Sean E UrbanSean E. Urban graduated from the University of Maryland with a degree in astronomy in 1984. In 1985, he was hired as a staff astronomer in the Astrometry Department of the US Naval Observatory, where he eventually rose to Chief of the Cataloging and equirements Division. In 2004, he became Chief of the Nautical Almanac Office of the US Naval Observatory, a position that he holds today. He has authored or co-authored more than 50 articles, most on positional astronomy. He is a member of the American Astronomical Society, the Division of Dynamical Astronomy, and the International Astronomical Union's Division I (Fundamental Astronomy), Commission 4 (Ephemerides), and Commission 8 (Astrometry). Read More Read Less