The Astronomical Applications Department of the U.S. Naval Observatory computes, from fundamental astronomical reference data, the position, brightness, and other observable characteristics of celestial bodies, as well as the circumstances of astronomical phenomena.

This information is of critical importance to navigation, military operations planning, scientific research, surveying, accident reconstruction, architecture, and everyday activities.

The products of the AA Department - publications, software, Web services, algorithms, and expertise - are used by the U.S. Navy and the other armed services, civilian government agencies, the scientific research community, and the public. Our products are regarded as benchmark standards throughout the world.

The department also conducts scientific studies in celestial mechanics, navigation, and positional astronomy to enable it to meet future needs.