Astronomy

Overview

A suite of open source libraries for calculating positions of the Sun, Moon, and planets.

This code is designed to be small, fast, and accurate to within ±1 arcminute. It is based on the authoritative and well-tested models VSOP87 and NOVAS C 3.1.

Rigorously unit-tested against NOVAS, JPL Horizons, and other reliable sources of ephemeris data.

Features

• Provides calculations for the Sun, Moon, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

• Calculates for any calendar date and time between the years 1600 and 2200.

• Provides heliocentric and geocentric Cartesian vectors of all the above bodies.

• Determines apparent horizon-based positions for an observer anywhere on the Earth, given that observer's latitude, longitude, and elevation in meters. Optionally corrects for atmospheric refraction.

• Rise, set and culmination times of Sun, Moon, and planets.

• Date and time of Moon phases: new, first quarter, full, third quarter (or anywhere in between as expressed in degrees of ecliptic longitude).

• Finds equinoxes and solstices for a given calendar year.

• Finds apparent visual magnitudes of all the supported celestial bodies.

• Predicts dates of planetary conjunctions and oppositions.

• Predicts dates of Venus' peak visual magnitude.

• Predicts dates of maximum elongation for Mercury and Venus.

Supported Languages

JavaScript

API Reference

C/C++

(Coming soon.)

Go

(Coming soon.)

Python

(Coming soon.)