data services

Rise/Set/Transit/Twilight Data

• Complete Sun and Moon Data for One Day
• Table of Sunrise/Sunset, Moonrise/Moonset, or Twilight Times for an Entire Year
• Rise/Set/Transit Times for Major Solar System Objects and Bright Stars
• Duration of Daylight/Darkness Table for One Year

Phases of the Moon

• Dates of Primary Phases of the Moon
• Fraction of the Moon Illuminated
• What the Moon Looks Like Now

Eclipses and Transits

• USNO/HMNAO Eclipse Portal
  Maps, global circumstances, local circumstances, and animations for all solar and lunar eclipses from 1501 to 2100 inclusive.
• 2024 April 8 Total Solar Eclipse
  Resource center for the 2024 eclipse crossing the continental United States.
• Solar Eclipse Computer
  Computes circumstances for selected solar eclipses at any given location.
• Lunar Eclipse Computer
  Computes circumstances for selected lunar eclipses at any given location.
• Recent and Upcoming Transits of Mercury and Venus
• Transit Computer
  Computes circumstances for selected transits of Mercury and Venus at any given location.

Positions of Selected Celestial Objects

• Altitude and Azimuth of the Sun or Moon During One Day
• Topocentric Configuration of Major Solar System Bodies
  Provides tables of low precision topocentric position data for the Sun, Moon, and major planets.
• Geocentric Positions of Major Solar System Objects and Bright Stars
  Provides high precision geocentric position data for the Sun, Moon, major planets and selected bright stars.
• Topocentric Positions of Major Solar System Objects and Bright Stars
  Provides high precision topocentric position data for the Sun, Moon, major planets and selected bright stars.

Synthetic Views of the Earth and Solar System Bodies

• What Earth Looks Like Now
• Day and Night Across the Earth
  Creates synthetic views of the Earth's surface for any date and time.
• Apparent Disk of Solar System Object
  Creates a synthetic image of the telescopic appearance of the Moon or other solar system object for specified date and time.

Dates

• Earth's Seasons - Equinoxes, Solstices, Perihelion, and Aphelion
• Julian Date Conversion
• Sidereal Time

Celestial Navigation

• Celestial Navigation Data
  Provides computed altitudes and azimuths and other data for an assumed position and time.
• Navigational Star Chart