NGC6811, Massimo Torri

NGC6811

NGC6811, Massimo Torri

NGC6811

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Description

Open cluster NGC 6811 in the constellation of Cygnus is a cluster comprised of approximately 70 member stars. Curiously the central portion of the cluster is populated by only faint stars, giving the cluster a curious doughnut-shape which is quite obvious at the eyepiece. It is because of this trait that NGC6811 is sometimes referred to as the "Hole-in-a-cluster". The cluster spans 15 arc-minutes in diameter or half the apparent diameter of the full moon and lies at about 3,500 light-years away with an iage of approximately 700 million years old and as evidenced by the presence of some red giants and predominance of white hot stars in the image. The cluster is best observed using low magnifications (50-100x) during summer when it is directly overhead and can be found to lie just to the northeast of δ-Cyg (mag 2.90). NGC 6811 was discovered by John Herschel in 1829.

Technical Details:

Date: July 6, 2013 @ 00:00 - 2:30 UT-6

Location: Edmonton, Canada (53.5472° N, 113.5006° W)

Equipment: 10" Newtonian f/4.7, Losmandy G-11, Canon XSi

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Histogram

NGC6811, Massimo Torri