Williamina Fleming discovered the Horsehead Nebula.
On November 10, 1888, Williamina Fleming discovered the Horsehead Nebula, a dark nebula in the Orion constellation. Using photographic plates at Harvard College Observatory, her discovery represented a major achievement for women in astronomy. The nebula became a significant object of study due to its distinct shape and the insight it provided into stellar formation. Williamina's work highlighted the importance of women in scientific discovery at a time when their contributions were often overlooked.