Palomar 5 was discovered by Walter Baade in 1950, and independently found again by A.G. Wilson in 1955 (A.G. Wilson 1955). Wilson named it the Serpens Globular Cluster, not necessarily a happy naming because Serpens also contains four more globulars, including famous M5. He published its discovery together with that of Palomar 3, Palomar 4 and Palomar 13, and two new Local Group galaxies. G.O. Abell (1955) cataloged them with their Palomar numbers.
Apparently unaware or unsure about its classification as a globular, it was temporarily taken for a nearby dwarf galaxy, of elliptical or spheroidal type, named the Serpens Dwarf, and suspected to be a Local Group member candidate because of its resolution into stars.
It was found that Palomar 5 is currently undergoing a process of tidal disruption by the gravitation of the Milky Way galaxy. Many former cluster mermber stars are moving away from it, forming tails in opposite directions which probably exist already for several billion years, and extends now over a length of over 13,000 light years.
The image on the right was obtained by Martin Germano.
This image was obtained by Chris & Dawn Schur, taken with their 12.5" f/5 Home made Newtonian and SBIG ST7E CCD camera with Enhanced Cooling, from Payson, Arizona. It is an LRGB composite of exposures LRGB = 60:10:10:10 min.