The Harvard College Observatory is a research facility located in Cambridge, Massachusetts, established in 1839. It is part of Harvard University and focuses on astronomical research and education. The observatory has played a significant role in the development of modern astronomy, contributing to the discovery of various celestial phenomena. The observatory is known for its extensive collection of astronomical photographs and data, which have been used in numerous studies. It has also been involved in the training of many prominent astronomers, including Henrietta Leavitt, who made important contributions to the understanding of variable stars.