The code is available on GitHub here.
The part of this code that calculates Julian days can be used separately. Julian Days are a date format commonly used in astronomy. They count the number of days since noon, January 1st, 4713 BC. Time periods less than a day can be represented as fractional days.
There are four ways to create a JulianDay object.
var jd = JulianDay.fromValues(2012, 1, 1, 13, 20, 05, 988); console.log(jd.ephemerisDay(60)); console.log(jd.ephemerisCentury(60)); console.log(jd.ephemerisMillennium(60)); var date = jd.toDate();
They can be created
To actually perform the calculation, create a SolarPosition object providing as many of the parameters as you can.
var julianDay = JulianDay.fromValues(2012, 1, 1, 13, 20, 05, 988); var sp = new SolarPosition(julianDay, latitude, longitude, delta_t, elevation, pressure, temperature, slope, azm_rotation, atmos_refract); console.log(sp.getSunRiseTransitSet()); console.log(sp.getSunPosition()); console.log(sp.calculateGeocentricSunRightAscensionAndDeclination());