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M11 - Wild Duck
Cluster
Open Cluster in Scutum

7/7/07,
1:00 AM
Cherry Springs, PA
Meade LX90 8" SCT
Meade DSI Color Camera
23 subs x 15 secs, unguided
Processed in Envisage and PS
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| Right
Ascension |
18 :
51.1 (h:m) |
|
Declination |
-06 : 16
(deg:m) |
| Distance |
6.0 (kly) |
| Visual
Brightness |
6.3 (mag)
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| Apparent
Dimension |
14.0
(arc min) |
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Discovered 1681 by
Gottfried Kirch.
The name
Wild Duck originated
from the "V-like" grouping of stars seen when observing visually. It
was described as "resembling the V-shape patterns of flying ducks (or
geese), although this is not evident in photos.
Messier 11 (M11, NGC 6705) is "One of the richest and most compact of the
galactic (open) clusters," to say it with Robert Burnham, Jr. M11 contains
an estimated 2900 stars, about 500 of which are brighter than mag 14. An
observer at the center of M11 would see several hundred first magnitude
stars! So rich and dense, it was classified by Trumpler as II,2,r (some
newer classifications have it as I,2,r).
The age of the Wild Duck cluster has been estimated to amount 220 million
years, as its brightest and hottest main sequence stars are of spectral
type B8 (according to the Sky Atlas 2000), but also double that value
(Burnham gives 500 million years). The higher value is supported by the
fact that this cluster also contains many yellow and red giants of
absolute magnitude around -1.0. G. Meynet's Geneva Team has recently
calculated its age at 250 million years. It is receding at 22 km/sec.
M11 was discovered by the German astronomer Gottfried Kirch of the Berlin
observatory in 1681. It was apparently first resolved into stars by
William Derham about 1733. Charles Messier included it in his catalog on
May 30, 1764.
*Much of the information regarding the Messier Objects and their origins has
been graciously provided by
www.seds.org/messier/
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