readme.md 1.3 KB
#Planet positions
Computes planet positions, plus the Earth's Moon, on any given UTC time.
##Usage
Include planet-positions.js (or planet-positions.min.js), then call
var planets = window.lagrange.planet_positions.getPositions(new Date());
An array of objects will be returned, one for each planet, with a Three.js Vector3 as the planet's position. If you also want to receive the planet's velocity as a Vector3, specify a second parameter set to true.
{
name: 'earth',
position: Three.Vector3,
velocity: Three.Vector3
}
Credits
- Planets orbital elements were taken from Nasa's Jet Propulsion Laboratory.
- I learned about calculating positions from orbital elements by reading these documents by Keith Burnett, Paul Schlyter and E M Standish (JPL).
- David Eagle for orbital calculations of the moon, based on "Lunar Tables and Programs From 4000 B.C. TO A.D. 8000" by Michelle Chapront-Touze and Jean Chapront. See mathworks.com.
More details on La Grange's blog at http://lab.la-grange.ca/en/jsorrery