The Observatory Today - Missions and Services
Today’s USNO is a major authority in time-keeping and celestial tracking. It calculates and distributes the astronomical and timing data needed for accurate navigation and fundamental astronomy tasks, then distributes the information in the Astronomical Almanac, which contains catalogs of selected stellar and extragalactic objects. An explanatory supplement provides detailed analysis of the methods used in the Almanac. Until 1981, the British and the Americans created navigational almanacs, but at that time the two publications were combined into a publication called The Astronomical Almanac.
In addition to the almanac, the USNO maintains star catalogs and fundamental reference frames necessary for space astrometry. Astronomical data calculators and moon phases, rising and setting times, and other information are also kept by the USNO. It is also a source of daily, weekly, and long-term Earth observation products, Global Positioning Satellite (GPS)-based products, and other scientific information and software. The observatory’s web portal, http://www.usno.navy.mil has a number of resources for people who are interested in sky watching and weather data.
Among the data offered are sun and moon rising and setting times, moon phases, eclipses, seasons, and positions of solar system objects. A feature called “The Sky This Week" gives information about celestial configurations and other information of interest to astronomers and amateur sky watchers.