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.
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NGC 7721
NGC 7721 is a spiral galaxy located around 79 million light-years away in the constellation Aquarius. NGC 7721 was discovered on September 10, 1785, by the astronomer William Herschel, and its diameter is 70,000 light-years across. NGC 7721 is not known to have much star formation, and it is not known to have an active galactic nucleus. A supernova was observed in NGC 7721 in 2007, named 2007le.
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Wikipedia Page: NGC 7721
NGC 7721 at In-The-Sky website