net.audumla.astronomy.algorithims.EllipticalObject.java Source code

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Here is the source code for net.audumla.astronomy.algorithims.EllipticalObject.java

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package net.audumla.astronomy.algorithims;

/*
 * *********************************************************************
 *  ORGANIZATION : audumla.net
 *  More information about this project can be found at the following locations:
 *  http://www.audumla.net/
 *  http://audumla.googlecode.com/
 * *********************************************************************
 *  Copyright (C) 2012 - 2013 Audumla.net
 *  Licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
 *  You may not use this file except in compliance with the License located at http://creativecommons.org/licenses/by-nc-nd/3.0/
 *
 *  Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
 *  "AS IS BASIS", WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and limitations under the License.
 */

import net.audumla.astronomy.CelestialObject;
import net.audumla.astronomy.Geolocation;
import net.audumla.astronomy.TransitDetails;
import org.apache.commons.lang3.time.DateUtils;

import java.util.Date;

public abstract class EllipticalObject implements CelestialObject {

    protected EllipticalObject() {
    }

    public abstract double eclipticLongitude(double JD);

    public abstract double eclipticLatitude(double JD);

    public abstract double radiusVector(double JD);

    @Override
    public TransitDetails getTransitDetails(Date date, Geolocation location, double altitude) {
        // to make sure that the dates for rise and set are for the correct day this code checks the resultant rise and set days.
        // as all times are calculated using UTC there is a chance that they may not be for the requested local day.
        // I have attempted to adjust the passed in time using the local time offset however this has not worked, so a
        // brute force method has been applied to recalculate using either the next or previous day.
        // this method has also run into problems when adjusting by +/- 24 hours. It appears that borderline cases may actually
        // cause the calculation to jump another whole day and therefore result in a calculation that is another full day in the
        // desired direction. Currently it appears that using +/- 23 hours will fix this as the borderline cases are as result
        // of the few seconds/minutes difference in rise times each day. This needs to be monitored however and more thorough testing applied.
        JulianTransitDetails details = calcTransitDetails(date, location, altitude);
        JulianTransitDetails detailsAdj = null;
        if (!DateUtils.isSameDay(date, details.getRiseTime())) {
            detailsAdj = calcTransitDetails(DateUtils.addHours(date, date.after(date) ? 23 : -23), location,
                    altitude);
            details.setRise((detailsAdj.getJulianRise().julian() - details.getReferenceTime().julian()) * 24);
        }

        if (!DateUtils.isSameDay(date, details.getSetTime())) {
            detailsAdj = calcTransitDetails(DateUtils.addHours(date, date.after(date) ? 23 : -23), location,
                    altitude);
            details.setSet((detailsAdj.getJulianSet().julian() - details.getReferenceTime().julian()) * 24);
        }

        assert DateUtils.isSameDay(details.getRiseTime(), details.getSetTime());
        return details;
    }

    protected JulianTransitDetails calcTransitDetails(Date date, Geolocation location, double altitude) {
        JulianDate jd = new JulianDate(date);
        EllipticalPlanetaryDetails aoDetails = Elliptical.calculate(jd.julian() - 1, this);
        double Alpha1 = aoDetails.ApparentGeocentricRA;
        double Delta1 = aoDetails.ApparentGeocentricDeclination;
        aoDetails = Elliptical.calculate(jd.julian(), this);
        double Alpha2 = aoDetails.ApparentGeocentricRA;
        double Delta2 = aoDetails.ApparentGeocentricDeclination;
        aoDetails = Elliptical.calculate(jd.julian() + 1, this);
        double Alpha3 = aoDetails.ApparentGeocentricRA;
        double Delta3 = aoDetails.ApparentGeocentricDeclination;

        return RiseTransitSet.calculate(jd.julian(), Alpha1, Delta1, Alpha2, Delta2, Alpha3, Delta3,
                location.getLongitude(Geolocation.Direction.WEST),
                location.getLatitude(Geolocation.Direction.NORTH), altitude);

    }
}