astrocalc 0.0.1

A library for calculating sun and moon positions and phases.

AstroCalc

This library is a Dart port of the awesome Vladimir Agafonkin (@mourner)'s JavaScript library for calculating sun and moon positions and phases for a given location and time.

Calculations for other solar system bodies are also in the works.

Usage

AstroCalc is available on Pub.

See the examples folder for usage examples.

Reference

BaseCalc

// Latitude and longitude in degrees
BaseCalc baseCalcChild = BaseCalcChild({ DateTime date, num longitude, num latitude })

All celestial body classes inherit from the abstract class BaseCalc. On instantiation, they all calculate and expose the following properties of the body for the provided location and time (each is a Map):

Property	Description
eclipticCoords	Earth-based ecliptic coordinates: latitude (eclipticCoords['lat']) and longitude (eclipticCoords['lng'])
equatorialCoords	Equatorial coordinates: right ascension (equatorialCoords['ra'] and declination equatorialCoords['dec'])
position	Earth-based horizontal coordinates: azimuth (position['azimuth']) and altitude (position['altitude'])
times	Times of astronomical interest (body-specific)

The coordinate systems are returned in radians. For more information on each, see the following links:

• Ecliptic coordinate system
• Equatorial coordinate system
• Horizontal coordinate system

SunCalc

SunCalc sunCalc = new SunCalc({ DateTime date, num longitude, num latitude })

In addition to the coordinate systems, SunCalc calculates the following times (accessible as properties of the Map sunCalc.times)

Property	Description
nightEnd	night ends (morning astronomical dawn starts)
nauticalDawn	nautical dawn (morning nautical dawn starts)
dawn	dawn (morning nautical dawn ends, morning civil dawn starts)
sunrise	sunrise (top edge of the sun appears on the horizon)
sunriseEnd	sunrise ends (bottom edge of the sun touches the horizon)
goldenHourEnd	morning golden hour (soft light, best time for photography) ends
solarNoon	solar noon (sun is in the highest position)
goldenHour	evening golden hour starts
sunsetStart	sunset starts (bottom edge of the sun touches the horizon)
sunset	sunset (sun disappears below the horizon, evening civil twilight starts)
dusk	dusk (evening nautical twilight starts)
nauticalDusk	nautical dusk (evening astronomical twilight starts)
night	night starts (dark enough for astronomical observations)
nadir	nadir (darkest moment of the night, sun is in the lowest position)