NOAA Improved Sunrise/Sunset Calculation

<HTML> <HEAD> <TITLE>NOAA Improved Sunrise/Sunset Calculation</TITLE> <SCRIPT LANGUAGE="JavaScript"> //***********************************************************************/ //* DATA STRUCTURES */ //***********************************************************************/ function month(name, numdays, abbr) { this.name = name; this.numdays = numdays; this.abbr = abbr; } //*********************************************************************/ function ans(daySave,value) { this.daySave = daySave; this.value = value; } //*********************************************************************/ function city(name, lat, lng, zoneHr) { this.name = name; this.lat = lat; this.lng = lng; this.zoneHr = zoneHr; } //***********************************************************************/ //* Data for Selectbox Controls */ //***********************************************************************/ var monthList = new Array(); // list of months and days for non-leap year var i = 0; monthList[i++] = new month("January", 31, "Jan"); monthList[i++] = new month("February", 28, "Feb"); monthList[i++] = new month("March", 31, "Mar"); monthList[i++] = new month("April", 30, "Apr"); monthList[i++] = new month("May", 31, "May"); monthList[i++] = new month("June", 30, "Jun"); monthList[i++] = new month("July", 31, "Jul"); monthList[i++] = new month("August", 31, "Aug"); monthList[i++] = new month("September", 30, "Sep"); monthList[i++] = new month("October", 31, "Oct"); monthList[i++] = new month("November", 30, "Nov"); monthList[i++] = new month("December", 31, "Dec"); //*********************************************************************/ var YesNo = new Array(); //Daylight Saving array i=0; YesNo[i++] = new ans("No",0); YesNo[i++] = new ans("Yes",60); //*********************************************************************/ var City = new Array(); j = 0; City[j++] = new city("Enter Lat/Long -->",0,0,0); City[j++] = new city("",0,0,0); City[j++] = new city("US CITIES",0,0,0); City[j++] = new city("Albuquerque, NM", 35.0833,106.65,7); City[j++] = new city("Anchorage, AK", 61.217, 149.90,9); City[j++] = new city("Atlanta, GA", 33.733, 84.383, 5); City[j++] = new city("Austin, TX", 30.283, 97.733, 6); City[j++] = new city("Birmingham, AL", 33.521, 86.8025, 6); City[j++] = new city("Bismarck, ND", 46.817, 100.783, 6); City[j++] = new city("Boston, MA", 42.35, 71.05, 5); City[j++] = new city("Boulder, CO", 40.125, 105.237, 7); City[j++] = new city("Chicago, IL", 41.85,87.65,6); City[j++] = new city("Dallas, TX", 32.46, 96.47,6); City[j++] = new city("Denver, CO", 39.733, 104.983, 7); City[j++] = new city("Detroit, MI", 42.333, 83.05, 5); City[j++] = new city("Honolulu, HI", 21.30, 157.85, 10); City[j++] = new city("Houston, TX", 29.75, 95.35, 6); City[j++] = new city("Indianapolis, IN", 39.767, 86.15, 5); City[j++] = new city("Jackson, MS", 32.283, 90.183, 6); City[j++] = new city("Kansas City, MO", 39.083, 94.567,6); City[j++] = new city("Los Angeles, CA",34.05,118.233,8); City[j++] = new city("Menomonee Falls, WI",43.11,88.10,6); City[j++] = new city("Miami, FL", 25.767, 80.183,5); City[j++] = new city("Minneapolis, MN", 44.967, 93.25, 6); City[j++] = new city("New Orleans, LA", 29.95, 90.067, 6); City[j++] = new city("New York City, NY", 40.7167, 74.0167, 5); City[j++] = new city("Oklahoma City, OK", 35.483, 97.533,6); City[j++] = new city("Philadelphia, PA", 39.95, 75.15, 5); City[j++] = new city("Phoenix, AZ",33.433,112.067,7); City[j++] = new city("Pittsburgh, PA",40.433,79.9833,5); City[j++] = new city("Portland, ME", 43.666, 70.283, 5); City[j++] = new city("Portland, OR", 45.517, 122.65, 8); City[j++] = new city("Raleigh, NC", 35.783, 78.65, 5); City[j++] = new city("Richmond, VA", 37.5667, 77.450, 5); City[j++] = new city("Saint Louis, MO", 38.6167,90.1833,6); City[j++] = new city("San Antonio, TX", 29.53, 98.47, 6); City[j++] = new city("San Diego, CA", 32.7667, 117.2167, 8); City[j++] = new city("San Francisco, CA",37.7667,122.4167,8); City[j++] = new city("Seattle, WA",47.60,122.3167,8); City[j++] = new city("Washington DC", 38.8833, 77.0333,5); City[j++] = new city("",0,0,0); City[j++] = new city("WORLD CITIES",0,0,0); City[j++] = new city("Beijing, China",39.9167, -116.4167,-8); City[j++] = new city("Berlin, Germany",52.33, -13.30, -1); City[j++] = new city("Bombay, India", 18.9333, -72.8333, -5.5); City[j++] = new city("Buenos Aires, Argentina", -34.60,58.45,3); City[j++] = new city("Cairo, Egypt", 30.10,-31.3667,-2); City[j++] = new city("Cape Town, South Africa",-33.9167,-18.3667,-2); City[j++] = new city("Caracas, Venezuela", 10.50,66.9333,4); City[j++] = new city("Helsinki, Finland", 60.1667, -24.9667,-2); City[j++] = new city("Hong Kong, China", 22.25,-114.1667, -8); City[j++] = new city("Jerusalem, Israel", 31.7833, -35.2333, -2); City[j++] = new city("London, England", 51.50, 0.1667,0); City[j++] = new city("Mexico City, Mexico", 19.4,99.15,6); City[j++] = new city("Moscow, Russia", 55.75, -37.5833, -3); City[j++] = new city("New Delhi, India",28.6, -77.2, -5.5); City[j++] = new city("Ottawa, Canada", 45.41667,75.7,5); City[j++] = new city("Paris, France", 48.8667, -2.667, -1); City[j++] = new city("Rio de Janeiro, Brazil",-22.90,43.2333,3); City[j++] = new city("Riyadh, Saudi Arabia", 24.633, -46.71667, -3); City[j++] = new city("Rome, Italy",41.90, -12.4833,-1); City[j++] = new city("Sydney, Australia",-33.8667,-151.2167,-10); City[j++] = new city("Tokyo, Japan", 35.70, -139.7667, -9); City[j++] = new city("Zurich, Switzerland", 47.3833, -8.5333,-1); City[j++] = new city("",0,0,0); City[j++] = new city("SURFRAD NETWORK",0,0,0); City[j++] = new city("Goodwin Creek, MS",34.2544444,89.8738888, 6); City[j++] = new city("Fort Peck, MT",48.310555,105.1025, 7); City[j++] = new city("Bondville, IL",40.055277,88.371944, 6); City[j++] = new city("Table Mountain, CO",40.125,105.23694, 7); City[j++] = new city("Desert Rock, NV",36.626, 116.018, 8); City[j++] = new city("Penn State, PA", 40.72, 77.93, 5); City[j++] = new city("Canaan Valley, WV", 39.1, 79.4, 5); City[j++] = new city("Sioux Falls, SD", 43.733, 96.6233, 6); City[j++] = new city("",0,0,0); City[j++] = new city("ARM/CART NETWORK",0,0,0); City[j++] = new city("Atqasuk, AK", 70.47215, 157.4078, 9); City[j++] = new city("Barrow, AK", 71.30,156.683, 9); City[j++] = new city("Manus Island, PNG", -2.06, -147.425,-10); City[j++] = new city("Nauru Island", -0.52, -166.92, -12); City[j++] = new city("Darwin, Australia", -12.425, -130.891, -9.5); City[j++] = new city("SGP Central Facility", 36.6167, 97.5, 6); City[j++] = new city("",0,0,0); City[j++] = new city("SOLRAD NETWORK",0,0,0); City[j++] = new city("Albuquerque, NM", 35.04, 106.62,7); City[j++] = new city("Bismarck, ND", 46.77, 100.77,6); City[j++] = new city("Hanford, CA", 36.31, 119.63,8); City[j++] = new city("Madison, WI", 43.13, 89.33,6); City[j++] = new city("Oak Ridge, TN", 35.96, 84.37,5); City[j++] = new city("Salt Lake City, UT", 40.77,111.97,7); City[j++] = new city("Seattle, WA", 47.68, 122.25,8); City[j++] = new city("Sterling, VA", 38.98, 77.47,5); City[j++] = new city("Tallahassee, FL", 30.38, 84.37,5); //*********************************************************************/ </SCRIPT> </HEAD> <BODY BACKGROUND="./hasunset1.jpg" bgcolor="#99CCFF"> <CENTER> <TABLE BORDER=0 CELLPADDING=5> <TR><TD> <A HREF="http://www.doc.gov"><IMG SRC="./doclogo.gif" ALT="Dept of Commerce Seal" BORDER=0></A> </TD> <TD> <CENTER> <FONT SIZE="4"><B><A HREF="/index.html">NOAA GMl</A></B></FONT><BR> <FONT SIZE="6"><B>Sunrise/Sunset Calculator</B></FONT> </CENTER> </TD> <TD> <CENTER> <A HREF="http://www.noaa.gov"><IMG SRC="./noaaemblemt.gif" ALT="National Oceanic and Atmospheric Administration" BORDER=0></A><BR> <A HREF="http://www.esrl.noaa.gov"><FONT SIZE="2">Earth System<br>Research Lab</FONT></A> </CENTER> </TD> </TR> </TABLE> </CENTER> <p>Please note that this web page is the old version of the NOAA Solar Calculator. Back when this calculator was first created, we decided to use a non-standard definition of longitude and time zone, to make coordinate entry less awkward. So on this page, both longitude and time zone are defined as positive to the west, instead of the international standard of positive to the east of the Prime Meridian. <p>We maintain this page as a courtesy to those people who, for whatever reason, prefer the old calculator. For the rest of you, we encourage you to instead <A HREF="http://gml.noaa.gov/grad/solcalc/">click here to try the updated version of NOAA's Solar Calculator</A> <HR> <SCRIPT LANGUAGE="JavaScript"> //*********************************************************************/ function setLatLong(f, index) { // Decimal degrees are passed in the array. Temporarily store these // degs in lat and lon deg and have convLatLong modify them. f["latDeg"].value = City[index].lat; f["lonDeg"].value = City[index].lng; // These are needed to prevent iterative adding of min and sec when // set button is clicked. f["latMin"].value = 0; f["latSec"].value = 0; f["lonMin"].value = 0; f["lonSec"].value = 0; //call convLatLong to convert decimal degrees into table form. convLatLong(f); //Local time zone value set in table f["hrsToGMT"].value = City[index].zoneHr; } //*********************************************************************/ // isLeapYear returns 1 if the 4-digit yr is a leap year, 0 if it is not function isLeapYear(yr) { return ((yr % 4 == 0 && yr % 100 != 0) || yr % 400 == 0); } //*********************************************************************/ // isPosInteger returns false if the value is not a positive integer, true is // returned otherwise. The code is from taken from Danny Goodman's Javascript // Handbook, p. 372. function isPosInteger(inputVal) { inputStr = ("" + inputVal); for (var i = 0; i < inputStr.length; i++) { var oneChar = inputStr.charAt(i); if (oneChar < "0" || oneChar > "9") return false; } return true; } //*********************************************************************/ function isInteger(inputVal) { inputStr = "" + inputVal; if(inputStr == "NaN") return false; if(inputStr == "-NaN") return false; for (var i = 0; i < inputStr.length; i++) { var oneChar = inputStr.charAt(i); if (i == 0 && (oneChar == "-" || oneChar == "+")) { continue; } if (oneChar < "0" || oneChar > "9") { return false; } } return true; } //*********************************************************************/ function isNumber(inputVal) { var oneDecimal = false; var inputStr = "" + inputVal; for (var i = 0; i < inputStr.length; i++) { var oneChar = inputStr.charAt(i); if (i == 0 && (oneChar == "-" || oneChar == "+")) { continue; } if (oneChar == "." && !oneDecimal) { oneDecimal = true; continue; } if (oneChar < "0" || oneChar > "9") { return false; } } return true; } //*********************************************************************/ // isValidInput makes sure valid input is entered before going ahead to // calculate the sunrise and sunset. False is returned if an invalid entry // was made, true is the entry is valid. function isValidInput(f, index, latLongForm) { if (f["day"].value == "") { // see if the day field is empty alert("You must enter a day before attempting the calculation."); return false; } else if (f["year"].value == "") { // see if the year field is empty alert("You must enter a year before attempting the calculation."); return false; } else if (!isPosInteger(f["day"].value) || f["day"].value == 0) { alert("The day must be a positive integer."); return false; } else if (!isInteger(f["year"].value)) { alert("The year must be an integer."); return false; } else if ( (f["year"].value < -1000) || (f["year"].value > 3000) ) { alert("The algorithm used is not valid for years outside of/nthe range -1000 to 3000."); return false; } // For the non-February months see if the day entered is greater than // the number of days in the selected month else if ((index != 1) && (f["day"].value > monthList[index].numdays)) { alert("There are only " + monthList[index].numdays + " days in " + monthList[index].name + "."); return false; } // First see if the year entered is a leap year. If so we have to make sure // the days entered is <= 29. If not a leap year we make sure that the days // entered is <= 28. else if (index == 1) { // month selected is February the screwball month if (isLeapYear(f["year"].value)) { // year entered is a leap year if (f["day"].value > (monthList[index].numdays + 1)) { alert("There are only " + (monthList[index].numdays + 1) + " days in " + monthList[index].name + "."); return false; } else return true; } else { // year entered is not a leap year if (f["day"].value > monthList[index].numdays) { alert("There are only " + monthList[index].numdays + " days in " + monthList[index].name + "."); return false; } else return true; } } else return true; } //*********************************************************************/ //convLatLong converts any type of lat/long input //into the table form and then handles bad input //it is nested in the calcSun function. function convLatLong(f) { if(f["latDeg"].value == "") { f["latDeg"].value = 0; } if(f["latMin"].value == "") { f["latMin"].value = 0; } if(f["latSec"].value == "") { f["latSec"].value = 0; } if(f["lonDeg"].value == "") { f["lonDeg"].value = 0; } if(f["lonMin"].value == "") { f["lonMin"].value = 0; } if(f["lonSec"].value == "") { f["lonSec"].value = 0; } var neg = 0; if(f["latDeg"].value.charAt(0) == '-') { neg = 1; } if(neg != 1) { var latSeconds = (parseFloat(f["latDeg"].value))*3600 + parseFloat(f["latMin"].value)*60 + parseFloat(f["latSec"].value)*1; f["latDeg"].value = Math.floor(latSeconds/3600); f["latMin"].value = Math.floor((latSeconds - (parseFloat(f["latDeg"].value)*3600))/60); f["latSec"].value = Math.floor((latSeconds - (parseFloat(f["latDeg"].value)*3600) - (parseFloat(f["latMin"].value)*60)) + 0.5); } else if(parseFloat(f["latDeg"].value) > -1) { var latSeconds = parseFloat(f["latDeg"].value)*3600 - parseFloat(f["latMin"].value)*60 - parseFloat(f["latSec"].value)*1; f["latDeg"].value = "-0"; f["latMin"].value = Math.floor((-latSeconds)/60); f["latSec"].value = Math.floor( (-latSeconds - (parseFloat(f["latMin"].value)*60)) + 0.5); } else { var latSeconds = parseFloat(f["latDeg"].value)*3600 - parseFloat(f["latMin"].value)*60 - parseFloat(f["latSec"].value)*1; f["latDeg"].value = Math.ceil(latSeconds/3600); f["latMin"].value = Math.floor((-latSeconds + (parseFloat(f["latDeg"].value)*3600))/60); f["latSec"].value = Math.floor((-latSeconds + (parseFloat(f["latDeg"].value)*3600) - (parseFloat(f["latMin"].value)*60)) + 0.5); } neg = 0; if(f["lonDeg"].value.charAt(0) == '-') { neg = 1; } if(neg != 1) { var lonSeconds = parseFloat(f["lonDeg"].value)*3600 + parseFloat(f["lonMin"].value)*60 + parseFloat(f["lonSec"].value)*1; f["lonDeg"].value = Math.floor(lonSeconds/3600); f["lonMin"].value = Math.floor((lonSeconds - (parseFloat(f["lonDeg"].value)*3600))/60); f["lonSec"].value = Math.floor((lonSeconds - (parseFloat(f["lonDeg"].value)*3600) - (parseFloat(f["lonMin"].value))*60) + 0.5); } else if(parseFloat(f["lonDeg"].value) > -1) { var lonSeconds = parseFloat(f["lonDeg"].value)*3600 - parseFloat(f["lonMin"].value)*60 - parseFloat(f["lonSec"].value)*1; f["lonDeg"].value = "-0"; f["lonMin"].value = Math.floor((-lonSeconds)/60); f["lonSec"].value = Math.floor((-lonSeconds - (parseFloat(f["lonMin"].value)*60)) + 0.5); } else { var lonSeconds = parseFloat(f["lonDeg"].value)*3600 - parseFloat(f["lonMin"].value)*60 - parseFloat(f["lonSec"].value)*1; f["lonDeg"].value = Math.ceil(lonSeconds/3600); f["lonMin"].value = Math.floor((-lonSeconds + (parseFloat(f["lonDeg"].value)*3600))/60); f["lonSec"].value = Math.floor((-lonSeconds + (parseFloat(f["lonDeg"].value)*3600) - (parseFloat(f["lonMin"].value)*60)) + 0.5); } //Test for invalid lat/long input if(latSeconds > 324000) { alert("You have entered an invalid latitude.\n Setting lat = 89."); f["latDeg"].value = 89; f["latMin"].value = 0; f["latSec"].value = 0; } if(latSeconds < -324000) { alert("You have entered an invalid latitude.\n Setting lat = -89."); f["latDeg"].value = -89; f["latMin"].value = 0; f["latSec"].value = 0; } if(lonSeconds > 648000) { alert("You have entered an invalid longitude.\n Setting lon = 180."); f["lonDeg"].value = 180; f["lonMin"].value = 0; f["lonSec"].value = 0; } if(lonSeconds < -648000) { alert("You have entered an invalid longitude.\n Setting lon = -180."); f["lonDeg"].value = -180; f["lonMin"].value = 0; f["lonSec"].value =0; } } //***********************************************************************/ //***********************************************************************/ //* */ //*This section contains subroutines used in calculating solar position */ //* */ //***********************************************************************/ //***********************************************************************/ // Convert radian angle to degrees function radToDeg(angleRad) { return (180.0 * angleRad / Math.PI); } //*********************************************************************/ // Convert degree angle to radians function degToRad(angleDeg) { return (Math.PI * angleDeg / 180.0); } //*********************************************************************/ //***********************************************************************/ //* Name: calcDayOfYear */ //* Type: Function */ //* Purpose: Finds numerical day-of-year from mn, day and lp year info */ //* Arguments: */ //* month: January = 1 */ //* day : 1 - 31 */ //* lpyr : 1 if leap year, 0 if not */ //* Return value: */ //* The numerical day of year */ //***********************************************************************/ function calcDayOfYear(mn, dy, lpyr) { var k = (lpyr ? 1 : 2); var doy = Math.floor((275 * mn)/9) - k * Math.floor((mn + 9)/12) + dy -30; return doy; } //***********************************************************************/ //* Name: calcDayOfWeek */ //* Type: Function */ //* Purpose: Derives weekday from Julian Day */ //* Arguments: */ //* juld : Julian Day */ //* Return value: */ //* String containing name of weekday */ //***********************************************************************/ function calcDayOfWeek(juld) { var A = (juld + 1.5) % 7; var DOW = (A==0)?"Sunday":(A==1)?"Monday":(A==2)?"Tuesday":(A==3)?"Wednesday":(A==4)?"Thursday":(A==5)?"Friday":"Saturday"; return DOW; } //***********************************************************************/ //* Name: calcJD */ //* Type: Function */ //* Purpose: Julian day from calendar day */ //* Arguments: */ //* year : 4 digit year */ //* month: January = 1 */ //* day : 1 - 31 */ //* Return value: */ //* The Julian day corresponding to the date */ //* Note: */ //* Number is returned for start of day. Fractional days should be */ //* added later. */ //***********************************************************************/ function calcJD(year, month, day) { if (month <= 2) { year -= 1; month += 12; } var A = Math.floor(year/100); var B = 2 - A + Math.floor(A/4); var JD = Math.floor(365.25*(year + 4716)) + Math.floor(30.6001*(month+1)) + day + B - 1524.5; return JD; } //***********************************************************************/ //* Name: calcDateFromJD */ //* Type: Function */ //* Purpose: Calendar date from Julian Day */ //* Arguments: */ //* jd : Julian Day */ //* Return value: */ //* String date in the form DD-MONTHNAME-YYYY */ //* Note: */ //***********************************************************************/ function calcDateFromJD(jd) { var z = Math.floor(jd + 0.5); var f = (jd + 0.5) - z; if (z < 2299161) { var A = z; } else { alpha = Math.floor((z - 1867216.25)/36524.25); var A = z + 1 + alpha - Math.floor(alpha/4); } var B = A + 1524; var C = Math.floor((B - 122.1)/365.25); var D = Math.floor(365.25 * C); var E = Math.floor((B - D)/30.6001); var day = B - D - Math.floor(30.6001 * E) + f; var month = (E < 14) ? E - 1 : E - 13; var year = (month > 2) ? C - 4716 : C - 4715; // alert ("date: " + day + "-" + monthList[month-1].name + "-" + year); return (day + "-" + monthList[month-1].name + "-" + year); } //***********************************************************************/ //* Name: calcDayFromJD */ //* Type: Function */ //* Purpose: Calendar day (minus year) from Julian Day */ //* Arguments: */ //* jd : Julian Day */ //* Return value: */ //* String date in the form DD-MONTH */ //***********************************************************************/ function calcDayFromJD(jd) { var z = Math.floor(jd + 0.5); var f = (jd + 0.5) - z; if (z < 2299161) { var A = z; } else { alpha = Math.floor((z - 1867216.25)/36524.25); var A = z + 1 + alpha - Math.floor(alpha/4); } var B = A + 1524; var C = Math.floor((B - 122.1)/365.25); var D = Math.floor(365.25 * C); var E = Math.floor((B - D)/30.6001); var day = B - D - Math.floor(30.6001 * E) + f; var month = (E < 14) ? E - 1 : E - 13; var year = (month > 2) ? C - 4716 : C - 4715; return ((day<10 ? "0" : "") + day + monthList[month-1].abbr); } //***********************************************************************/ //* Name: calcTimeJulianCent */ //* Type: Function */ //* Purpose: convert Julian Day to centuries since J2000.0. */ //* Arguments: */ //* jd : the Julian Day to convert */ //* Return value: */ //* the T value corresponding to the Julian Day */ //***********************************************************************/ function calcTimeJulianCent(jd) { var T = (jd - 2451545.0)/36525.0; return T; } //***********************************************************************/ //* Name: calcJDFromJulianCent */ //* Type: Function */ //* Purpose: convert centuries since J2000.0 to Julian Day. */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* the Julian Day corresponding to the t value */ //***********************************************************************/ function calcJDFromJulianCent(t) { var JD = t * 36525.0 + 2451545.0; return JD; } //***********************************************************************/ //* Name: calGeomMeanLongSun */ //* Type: Function */ //* Purpose: calculate the Geometric Mean Longitude of the Sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* the Geometric Mean Longitude of the Sun in degrees */ //***********************************************************************/ function calcGeomMeanLongSun(t) { var L0 = 280.46646 + t * (36000.76983 + 0.0003032 * t); while(L0 > 360.0) { L0 -= 360.0; } while(L0 < 0.0) { L0 += 360.0; } return L0; // in degrees } //***********************************************************************/ //* Name: calGeomAnomalySun */ //* Type: Function */ //* Purpose: calculate the Geometric Mean Anomaly of the Sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* the Geometric Mean Anomaly of the Sun in degrees */ //***********************************************************************/ function calcGeomMeanAnomalySun(t) { var M = 357.52911 + t * (35999.05029 - 0.0001537 * t); return M; // in degrees } //***********************************************************************/ //* Name: calcEccentricityEarthOrbit */ //* Type: Function */ //* Purpose: calculate the eccentricity of earth's orbit */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* the unitless eccentricity */ //***********************************************************************/ function calcEccentricityEarthOrbit(t) { var e = 0.016708634 - t * (0.000042037 + 0.0000001267 * t); return e; // unitless } //***********************************************************************/ //* Name: calcSunEqOfCenter */ //* Type: Function */ //* Purpose: calculate the equation of center for the sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* in degrees */ //***********************************************************************/ function calcSunEqOfCenter(t) { var m = calcGeomMeanAnomalySun(t); var mrad = degToRad(m); var sinm = Math.sin(mrad); var sin2m = Math.sin(mrad+mrad); var sin3m = Math.sin(mrad+mrad+mrad); var C = sinm * (1.914602 - t * (0.004817 + 0.000014 * t)) + sin2m * (0.019993 - 0.000101 * t) + sin3m * 0.000289; return C; // in degrees } //***********************************************************************/ //* Name: calcSunTrueLong */ //* Type: Function */ //* Purpose: calculate the true longitude of the sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* sun's true longitude in degrees */ //***********************************************************************/ function calcSunTrueLong(t) { var l0 = calcGeomMeanLongSun(t); var c = calcSunEqOfCenter(t); var O = l0 + c; return O; // in degrees } //***********************************************************************/ //* Name: calcSunTrueAnomaly */ //* Type: Function */ //* Purpose: calculate the true anamoly of the sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* sun's true anamoly in degrees */ //***********************************************************************/ function calcSunTrueAnomaly(t) { var m = calcGeomMeanAnomalySun(t); var c = calcSunEqOfCenter(t); var v = m + c; return v; // in degrees } //***********************************************************************/ //* Name: calcSunRadVector */ //* Type: Function */ //* Purpose: calculate the distance to the sun in AU */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* sun radius vector in AUs */ //***********************************************************************/ function calcSunRadVector(t) { var v = calcSunTrueAnomaly(t); var e = calcEccentricityEarthOrbit(t); var R = (1.000001018 * (1 - e * e)) / (1 + e * Math.cos(degToRad(v))); return R; // in AUs } //***********************************************************************/ //* Name: calcSunApparentLong */ //* Type: Function */ //* Purpose: calculate the apparent longitude of the sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* sun's apparent longitude in degrees */ //***********************************************************************/ function calcSunApparentLong(t) { var o = calcSunTrueLong(t); var omega = 125.04 - 1934.136 * t; var lambda = o - 0.00569 - 0.00478 * Math.sin(degToRad(omega)); return lambda; // in degrees } //***********************************************************************/ //* Name: calcMeanObliquityOfEcliptic */ //* Type: Function */ //* Purpose: calculate the mean obliquity of the ecliptic */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* mean obliquity in degrees */ //***********************************************************************/ function calcMeanObliquityOfEcliptic(t) { var seconds = 21.448 - t*(46.8150 + t*(0.00059 - t*(0.001813))); var e0 = 23.0 + (26.0 + (seconds/60.0))/60.0; return e0; // in degrees } //***********************************************************************/ //* Name: calcObliquityCorrection */ //* Type: Function */ //* Purpose: calculate the corrected obliquity of the ecliptic */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* corrected obliquity in degrees */ //***********************************************************************/ function calcObliquityCorrection(t) { var e0 = calcMeanObliquityOfEcliptic(t); var omega = 125.04 - 1934.136 * t; var e = e0 + 0.00256 * Math.cos(degToRad(omega)); return e; // in degrees } //***********************************************************************/ //* Name: calcSunRtAscension */ //* Type: Function */ //* Purpose: calculate the right ascension of the sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* sun's right ascension in degrees */ //***********************************************************************/ function calcSunRtAscension(t) { var e = calcObliquityCorrection(t); var lambda = calcSunApparentLong(t); var tananum = (Math.cos(degToRad(e)) * Math.sin(degToRad(lambda))); var tanadenom = (Math.cos(degToRad(lambda))); var alpha = radToDeg(Math.atan2(tananum, tanadenom)); return alpha; // in degrees } //***********************************************************************/ //* Name: calcSunDeclination */ //* Type: Function */ //* Purpose: calculate the declination of the sun */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* sun's declination in degrees */ //***********************************************************************/ function calcSunDeclination(t) { var e = calcObliquityCorrection(t); var lambda = calcSunApparentLong(t); var sint = Math.sin(degToRad(e)) * Math.sin(degToRad(lambda)); var theta = radToDeg(Math.asin(sint)); return theta; // in degrees } //***********************************************************************/ //* Name: calcEquationOfTime */ //* Type: Function */ //* Purpose: calculate the difference between true solar time and mean */ //* solar time */ //* Arguments: */ //* t : number of Julian centuries since J2000.0 */ //* Return value: */ //* equation of time in minutes of time */ //***********************************************************************/ function calcEquationOfTime(t) { var epsilon = calcObliquityCorrection(t); var l0 = calcGeomMeanLongSun(t); var e = calcEccentricityEarthOrbit(t); var m = calcGeomMeanAnomalySun(t); var y = Math.tan(degToRad(epsilon)/2.0); y *= y; var sin2l0 = Math.sin(2.0 * degToRad(l0)); var sinm = Math.sin(degToRad(m)); var cos2l0 = Math.cos(2.0 * degToRad(l0)); var sin4l0 = Math.sin(4.0 * degToRad(l0)); var sin2m = Math.sin(2.0 * degToRad(m)); var Etime = y * sin2l0 - 2.0 * e * sinm + 4.0 * e * y * sinm * cos2l0 - 0.5 * y * y * sin4l0 - 1.25 * e * e * sin2m; return radToDeg(Etime)*4.0; // in minutes of time } //***********************************************************************/ //* Name: calcHourAngleSunrise */ //* Type: Function */ //* Purpose: calculate the hour angle of the sun at sunrise for the */ //* latitude */ //* Arguments: */ //* lat : latitude of observer in degrees */ //* solarDec : declination angle of sun in degrees */ //* Return value: */ //* hour angle of sunrise in radians */ //***********************************************************************/ function calcHourAngleSunrise(lat, solarDec) { var latRad = degToRad(lat); var sdRad = degToRad(solarDec) var HAarg = (Math.cos(degToRad(90.833))/(Math.cos(latRad)*Math.cos(sdRad))-Math.tan(latRad) * Math.tan(sdRad)); var HA = (Math.acos(Math.cos(degToRad(90.833))/(Math.cos(latRad)*Math.cos(sdRad))-Math.tan(latRad) * Math.tan(sdRad))); return HA; // in radians } //***********************************************************************/ //* Name: calcHourAngleSunset */ //* Type: Function */ //* Purpose: calculate the hour angle of the sun at sunset for the */ //* latitude */ //* Arguments: */ //* lat : latitude of observer in degrees */ //* solarDec : declination angle of sun in degrees */ //* Return value: */ //* hour angle of sunset in radians */ //***********************************************************************/ function calcHourAngleSunset(lat, solarDec) { var latRad = degToRad(lat); var sdRad = degToRad(solarDec) var HAarg = (Math.cos(degToRad(90.833))/(Math.cos(latRad)*Math.cos(sdRad))-Math.tan(latRad) * Math.tan(sdRad)); var HA = (Math.acos(Math.cos(degToRad(90.833))/(Math.cos(latRad)*Math.cos(sdRad))-Math.tan(latRad) * Math.tan(sdRad))); return -HA; // in radians } //***********************************************************************/ //* Name: calcSunriseUTC */ //* Type: Function */ //* Purpose: calculate the Universal Coordinated Time (UTC) of sunrise */ //* 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 calcSunriseUTC(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 pass to approximate sunrise (using solar noon) var eqTime = calcEquationOfTime(tnoon); var solarDec = calcSunDeclination(tnoon); var hourAngle = calcHourAngleSunrise(latitude, solarDec); var delta = longitude - radToDeg(hourAngle); var timeDiff = 4 * delta; // in minutes of time var timeUTC = 720 + timeDiff - eqTime; // in minutes // alert("eqTime = " + eqTime + "\nsolarDec = " + solarDec + "\ntimeUTC = " + timeUTC); // *** 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); if (second > 59) { second = 0; minute += 1; } 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; } if (hour == 0) { PM = false; hour = 12; } var timeStr = hour + ":"; if (minute < 10) // i.e. only one digit timeStr += "0" + minute + ((PM)?"PM":"AM"); else timeStr += "" + minute + ((PM)?"PM":"AM"); if (daychange) return timeStr + " " + calcDayFromJD(julianday); return timeStr; } //***********************************************************************/ //* Name: timeStringAMPMDate */ //* Type: Function */ //* Purpose: convert time of day in minutes to a zero-padded string */ //* suitable for printing to the form text fields, and appends */ //* the date. */ //* Arguments: */ //* minutes : time of day in minutes */ //* JD : julian day */ //* Return value: */ //* string of the format HH:MM[AM/PM] DDMon */ //***********************************************************************/ // timeStringAMPMDate returns a zero-padded string (HH:MM[AM/PM]) given time // in minutes and julian day, and appends the short date function timeStringAMPMDate(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); minute += (second >= 30)? 1 : 0; if (minute >= 60) { minute -= 60; hour ++; } if (hour > 23) { hour -= 24; julianday += 1.0; } if (hour < 0) { hour += 24; julianday -= 1.0; } var PM = false; if (hour > 12) { hour -= 12; PM = true; } if (hour == 12) { PM = true; } if (hour == 0) { PM = false; hour = 12; } var timeStr = hour + ":"; if (minute < 10) // i.e. only one digit timeStr += "0" + minute + ((PM)?"PM":"AM"); else timeStr += minute + ((PM)?"PM":"AM"); return timeStr + " " + calcDayFromJD(julianday); } //***********************************************************************/ //* Name: timeStringDate */ //* Type: Function */ //* Purpose: convert time of day in minutes to a zero-padded 24hr time */ //* 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 (DDMon) */ //***********************************************************************/ // timeStringDate returns a zero-padded string (HH:MM) given time in minutes // and julian day, and appends the short date if time crosses a day boundary function timeStringDate(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); minute += (second >= 30)? 1 : 0; if (minute >= 60) { minute -= 60; hour ++; } var daychange = false; if (hour > 23) { hour -= 24; julianday += 1.0; daychange = true; } if (hour < 0) { hour += 24; julianday -= 1.0; daychange = true; } var timeStr = hour + ":"; if (minute < 10) // i.e. only one digit timeStr += "0" + minute; else timeStr += minute; if (daychange) return timeStr + " " + calcDayFromJD(julianday); return timeStr; } //***********************************************************************/ //* Name: calcSun */ //* Type: Main Function called by form controls */ //* Purpose: calculate time of sunrise and sunset for the entered date */ //* and location. In the special cases near earth's poles, */ //* the date of nearest sunrise and set are reported. */ //* Arguments: */ //* riseSetForm : for displaying results */ //* latLongForm : for reading latitude and longitude data */ //* index : daylight saving yes/no select */ //* index2 : city select index */ //* Return value: */ //* none */ //* (fills riseSetForm text fields with results of calculations) */ //***********************************************************************/ function calcSun(riseSetForm, latLongForm, index, index2) { if(index2 != 0) { setLatLong(latLongForm, index2); } var latitude = getLatitude(latLongForm); var longitude = getLongitude(latLongForm); var indexRS = riseSetForm.mos.selectedIndex if (isValidInput(riseSetForm, indexRS, latLongForm)) { if((latitude >= -90) && (latitude < -89)) { alert("All latitudes between 89 and 90 S\n will be set to -89"); latLongForm["latDeg"].value = -89; latitude = -89; } if ((latitude <= 90) && (latitude > 89)) { alert("All latitudes between 89 and 90 N\n will be set to 89"); latLongForm["latDeg"].value = 89; latitude = 89; } //***** Calculate the time of sunrise //*********************************************************************/ //**************** NEW STUFF ****** January, 2001 **************** //*********************************************************************/ var JD = calcJD(parseFloat(riseSetForm["year"].value), indexRS + 1, parseFloat(riseSetForm["day"].value)); var dow = calcDayOfWeek(JD); var doy = calcDayOfYear(indexRS + 1, parseFloat(riseSetForm["day"].value), isLeapYear(riseSetForm["year"].value)); var T = calcTimeJulianCent(JD); var alpha = calcSunRtAscension(T); var theta = calcSunDeclination(T); var Etime = calcEquationOfTime(T); //riseSetForm["dbug"].value = doy; //*********************************************************************/ var eqTime = Etime; var solarDec = theta; // Calculate sunrise for this date // if no sunrise is found, set flag nosunrise var nosunrise = false; var riseTimeGMT = calcSunriseUTC(JD, latitude, longitude); if (!isNumber(riseTimeGMT)) { nosunrise = true; } // Calculate sunset for this date // if no sunset is found, set flag nosunset var nosunset = false; var setTimeGMT = calcSunsetUTC(JD, latitude, longitude); if (!isNumber(setTimeGMT)) { nosunset = true; } var daySavings = YesNo[index].value; // = 0 (no) or 60 (yes) var zone = latLongForm["hrsToGMT"].value; if(zone > 12 || zone < -12.5) { alert("The offset must be between -12.5 and 12. \n Setting \"Off-Set\"=0"); zone = "0"; latLongForm["hrsToGMT"].value = zone; } if (!nosunrise) // Sunrise was found { var riseTimeLST = riseTimeGMT - (60 * zone) + daySavings; // in minutes var riseStr = timeStringShortAMPM(riseTimeLST, JD); var utcRiseStr = timeStringDate(riseTimeGMT, JD); riseSetForm["sunrise"].value = riseStr; riseSetForm["utcsunrise"].value = utcRiseStr; } if (!nosunset) // Sunset was found { var setTimeLST = setTimeGMT - (60 * zone) + daySavings; var setStr = timeStringShortAMPM(setTimeLST, JD); var utcSetStr = timeStringDate(setTimeGMT, JD); riseSetForm["sunset"].value = setStr; riseSetForm["utcsunset"].value = utcSetStr; } // Calculate solar noon for this date var solNoonGMT = calcSolNoonUTC(T, longitude); var solNoonLST = solNoonGMT - (60 * zone) + daySavings; var solnStr = timeString(solNoonLST); var utcSolnStr = timeString(solNoonGMT); riseSetForm["solnoon"].value = solnStr; riseSetForm["utcsolnoon"].value = utcSolnStr; var tsnoon = calcTimeJulianCent(calcJDFromJulianCent(T) -0.5 + solNoonGMT/1440.0); eqTime = calcEquationOfTime(tsnoon); solarDec = calcSunDeclination(tsnoon); riseSetForm["eqTime"].value = (Math.floor(100*eqTime))/100; riseSetForm["solarDec"].value = (Math.floor(100*(solarDec)))/100; //***********Convert lat and long to standard format convLatLong(latLongForm); // report special cases of no sunrise if(nosunrise) { riseSetForm["utcsunrise"].value = ""; // if Northern hemisphere and spring or summer, OR // if Southern hemisphere and fall or winter, use // previous sunrise and next sunset if ( ((latitude > 66.4) && (doy > 79) && (doy < 267)) || ((latitude < -66.4) && ((doy < 83) || (doy > 263))) ) { newjd = findRecentSunrise(JD, latitude, longitude); newtime = calcSunriseUTC(newjd, latitude, longitude) - (60 * zone) + daySavings; if (newtime > 1440) { newtime -= 1440; newjd += 1.0; } if (newtime < 0) { newtime += 1440; newjd -= 1.0; } riseSetForm["sunrise"].value = timeStringAMPMDate(newtime, newjd); riseSetForm["utcsunrise"].value = "prior sunrise"; } // if Northern hemisphere and fall or winter, OR // if Southern hemisphere and spring or summer, use // next sunrise and previous sunset else if ( ((latitude > 66.4) && ((doy < 83) || (doy > 263))) || ((latitude < -66.4) && (doy > 79) && (doy < 267)) ) { newjd = findNextSunrise(JD, latitude, longitude); newtime = calcSunriseUTC(newjd, latitude, longitude) - (60 * zone) + daySavings; if (newtime > 1440) { newtime -= 1440; newjd += 1.0; } if (newtime < 0) { newtime += 1440; newjd -= 1.0; } riseSetForm["sunrise"].value = timeStringAMPMDate(newtime, newjd); // riseSetForm["sunrise"].value = calcDayFromJD(newjd) // + " " + timeStringDate(newtime, newjd); riseSetForm["utcsunrise"].value = "next sunrise"; } else { alert("Cannot Find Sunrise!"); } // alert("Last Sunrise was on day " + findRecentSunrise(JD, latitude, longitude)); // alert("Next Sunrise will be on day " + findNextSunrise(JD, latitude, longitude)); } if(nosunset) { riseSetForm["utcsunset"].value = ""; // if Northern hemisphere and spring or summer, OR // if Southern hemisphere and fall or winter, use // previous sunrise and next sunset if ( ((latitude > 66.4) && (doy > 79) && (doy < 267)) || ((latitude < -66.4) && ((doy < 83) || (doy > 263))) ) { newjd = findNextSunset(JD, latitude, longitude); newtime = calcSunsetUTC(newjd, latitude, longitude) - (60 * zone) + daySavings; if (newtime > 1440) { newtime -= 1440; newjd += 1.0; } if (newtime < 0) { newtime += 1440; newjd -= 1.0; } riseSetForm["sunset"].value = timeStringAMPMDate(newtime, newjd); riseSetForm["utcsunset"].value = "next sunset"; riseSetForm["utcsolnoon"].value = ""; } // if Northern hemisphere and fall or winter, OR // if Southern hemisphere and spring or summer, use // next sunrise and last sunset else if ( ((latitude > 66.4) && ((doy < 83) || (doy > 263))) || ((latitude < -66.4) && (doy > 79) && (doy < 267)) ) { newjd = findRecentSunset(JD, latitude, longitude); newtime = calcSunsetUTC(newjd, latitude, longitude) - (60 * zone) + daySavings; if (newtime > 1440) { newtime -= 1440; newjd += 1.0; } if (newtime < 0) { newtime += 1440; newjd -= 1.0; } riseSetForm["sunset"].value = timeStringAMPMDate(newtime, newjd); riseSetForm["utcsunset"].value = "prior sunset"; riseSetForm["solnoon"].value = "N/A"; riseSetForm["utcsolnoon"].value = ""; } else { alert ("Cannot Find Sunset!"); } } } } //*********************************************************************/ </SCRIPT> <FORM NAME="cityLatLong"> <CENTER><TABLE BORDER> <TR> <TD ALIGN="CENTER"><H5>City:</TD> <TD></TD> <TD ALIGN="CENTER"><H5>Deg:</TD> <TD ALIGN="CENTER"><H5>Min:</TD> <TD ALIGN="CENTER"><H5>Sec:</TD> <TD ALIGN="CENTER" COLSPAN="2"><H5><a href="./timezone.html">Time Zone</TD> </TR> <TR> <TD ALIGN="TOP"> <CENTER> <SELECT NAME="cities" onChange="calcSun(riseSetCalc, cityLatLong, cityLatLong.dayAns.selectedIndex, cityLatLong.cities.selectedIndex);"> <SCRIPT LANGUAGE="JavaScript"> for (i = 0; i < City.length; i++) { if(City[i].name == "Boulder, CO") { document.writeln("<OPTION SELECTED>" + City[i].name); } else document.writeln("<OPTION>" + City[i].name); } </SCRIPT> </SELECT> </CENTER> </TD> <TD ALIGN="CENTER"><H5><a href="./glossary.html#latitude">Lat</a>:<BR>North=+<BR>South=<FONT SIZE = 4>-</FONT></TD> <TD><INPUT TYPE="text" NAME="latDeg" VALUE="40" SIZE="4"></TD> <TD><INPUT TYPE="text" NAME="latMin" VALUE="7" SIZE="4"></TD> <TD><INPUT TYPE="text" NAME="latSec" VALUE="30" SIZE="4"></TD> <TD ROWSPAN=2 ALIGN="CENTER"><H5>Offset<BR>to <a href="./glossary.html#UTC">UTC</a><BR>(MST=+7):<BR></H5> <INPUT TYPE="text" NAME="hrsToGMT" VALUE="7" SIZE="5"></TD> <TD ROWSPAN=2 ALIGN = "CENTER"><H5><a href="./glossary.html#daylightsavingtime">Daylight<BR>Saving<BR>Time</a>:<BR></H5> <SELECT NAME="dayAns" onChange="calcSun(riseSetCalc, cityLatLong, cityLatLong.dayAns.selectedIndex, cityLatLong.cities.selectedIndex);"> <SCRIPT LANGUAGE="JavaScript"> for(i=0; i < YesNo.length; i++) { document.writeln("<OPTION>" + YesNo[i].daySave); } </SCRIPT> </SELECT> </TD> </TR> <TR> <TD ALIGN="CENTER"><H5><a href="./sollinks.html#latlong">Click here for help finding<br> your lat/long coordinates</a> </TD> <TD ALIGN="CENTER"><H5><a href="./glossary.html#longitude">Long</a>:<BR>West=+<BR>East=<FONT SIZE = 4>-</FONT></TD> <TD><INPUT TYPE="text" NAME="lonDeg" VALUE="105" SIZE="4"></TD> <TD><INPUT TYPE="text" NAME="lonMin" VALUE="14" SIZE="4"></TD> <TD><INPUT TYPE="text" NAME="lonSec" VALUE="13" SIZE="4"></TD> </TR> <TR> <TD COLSPAN=7> <b>Note:</b> To manually enter latitude/longitude, select <b>Enter Lat/Long -></b> from the<br>City pulldown menu, and enter the values in the text boxes to the right. </TD></TR> </TABLE> </CENTER> </FORM> <FORM NAME="riseSetCalc"> <CENTER><TABLE BORDER> <TR> <TD ALIGN="CENTER"><H5>Month:</TD> <TD ALIGN="CENTER"><H5>Day:</TD> <TD ALIGN="CENTER"><H5>Year (e.g. 2000):</TD> </TR> <TR> <TD> <SELECT NAME="mos" onChange="calcSun(riseSetCalc, cityLatLong, cityLatLong.dayAns.selectedIndex, cityLatLong.cities.selectedIndex);"> <SCRIPT LANGUAGE="JavaScript"> dateObj1 = new Date(); thismonth = dateObj1.getMonth(); today = dateObj1.getDate(); for (i = 0; i < monthList.length; i++) { if (i == thismonth) { document.writeln("<OPTION SELECTED>" + monthList[i].name); } else { document.writeln("<OPTION>" + monthList[i].name); } } </SCRIPT> </SELECT> </TD> <SCRIPT LANGUAGE="JavaScript"> dateObj2 = new Date(); thisday = dateObj2.getDate(); document.writeln("<TD><CENTER><INPUT TYPE=\"text\" NAME=\"day\" SIZE=\"2\" VALUE=\"" + thisday + "\"></TD>"); dateObj3 = new Date(); thisYear = dateObj3.getYear(); if(thisYear <=199) { thisYear=(thisYear*1)+1900; } document.writeln("<TD><CENTER><INPUT TYPE=\"text\" NAME=\"year\" SIZE=\"4\"VALUE=\"" + thisYear*1 + "\"></TD>"); </SCRIPT> </TR> </TABLE> <br> <INPUT TYPE="button" NAME="RiseSet" VALUE=" Calculate Sunrise/Sunset " onClick="calcSun(riseSetCalc, cityLatLong, cityLatLong.dayAns.selectedIndex, cityLatLong.cities.selectedIndex);"> <br> <BR> <TABLE BORDER> <TR> <TD ALIGN="CENTER"><H5><a href="./glossary.html#equationoftime">Equation <BR>of Time</a><BR>(minutes):</TD> <TD ALIGN="CENTER"><H5><a href="./glossary.html#solardeclination">Solar<BR>Declination</a><BR> (degrees):</TD> <TD ALIGN="CENTER"><H5><a href="./glossary.html#apparentsunrise">Apparent<br>Sunrise</a>:</TD> <TD ALIGN="CENTER"><H5><a href="./glossary.html#solarnoon">Solar Noon</a>:</TD> <TD ALIGN="CENTER"><H5><a href="./glossary.html#apparentsunrise">Apparent<br>Sunset</a>:</TD> <TD ALIGN="CENTER"><H5>Time<br>Zone</TD> </TR> <TR> <TD><CENTER><INPUT TYPE="text" NAME="eqTime" SIZE = "8"></TD> <TD><CENTER><INPUT TYPE="text" NAME="solarDec" SIZE = "8"></TD> <TD><CENTER><INPUT TYPE="text" NAME="sunrise" SIZE="13"></TD> <TD><CENTER><INPUT TYPE="text" NAME="solnoon" SIZE="8"></TD> <TD><CENTER><INPUT TYPE="text" NAME="sunset" SIZE="13"></TD> <TD ALIGN="LEFT"><H5>Local</TD> </TR> <TR> <TD ALIGN="CENTER" COLSPAN="2">  </TD> <TD><CENTER><INPUT TYPE="text" NAME="utcsunrise" SIZE="13"></TD> <TD><CENTER><INPUT TYPE="text" NAME="utcsolnoon" SIZE="8"></TD> <TD><CENTER><INPUT TYPE="text" NAME="utcsunset" SIZE="13"></TD> <TD ALIGN="CENTER"><H5>UTC</TD> </CENTER></TR> </TABLE> </CENTER> </FORM></FONT> <HR> <CENTER><P> <B><H3>Directions:</b><BR><FONT SIZE=2> </CENTER> <OL> <LI> Select a location from the City pulldown menu, <U>OR</U> select <b>"Enter Lat/Long ->"</b> from the pulldown menu, and manually enter the latitude, longitude and time zone information in the appropriate text boxes. The following sign conventions are used: </P></FONT> <CENTER><TABLE BORDER> <TR> <TD ALIGN="CENTER"><B><FONT SIZE =2>Longitude:</B></TD> <TD ALIGN="CENTER"><B><FONT SIZE =2>Latitude:</B></TD> </TR> <TR> <TD ALIGN="CENTER"><FONT SIZE =2>Positive in Western Hemisphere</TD> <TD ALIGN="CENTER"><FONT SIZE =2>Positive in Northern Hemisphere</TD> </TR> <TR> <TD ALIGN="CENTER"><FONT SIZE =2>Negative in Eastern Hemisphere</TD> <TD ALIGN="CENTER"><FONT SIZE =2>Negative in Southern Hemisphere</TD> </TR> </TABLE> <P> </CENTER><FONT SIZE=2> Latitude and Longitude can be in deg/min/sec, or decimal degrees entered in the "Deg:" field. If you select a city from the pulldown menu, the latitude, longitude and time zone fields will be filled in automatically. If you want to input latitude, longitude or time zone manually, <u>be sure to select "Enter Lat/Long -->" from the City pulldown box, or your numbers will be overwritten</u> by the selected city's location. </P> </LI> <LI> <P> You can enter a different time zone for a location by selecting "Enter Lat/Long -->" in the City pulldown box. Otherwise, the time zone associated with the selected city's Local Standard Time will be automatically entered. Selecting "Yes" in the Daylight Saving field will cause the resulting sunrise, sunset and solar noon times to be adjusted forward one hour. If you are uncertain of the time zone for a location, refer to our <a href="./timezone.html">Time Zone Table</a>. </P> </LI> <LI> <P> The program retrieves the current date from your computer, and fills the month, day and year fields. To perform calculations for a different date, simply select a month in the pull down menu, and enter the day and four digit year in the appropriate input boxes. When entering a day or year, you will need to click the "Calculate Sunrise/Sunset" button to update the results for this date. </P> </LI> <LI> <P> Once the calculation results are displayed, you may use your web browser's "Print" function to obtain a hardcopy of the results. </P> </LI> <LI> <P> For locations above the Arctic Circle and below the Antarctic Circle, when a sunrise or sunset does not occur on the given day the program locates the local time and date of the most recent sunrise or sunset, and the next sunset or sunrise. When this occurs, the UTC fields will display "prior" or "next" information instead of the UTC times. </P> </LI> <LI> <P> NOTE: For latitudes greater than 72 degrees N and S, calculations are accurate to within 10 minutes. For latitudes less than +/- 72° accuracy is approximately one minute. See <a href="./calcdetails.html">Solar Calculation Details</a> for further explanation. </P> </LI> </OL> </FONT> <BR> <HR> <h4> <table border=0 width="100%"> <tr> <td align="left"> <a href="./azel.html">Solar Position Calculator</a><br> <a href="./calcdetails.html">Calculation Details</a><br> <a href="./sollinks.html">Solar Calculator Links</a><br> </td> <td align="center"> <a href="http://www.noaa.gov/"><img src="./noaaemblemt.gif" border="0" alt="NOAA Emblem"></a> </td> <td align="right"> <a href="./timezone.html">Time Zone Table</a><br> <a href="./glossary.html">Solar Calculator Glossary</a><br> <a href="/index.html">Back to SRRB Homepage</a><br> </td> </tr> </table> </h4> <center>by <a href="mailto:webmaster.gml@noaa.gov">Chris Cornwall</a>, Aaron Horiuchi and Chris Lehman<br> <SCRIPT> document.write("Last Updated on " + document.lastModified + "."); </SCRIPT> </center> </BODY> </HTML>

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NOAA Improved Sunrise/Sunset Calculation