Astronomer Caroline Herschel observed her first comet on 1 August 1786 an anniversary that was celebrated by various people on Twitter yesterday. Unfortunately many of them, including for example NASA History Office (@NASAhistory), claimed that on this date she became the 1st woman to discover a comet. This is quite simply not true.
Maria Margarethe Kirch (née Winkelmann), the wife of Gottfried Kirch the Astronomer Royal of Berlin, discovered the comet of 1702 (C/1702 H1) on 21 March 1702 that is forty-eight years before Caroline Herschel was born. Unfortunately the discovery was published by her husband and it was he who was incorrectly acknowledged as the discoverer. In 1710 Gottfried admitted the error and publically acknowledged Maria as the discoverer but she was never official credited with the discovery.
Both Maria Kirch and Caroline Herschel were excellent astronomers with much important work to their credit. However credit where credit is due, Caroline was not the first woman to discover a comet, Maria was.