NGC 521, also occasionally referred to as PGC 5190 or UGC 962, is a barred spiral galaxy located approximately 224 million light-years from the Solar System[4] in the constellation Cetus.

[5] Herschel described his discovery as "faint, pretty large, irregular round, brighter middle".

Further observations were made by both his son, John Herschel, who simply noted "big" on his first and "very faint" on his second observation, as well as R. J. Mitchell, who noted "pretty big, spiral galaxy, disc enveloped in faint outlying neby and looks like an unresolved cluster.

[5] Three supernovae have been observed in NGC 521: The galaxy's large apparent size can be attributed to the fact that it is face-on.

[2] The object's distance of roughly 220 million light-years from the Solar System can be estimated using its redshift and Hubble's law.