How did William Herschel’s nebula catalogs influence the New General Catalogue?

The catalogs compiled by William Herschel, along with those of his son John Herschel, served as the foundational basis for the New General Catalogue (NGC).12

Between 1786 and 1802, William Herschel, assisted by his sister Caroline Herschel, cataloged approximately 2,500 nebulae, star clusters, and galaxies. When J.L. Dreyer published the NGC in 1888, he incorporated these extensive observations into a comprehensive reference list that ultimately included 7,840 celestial objects.12

The legacy of the Herschels' work remains significant today, as many of the brighter galaxies and nebulae are still identified by their original NGC numbers. This collection was later expanded by the Index Catalogues, which added thousands of additional objects to the record.12