Open Clusters
64 NOVEMBER 2019 • SKY & TELESCOPE
M36M37M38King 22f¡cd+_hlm`eAURIGACapella5 h 40 m 5 h 20 m 5 h 00 m+40°+35°+45°King 8St King 17armagni
tudes 2
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7Visually tackling the King list requires dark skies, increased
aperture, and high magnifi cation. Over the years, I have
observed each of the King open clusters with refl ector tele-
scopes ranging from 18 to 22 inches. The more recent obser-
vations were made with a 22-inch refl ector. The challenge in
fi nding, observing, and resolving the clusters is due, in part,
to their intrinsic brightness, their age, and their greater dis-
tance from us. For example, the average distance to the two
members of the Double Cluster is 7,200 light-years, whereas
that of the King open clusters is almost 10,000 light-years.(continued from page 60)Auriga
qKING 5 In the northern reaches of Perseus, King 5 is a faint yet
resolvable open cluster.
Mv* = 13 | S = 6′ | No. = 40 | Tr = I2m | Mag. = 98×qKING 6 Across the border in Camelopardalis, King 6 is a scattering
of bright stars along with many faint stars, and elongated in shape.
Mv* = 10 | S = 10′ | No. = 35 | Tr = II2m | Mag. = 208×qqKING 7 This is a very dim open cluster, with one bright star sur-
rounded by haze, making it hard to classify.
Mv* = 16 | S = 8′ | No. = 80 | Tr = I2r | Mag. = 272×Interestingly, the average age of the Double Cluster, which
is composed of “young” bright stars, is 11.3 million years,
whereas the King clusters average 1.1 billion years, or
nearly 100 times older!
The observer shouldn’t automatically dismiss a King
open cluster even if its magnitude appears to be beyond
the capability of their telescope. Sky conditions, position
in the sky, magnifi cation, experience, and persistence may
prove the numbers deceiving.
Within these pages are images provided by Frank Colo-
simo accompanied by my observing notes. Frank obtained5 ′ 5 ′5 ′