The New General Catalogue of Nebulae and Clusters of Stars (abbreviated as NGC) is a catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, known as the NGC objects. It is one of the largest comprehensive catalogues, as it includes all types of deep space objects, including galaxies, star clusters, emission nebulae and absorption nebulae.
Know more about NGC
NGC 4439
NGC4439 (Open cluster)
Sources:
Wikipedia Page: NGC 4439
NGC 4439 at In-The-Sky website