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

Eclipses and Transits

• Eclipses Online Portal
  Maps, global circumstances, local circumstances, and animations for all solar and lunar eclipses from 1501 through 2100 inclusive
• Eclipses of the Sun and Moon
  Eclipse Visibility Maps from The Astronomical Almanac
• 2017 August 21 Total Solar Eclipse
  Resource center for the 2017 eclipse crossing the continental United States
• 2023 October 14 Annular Solar Eclipse
  Resource center for the 2023 eclipse crossing the continental United States
• 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
• Transits of Mercury and Venus
  World maps of visibility, geocentric data, and event times for major cities from The Astronomical Almanac
• 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
  Provides tables of the altitude and azimuth of the Sun or Moon for a specified location and time interval
• Topocentric Configuration of Major Solar System Bodies
  Provides tables of low-precision topocentric positions for the Sun, Moon, major planets, and Pluto
• Geocentric Positions of Major Solar System Objects and Bright Stars
  Provides high-precision geocentric positions for the Sun, Moon, major planets, Pluto, and selected bright stars
• Topocentric Positions of Major Solar System Objects and Bright Stars
  Provides high-precision topocentric positions for the Sun, Moon, major planets, Pluto, and selected bright stars

Dates and Times

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

Celestial Navigation

• Celestial Navigation Data for Assumed Position and Time
  Computes almanac data for navigational stars and solar system bodies for an assumed position and time
• Navigational Star Chart

Data Services Documentation

• Application Programming Interface Documentation
• Printing and Exporting Data