NGC 6539 -- Globular Cluster in Serpens Cauda
NGC 6539 -- A Globular Belonging to Two Constellations
The faint, moderate-sized, Globular Cluster NGC 6539 is three-fifths in the
constellation of the Snake’s Tail (Serpens Cauda) and two-fifths in the
Serpent Bearer (Ophiuchus).  Since most is in Serpens Cauda that is the
constellation that it is assigned to.  This cluster is below the resolution of my
small refractor and presents itself (on the best of nights) only as a faint misty
patch of ephemeral light.