(early 20th century spectroscopic catalog of stars)
The Henry Draper Catalog (abbreviated HD)
is an astronomical catalog of stellar spectra
published 1918-1924 of 225,300 stars.
Subsequent expansions cover an additional 100,000 stars,
e.g., the Henry Draper Extension (HDE), continuing the
numbering.
The catalog was funded in honor of amateur astronomer Henry Draper,
who in the 1800s made the first photographs of a star's spectrum.