Astrodynamics, Orbits, & Time

Where it all starts:

United States Naval Observatory

Interactive Web Sites

• Artificial Satellites
  • Satellite Locator Form (SSC)
  • SatPasses: Predictions of Satellite Passes (Bester)
• Moon & Planets
  • Moon and Planetary Ephemerides (Innsbruck)
  • Small-Body Orbital Elements Generator (JPL)
• Sunrise/Sunset, Moonrise/Moonset
  • Astronomical Sky Calendar (Imagiware)
  • Compute Sunrise, Sunset & Twilight (CompuSolve)
  • Earth Viewer: Real-Time Terminator (Walker)
  • SunAngle Calculator (CREST)
  • Sunrise/Sunset/Twilight & Moonrise/Moonset/Phase (USNO)
• Time/Coordinates
  • COCO - Coordinate Converter (NASA)
  • Local Apparent Sidereal Time (USNO)
  • WebMICA: Multiyear Interactive Computer Almanac (USNO)
• Virtual Observatories
  • SkyView Virtual Observatory (NASA)

Resources

• Artificial Satellites
  • 4-Day Combined Orbits @ 50 RE (Wind, IMP-8, Interball, Geotail) (NASA)
  • Satellite Situation Center (NASA)
  • SatTrack: Tracking and Orbit Analysis Software for UNIX (Bester)
• Celestial Mechanics
  • SunAngle (CREST)
    • About Declination
    • About the Equation of Time
    • About Hour Angle
    • About Local Solar Time
    • About Solar Altitude Angle
    • About Solar Azimuth Angle
    • About Time of Sunrise/Sunset
  • Astrodynamic Constants and Parameters (JPL)
  • Astronomical Applications Data Online (USNO)
  • Earth Rotation and Equatorial Coordinates (NRAO)
  • IAU Resolutions (USNO)
  • Orbital Mechanics (Braeunig)
• Etc
  • Current Day and Night Locations on Earth (IPS)
  • Phase of the Moon (Osburn)
• Time
  • Astronomical Times (NRAO)
  • Time Service Department (USNO)

Free Software

• Earth and Moon Viewer (Walker)
• Spacecraft Orbit-Attitude Transformations (ftp) (NASA)
• XEPHEM: Interactive Astronomy Program for X-Windows/Motif (Downey)

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