Table of Contents¶
Welcome to the documentation for Skyfield, the pure Python astronomy library that is accelerated using NumPy vector math!
- Installing Skyfield
- Examples
- What time is solar noon, when the Sun transits the meridian?
- When will it get dark tonight?
- What phase is the Moon tonight?
- What is the angular diameter of a planet, given its radius?
- When is Venus at its greatest east and west elongations from the Sun?
- Are planets separated by 0° at conjunction and 180° at opposition?
- At what angle in the sky is the crescent Moon?
- When is a body or fixed coordinate above the horizon?
- At what rate is a target moving across the sky?
- What is the right ascension and declination of a point in the sky?
- What latitude and longitude is beneath this right ascension and declination?
- Which geographic location is farther from Earth’s center?
- Example Plots
- Downloading and Using Data Files
- Almanac Computation
- Positions
- Coordinates
- Cartesian coordinates versus Spherical coordinates
- ICRS and equatorial right ascension and declination
- Horizonal coordinates
- Hour Angle and Declination
- ECI versus ECEF coordinates
- Geographic ITRS latitude and longitude
- Ecliptic coordinates
- Galactic coordinates
- Velocity
- Turning coordinates into a position
- Rotation Matrices
- Dates and Time
- Planets and their moons: JPL ephemeris files
- Stars and Distant Objects
- Planetary Reference Frames
- Kepler Orbits
- Earth Satellites
- Loading a TLE file
- Performing a TLE query
- Loading a TLE set from strings
- Checking a TLE’s epoch
- Historical satellite element sets
- Finding when a satellite rises and sets
- Generating a satellite position
- Satellite longitude, latitude, and height
- Satellite altitude, azimuth, and distance
- Satellite right ascension and declination
- Find a satellite’s range rate
- Find when a satellite is in sunlight
- Find whether the Earth blocks a satellite’s view
- Avoid calling the observe method
- Detecting Propagation Errors
- Build a satellite with a specific gravity model
- Build a satellite from orbital elements
- Searching for the dates of astronomical events
- Skyfield’s Accuracy and Efficiency
- Osculating Orbital Elements
- Using Skyfield with AstroPy
- API Reference
- Version
- Opening files
- Time scales
- Time objects
- Time utilities
- Vector functions
- Planetary ephemerides
- Planetary magnitudes
- Planetary reference frames
- Almanac
- Geographic locations
- Kepler orbits
- Kepler orbit data
- Earth satellites
- Stars and other distant objects
- Astronomical positions
- Reference frames
- Constellations
- Searching
- Osculating orbital elements
- Units
- Trigonometry
- API Reference — Opening Files
- API Reference — Time
- API Reference — Vector Functions
- API Reference — Planetary Ephemerides
- API Reference — Geographic Locations
- API Reference — Almanac
- API Reference — Earth Satellites
- API Reference — Stars and other distant objects
- API Reference — Astronomical Positions
- Generic ICRF position
- Position measured from the Solar System barycenter
- Astrometric position relative to an observer
- Apparent position relative to an observer
- Geocentric position relative to the Earth
- Geometric instantaneous position between two objects
- Building a position from right ascension and declination
- API Reference — Reference Frames
- API Reference — Planetary reference frames
- API Reference — Kepler Orbits
- API Reference — Orbital Elements
- API Reference — Units
- API Reference — Trigonometry
- Design Notes
- Bibliography