Although Hoffleit officially retired in 1975 at age 68, she continued to work daily from her office at Yale University until well into her 90s. Few of her peers — regardless of age or gender — have ever served more selflessly in the service of astronomy.
Her scientific interest blossomed early, at a time when female astronomers were few. She joined the American Association of Variable Star Observers in 1930 at age 23 and began working as a research assistant at Harvard College Observatory under Harlow Shapley.
Armed with an undergraduate degree in mathematics from Radcliffe College (1928) and then a doctorate in astronomy from Radcliffe (1938), Hoffleit persevered. She calculated missile trajectories during World War II and eventually joined the astronomy department at Yale. Among the hundreds of research articles she published during her career, 40 appeared in the Journal of the AAVSO.
Along the way Hoffleit lent her considerable talent to a fledgling publication called Sky & Telescope, writing the magazine's News Notes from its second issue in 1941 until the mid-1950s. She continued to write for S&T occasionally thereafter, with her final contribution (a book review) appearing in 1997.
Hoffleit will likely be remembered best for her seminal reference work, the Bright Star Catalogue (often called the Yale Bright Star Catalogue), which tabulates data on more than 9,000 stars to limiting magnitude 6.5. She was awarded the American Astronomical Society's George Van Biesbroeck Prize for her extraordinary service to astronomy in 1988 and its Annenberg Prize for science education in 1993.
In her spare time, Hoffleit took a special interest in young women pursuing astronomy, training college undergraduates during summer months from 1957 to 1978 at Maria Mitchell Observatory on Nantucket Island in Massachusetts.
Her autobiography, Misfortunes as Blessings in Disguise, was published in 2002 and is available from the AAVSO.