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Tweedledee Cluster

Graff's Cluster, Secret Garden Cluster, IC 4756

Proper NamesTweedledee Cluster, Graff's Cluster, Secret Garden Cluster
Messier NumberNone
NGC/IC NumberIC 4756
Right Ascension18h 38m 31s
Declination+5° 29' 24"
Distancec.1,300 light years
c.400 parsecs
MagnitudeApparent: +5.4
Absolute: -7.6
DiameterApparent: 40'
Actual: c.15 light years
Optimum VisibilityJuly
NotesOne of a pair of open clusters that appear relatively close together in the sky (though in fact they are some three hundred light years apart). Among other informal names, this cluster is colloquially known as the Tweedledee Cluster, while its companion in the sky, just across the border in Ophiuchus, has been named the Tweedledum Cluster.

An open cluster of some eighty stars lying in the constellation Serpens, some 1,300 light years from Earth.

Location of IC 4756

IC 4756 lies near the tip of the Serpent's Tail, at the point where Serpens borders both Ophiuchus and Aquila, in a fairly dense region of the Milky Way.

Relative Galactic Position of IC 4756

IC 4756 is about 1,300 light years from the Sun: a vast distance in real terms, but hardly detectable on a Galactic scale.

IC 4756 against the Milky Way

The loose form of IC 4756 is distinguishable as a wide clump of stars against the rich background of the Milky Way.


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