Sky & Telescope - USA (2019-11)

skyandtelescope.com • NOVEMBER 2019 67

M27

Altair

M71

King 25

King 26

King 27

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AQUILA

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VULPECULA

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Aquila and Vulpecula

rating them from the background is quite satisfying and fulfi lling. For those

who enjoy both the aesthetics and scientifi c aspects of open clusters, several

references listed under “Further Reading” are highly recommended. After

all, having an appreciation of the scientifi c characteristics of open clusters,

such as their formation, age, size, mass, structure, composition, photometric

analysis, proper motion, and location in the Milky Way Galaxy, adds to your

enjoyment of their role in our local neighborhood. With more than 41 differ-

ent open cluster designations — the King clusters among them — the observer/

imager will be kept busy for many pleasurable sessions.

¢ When obsessed with various observing projects, AL LAMPERTI is rumored

not to be playing with a full deck! FRANK COLOSIMO has been observing at

the Blue Mountain Vista Observatory (star-watcher.org) for 12 years, which is

where he obtains his images. Both Al and Frank are members of the Delaware

Valley Amateur Astronomers.

FURTHER READING: For more information and specifi c details on open clusters,

see Star Clusters by Brent A. Archinal and Steven J. Hynes (Willmann-Bell, Inc.,

2003) and Star Clusters and How to Observe Them by Mark Allison (Springer-Verlag,

Ltd., 2006). For a table of parameters of the King clusters in this paper, go to

https://is.gd/KingClusters.

uKING 26 I note one fairly bright star on the west-
ern edge. The cluster seems a bit elongated, almost
triangular in shape with about 8 fainter stars. I detect
no concentration toward the center, a small popula-
tion of stars, and a wide range of magnitudes, all
consistent with the cluster’s Trumpler classifi cation.
Mv = unavailable | S = 2′ | No. = 15 | Tr = II1p | Mag. = 337×

uuKING 27 We appropriately conclude our tour
of open clusters in Vulpecula, with the last cluster
identifi ed by King, better known as Czernik 40. It’s a
fairly faint cluster and wide open. There was haziness
among the brighter, 10th-magnitude stars on the
periphery. The cluster stands out from the fi eld, even
with a poor number of stars.
Mv = unavailable | S = 4′ | No. = 30 | Tr = II2m | Mag. = 337×

5 ′ 5 ′

5 ′