sunrise2.html

日出日落计算程序的网页源代码 从网络上搜索到的

		// *** Second pass includes fractional jday in gamma calc

		var newt = calcTimeJulianCent(calcJDFromJulianCent(t) + timeUTC/1440.0); 
		eqTime = calcEquationOfTime(newt);
		solarDec = calcSunDeclination(newt);
		hourAngle = calcHourAngleSunrise(latitude, solarDec);
		delta = longitude - radToDeg(hourAngle);
		timeDiff = 4 * delta;
		timeUTC = 720 + timeDiff - eqTime; // in minutes

		// alert("eqTime = " + eqTime + "\nsolarDec = " + solarDec + "\ntimeUTC = " + timeUTC);

		return timeUTC;
	}

//***********************************************************************/
//* Name:    calcSolNoonUTC								*/
//* Type:    Function									*/
//* Purpose: calculate the Universal Coordinated Time (UTC) of solar	*/
//*		noon for the given day at the given location on earth		*/
//* Arguments:										*/
//*   t : number of Julian centuries since J2000.0				*/
//*   longitude : longitude of observer in degrees				*/
//* Return value:										*/
//*   time in minutes from zero Z							*/
//***********************************************************************/

	function calcSolNoonUTC(t, longitude)
	{
		// First pass uses approximate solar noon to calculate eqtime
		var tnoon = calcTimeJulianCent(calcJDFromJulianCent(t) + longitude/360.0);
		var eqTime = calcEquationOfTime(tnoon);
		var solNoonUTC = 720 + (longitude * 4) - eqTime; // min

		var newt = calcTimeJulianCent(calcJDFromJulianCent(t) -0.5 + solNoonUTC/1440.0); 

		eqTime = calcEquationOfTime(newt);
		// var solarNoonDec = calcSunDeclination(newt);
		solNoonUTC = 720 + (longitude * 4) - eqTime; // min
		
		return solNoonUTC;
	}

//***********************************************************************/
//* Name:    calcSunsetUTC								*/
//* Type:    Function									*/
//* Purpose: calculate the Universal Coordinated Time (UTC) of sunset	*/
//*			for the given day at the given location on earth	*/
//* Arguments:										*/
//*   JD  : julian day									*/
//*   latitude : latitude of observer in degrees				*/
//*   longitude : longitude of observer in degrees				*/
//* Return value:										*/
//*   time in minutes from zero Z							*/
//***********************************************************************/

	function calcSunsetUTC(JD, latitude, longitude)
	{
		var t = calcTimeJulianCent(JD);

		// *** Find the time of solar noon at the location, and use
        //     that declination. This is better than start of the 
        //     Julian day

		var noonmin = calcSolNoonUTC(t, longitude);
		var tnoon = calcTimeJulianCent (JD+noonmin/1440.0);

		// First calculates sunrise and approx length of day

		var eqTime = calcEquationOfTime(tnoon);
		var solarDec = calcSunDeclination(tnoon);
		var hourAngle = calcHourAngleSunset(latitude, solarDec);

		var delta = longitude - radToDeg(hourAngle);
		var timeDiff = 4 * delta;
		var timeUTC = 720 + timeDiff - eqTime;

		// first pass used to include fractional day in gamma calc

		var newt = calcTimeJulianCent(calcJDFromJulianCent(t) + timeUTC/1440.0); 
		eqTime = calcEquationOfTime(newt);
		solarDec = calcSunDeclination(newt);
		hourAngle = calcHourAngleSunset(latitude, solarDec);

		delta = longitude - radToDeg(hourAngle);
		timeDiff = 4 * delta;
		timeUTC = 720 + timeDiff - eqTime; // in minutes

		return timeUTC;
	}


//*********************************************************************/

// Returns the decimal latitude from the degrees, minutes and seconds entered 
// into the form	

	function getLatitude(latLongForm)
	{
		var neg = 0;
		var strLatDeg = latLongForm["latDeg"].value;
		var degs = parseFloat(latLongForm["latDeg"].value);
		if (latLongForm["latDeg"].value.charAt(0) == '-') 
		{
			neg = 1;
		}

		if (strLatDeg.indexOf(".") != -1) 
		{
			latLongForm["latMin"].value = 0;
			latLongForm["latSec"].value = 0;
		}

		if(latLongForm["latMin"].value == "")
		{
			latLongForm["latMin"].value = 0;
		}
		if(latLongForm["latSec"].value == "")
		{
			latLongForm["latSec"].value = 0;
		}

		var mins = parseFloat(latLongForm["latMin"].value);

		var secs = parseFloat(latLongForm["latSec"].value);

		if(neg != 1)
		{
			var decLat = degs + (mins / 60) + (secs / 3600);
		} else if(neg == 1)
		{
			var decLat = degs - (mins / 60) - (secs / 3600);
		} else 
		{
			return -9999;
		}
		return decLat;
	}	


//*********************************************************************/

// Returns the decimal longitude from the degrees, minutes and seconds entered 
// into the form	

	function getLongitude(latLongForm)
	{
		var neg = 0;
		var strLonDeg = latLongForm["lonDeg"].value;
		var degs = parseFloat(latLongForm["lonDeg"].value);
		if (latLongForm["lonDeg"].value.charAt(0) == '-') 
		{
			neg = 1;
		}

		if (strLonDeg.indexOf(".") != -1) 
		{
			latLongForm["lonMin"].value = 0;
			latLongForm["lonSec"].value = 0;
		}

		if(latLongForm["lonMin"].value == "")
		{
			latLongForm["lonMin"].value = 0;
		}
		if(latLongForm["lonSec"].value == "")
		{
			latLongForm["lonSec"].value = 0;
		}

		var mins = parseFloat(latLongForm["lonMin"].value);
		var secs = parseFloat(latLongForm["lonSec"].value);
		var decLon = degs + (mins / 60) + (secs / 3600);

		if(neg != 1)
		{
			var decLon = degs + (mins / 60) + (secs / 3600);
		} else if(neg == 1)
		{
			var decLon = degs - (mins / 60) - (secs / 3600);
		} else 
		{
			return -9999;
		}
		return decLon;
	}	


//***********************************************************************/
//* Name:    findRecentSunrise							*/
//* Type:    Function									*/
//* Purpose: calculate the julian day of the most recent sunrise		*/
//*		starting from the given day at the given location on earth	*/
//* Arguments:										*/
//*   JD  : julian day									*/
//*   latitude : latitude of observer in degrees				*/
//*   longitude : longitude of observer in degrees				*/
//* Return value:										*/
//*   julian day of the most recent sunrise					*/
//***********************************************************************/

	function findRecentSunrise(jd, latitude, longitude)
	{
		var julianday = jd;

		var time = calcSunriseUTC(julianday, latitude, longitude);
		while(!isNumber(time)){
			julianday -= 1.0;
			time = calcSunriseUTC(julianday, latitude, longitude);
		}

		return julianday;
	}


//***********************************************************************/
//* Name:    findRecentSunset								*/
//* Type:    Function									*/
//* Purpose: calculate the julian day of the most recent sunset		*/
//*		starting from the given day at the given location on earth	*/
//* Arguments:										*/
//*   JD  : julian day									*/
//*   latitude : latitude of observer in degrees				*/
//*   longitude : longitude of observer in degrees				*/
//* Return value:										*/
//*   julian day of the most recent sunset					*/
//***********************************************************************/

	function findRecentSunset(jd, latitude, longitude)
	{
		var julianday = jd;

		var time = calcSunsetUTC(julianday, latitude, longitude);
		while(!isNumber(time)){
			julianday -= 1.0;
			time = calcSunsetUTC(julianday, latitude, longitude);
		}

		return julianday;
	}


//***********************************************************************/
//* Name:    findNextSunrise								*/
//* Type:    Function									*/
//* Purpose: calculate the julian day of the next sunrise			*/
//*		starting from the given day at the given location on earth	*/
//* Arguments:										*/
//*   JD  : julian day									*/
//*   latitude : latitude of observer in degrees				*/
//*   longitude : longitude of observer in degrees				*/
//* Return value:										*/
//*   julian day of the next sunrise						*/
//***********************************************************************/

	function findNextSunrise(jd, latitude, longitude)
	{
		var julianday = jd;

		var time = calcSunriseUTC(julianday, latitude, longitude);
		while(!isNumber(time)){
			julianday += 1.0;
			time = calcSunriseUTC(julianday, latitude, longitude);
		}

		return julianday;
	}


//***********************************************************************/
//* Name:    findNextSunset								*/
//* Type:    Function									*/
//* Purpose: calculate the julian day of the next sunset			*/
//*		starting from the given day at the given location on earth	*/
//* Arguments:										*/
//*   JD  : julian day									*/
//*   latitude : latitude of observer in degrees				*/
//*   longitude : longitude of observer in degrees				*/
//* Return value:										*/
//*   julian day of the next sunset							*/
//***********************************************************************/

	function findNextSunset(jd, latitude, longitude)
	{
		var julianday = jd;

		var time = calcSunsetUTC(julianday, latitude, longitude);
		while(!isNumber(time)){
			julianday += 1.0;
			time = calcSunsetUTC(julianday, latitude, longitude);
		}

		return julianday;
	}

//***********************************************************************/
//* Name:    timeString									*/
//* Type:    Function									*/
//* Purpose: convert time of day in minutes to a zero-padded string	*/
//*		suitable for printing to the form text fields			*/
//* Arguments:										*/
//*   minutes : time of day in minutes						*/
//* Return value:										*/
//*   string of the format HH:MM:SS, minutes and seconds are zero padded*/
//***********************************************************************/

	function timeString(minutes)
	// timeString returns a zero-padded string (HH:MM:SS) given time in minutes
	{
		var floatHour = minutes / 60.0;
		var hour = Math.floor(floatHour);
		var floatMinute = 60.0 * (floatHour - Math.floor(floatHour));
		var minute = Math.floor(floatMinute);
		var floatSec = 60.0 * (floatMinute - Math.floor(floatMinute));
		var second = Math.floor(floatSec + 0.5);

		var timeStr = hour + ":";
		if (minute < 10)	//	i.e. only one digit
			timeStr += "0" + minute + ":";
		else
			timeStr += minute + ":";
		if (second < 10)	//	i.e. only one digit
			timeStr += "0" + second;
		else
			timeStr += second;

		return timeStr;
	}


//***********************************************************************/
//* Name:    timeStringShortAMPM							*/
//* Type:    Function									*/
//* Purpose: convert time of day in minutes to a zero-padded string	*/
//*		suitable for printing to the form text fields.  If time	*/
//*		crosses a day boundary, date is appended.				*/
//* Arguments:										*/
//*   minutes : time of day in minutes						*/
//*   JD  : julian day									*/
//* Return value:										*/
//*   string of the format HH:MM[AM/PM] (DDMon)					*/
//***********************************************************************/

// timeStringShortAMPM returns a zero-padded string (HH:MM *M) given time in 
// minutes and appends short date if time is > 24 or < 0, resp.

	function timeStringShortAMPM(minutes, JD)
	{
		var julianday = JD;
		var floatHour = minutes / 60.0;
		var hour = Math.floor(floatHour);
		var floatMinute = 60.0 * (floatHour - Math.floor(floatHour));
		var minute = Math.floor(floatMinute);
		var floatSec = 60.0 * (floatMinute - Math.floor(floatMinute));
		var second = Math.floor(floatSec + 0.5);
		var PM = false;

		minute += (second >= 30)? 1 : 0;

		if (minute >= 60) 
		{
			minute -= 60;
			hour ++;
		}

		var daychange = false;
		if (hour > 23) 
		{
			hour -= 24;
			daychange = true;
			julianday += 1.0;
		}

		if (hour < 0)
		{
			hour += 24;
			daychange = true;
			julianday -= 1.0;
		}

		if (hour > 12)
		{
			hour -= 12;
			PM = true;
		}

            if (hour == 12)
		{
              PM = true;