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package ru.olamedia.astronomy;
/*
* Copyright 2011 Brad Parks
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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.
*/
//package com.bradsbrain.simpleastronomy;
import java.util.Calendar;
/**
* Heavily based on procedures as documented in the book
* "Practical Astronomy with Your Calculator", 3rd Edition, by Peter
* Duffett-Smith, Cambridge University Press, 1988, 1990, 1992
*
* @author bradparks
*/
public class JulianDate {
/**
* This method is a simplification of formula in Section 3 of PAwyC3. We'll
* assume we're only talking about Gregorian Calendar dates because really,
* we don't care a whole lot about past dates.
*
* @param cal
* @return
*/
public static double makeJulianDateUsingMyModified(Calendar cal) {
Calendar myCal = BaseUtils.getSafeLocalCopy(cal.getTimeInMillis());
// step 1
int year = myCal.get(Calendar.YEAR);
int month = myCal.get(Calendar.MONTH) + 1; // fix the January=0
double day = myCal.get(Calendar.DAY_OF_MONTH);
double hour = myCal.get(Calendar.HOUR_OF_DAY) / 24.0;
double minute = myCal.get(Calendar.MINUTE) / 24.0 / 60.0;
double second = myCal.get(Calendar.SECOND) / 24.0 / 60.0 / 60.0;
// step 2
if (month <= 2) {
year--;
month += 12;
}
// step 6
return 1720995.5 + Math.floor(365.243 * year)
+ Math.floor(30.6 * ++month) + day + hour + minute + second;
}
}
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