Julena Steinheider Duncombe (1911–2003) was an American mathematician and astronomer. She was known for her work as a teacher at the Heart Mountain Relocation Center and as an astronomer at the United States Naval Observatory, where she made pioneering observations with the 6-inch transit circle, introduced the use of punched cards in cataloging stars and constructing tables of positions of celestial bodies, and led the production of eclipse predictions for almanacs.[1][2]