nearly 25 arc minutes in diameter in the constellation Cygnus. The cluster has around 100 dim stars, but under light polluted skies, one can pick out about 15 of them, the largest ones making a "V" pattern.
Sketch of NGC 7039 on October 28, 2022

I’m struggling at the moment to know if I’m seeing the entire cluster or if I’m zooming in too much. The pattern of the stars matches other images I’ve seen, but it appears the light-polluted skies skew my overall view of the cluster. I know I should be seeing many more dimmer stars, but they are not coming out; meanwhile, I’m sketching 6-7 brighter stars that make a “V” pattern. The cluster sits in front of a busy starfield.

Key Stats

ConstellationCygnus
Best ViewingSummer
Visual Magnitude+7.6
Absolute Magnitude-2.3
Distance from Earth3,100 ly
Diameter25 ly
Milky Way LocationOrion Spur
My Viewing GradeC+

Sources

  • With no photo of NGC 7039 available, the banner photo shows a general star field from Pexels Free Photos. Photo by Kai Pilger.
  • 1 Ayiomamitis, A. (2010, July 26). NGC 7039 – open cluster in Cygnus. NGC 7039 – open cluster in Cygnus – Astronomy Magazine – Interactive Star Charts, Planets, Meteors, Comets, Telescopes. Retrieved December 18, 2022, from https://cs.astronomy.com/asy/m/starclusters/450563.aspx
  • Sketch by Wayne McGraw

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