/* * * * * * * * * * SUNRISET SCRIPT * * * * * * * * * *\
* *
* Computes Sun rise/set times, start/end of twilight. *
* *
* Originally written as DAYLEN.C, 1989-08-16 *
* Modified to SUNRISET.C, 1992-12-01 *
* (c) Paul Schlyter, 1989, 1992 *
* *
* Released to the public domain by Paul Schlyter, Dec. 1992 *
* *
* -- Modified by Bo Johansson 1995-05-12 , 1995-10-14 -- *
* -- Ported to JavaScript by Bo Johansson 1998-05-22 -- *
* -- Very minor revision by Bo Johansson 1999-10-25 -- *
* -- Very minor Y2K fix by Bo Johansson 2000-01-03 -- *
* -- Minor Opera 4 bug fix by Bo Johansson 2000-10-14 -- *
* *
* -- http://w1.545.telia.com/%7Eu54504162/index_e.htm -- *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
// Global variables:
var twAngle = -6.0; // For civil twilight, set to -12.0 for
// nautical, and -18.0 for astr. twilight
var srAngle = -35.0/60.0; // For sunrise/sunset
var sRiseT; // For sunrise/sunset times
var sSetT;
var srStatus;
var twStartT; // For twilight times
var twEndT;
var twStatus;
var sDIST; // Solar distance, astronomical units
var sRA; // Sun's Right Ascension
var sDEC; // Sun's declination
var sLON; // True solar longitude
//-------------------------------------------------------------
// A function to compute the number of days elapsed since
// 2000 Jan 0.0 (which is equal to 1999 Dec 31, 0h UT)
//-------------------------------------------------------------
function dayDiff2000(y, m, d)
{
return (367.0 * y -((7 *(y +((m + 9) / 12))) / 4) +
((275 * m)/9) + d - 730530.0);
}
//-------------------------------------------------------------
// Some conversion factors between radians and degrees
var RADEG = 180.0 / Math.PI;
var DEGRAD = Math.PI / 180.0;
//-------------------------------------------------------------
// The trigonometric functions in degrees
function sind(x) { return Math.sin(x * DEGRAD); }
function cosd(x) { return Math.cos(x * DEGRAD); }
function tand(x) { return Math.tan(x * DEGRAD); }
function atand(x) { return (RADEG * Math.atan(x)); }
function asind(x) { return (RADEG * Math.asin(x)); }
function acosd(x) { return (RADEG * Math.acos(x)); }
//function atan2d(y,x) { return (RADEG*Math.atan2(y,x)); }
function atan2d(y,x) //### Hack to work in MSIE3 ###
{
var at2 = (RADEG * Math.atan(y/x));
if( x < 0 && y < 0)
at2 -= 180;
else if( x < 0 && y > 0)
at2 += 180;
return at2;
}
function sunRiseSet(year, month, day, lat, lon)
{
return (sunTimes(year, month, day, lat, lon, srAngle, 1));
}
function civTwilight(year, month, day, lat, lon)
{
return (sunTimes( year, month, day, lat, lon, twAngle, 0));
}
function sunTimes(year, month, day, lat, lon, altit, sUppLimb)
{
var dayDiff; // Days since 2000 Jan 0.0 (negative before)
var sRadius; // Sun's apparent radius
var diuArc; // Diurnal arc
var sSouthT; // Time when Sun is at south
var locSidT; // Local sidereal time
var stCode = 0; // Status code from function - usually 0
/* Compute dayDiff of 12h local mean solar time */
dayDiff = dayDiff2000(year, month, day) + 0.5 - lon/360.0;
/* Compute local sideral time of this moment */
locSidT = revolution( GMST0(dayDiff) + 180.0 + lon );
/* Compute Sun's RA + Decl at this moment */
sunRaDec( dayDiff );
/* Compute time when Sun is at south - in hours UT */
sSouthT = 12.0 - rev180(locSidT - sRA)/15.0;
/* Compute the Sun's apparent radius, degrees */
sRadius = 0.2666 / sDIST;
/* Do correction to upper limb, if necessary */
if ( sUppLimb != 0) // For surise/sunset
altit -= sRadius;
/* Compute the diurnal arc that the Sun traverses */
/* to reach the specified altitude altit: */
var cost = ( sind(altit) - sind(lat) * sind(sDEC) ) /
( cosd(lat) * cosd(sDEC) );
if ( cost >= 1.0 )
{
stCode = -1;
diuArc = 0.0; // Sun always below altit
}
else if ( cost <= -1.0 )
{
stCode = 1;
diuArc = 12.0; // Sun always above altit
}
else
{ // *** Opera bug fix 2000-10-14
// The diurnal arc, hours
diuArc = acosd(cost)/15.0;
}
/* Compute rise and set times - in hours UT */
if ( sUppLimb != 0) // For sunrise/sunset
{
sRiseT = sSouthT - diuArc;
if(sRiseT < 0) // Sunrise day before
sRiseT += 24;
sSetT = sSouthT + diuArc;
if(sSetT > 24) // Sunset next day
sSetT -= 24;
srStatus = stCode;
}
else // For twilight times
{
twStartT = sSouthT - diuArc;
if(twStartT < 0)
twStartT += 24;
twEndT = sSouthT + diuArc;
if(twEndT > 24)
twEndT -= 24;
twStatus = stCode;
}
} //================== sunTimes() =====================
function sunRaDec(dayDiff)
{
var eclObl; // Obliquity of ecliptic
// (inclination of Earth's axis)
var x;
var y;
var z;
/* Compute Sun's ecliptical coordinates */
sunPos( dayDiff );
/* Compute ecliptic rectangular coordinates (z=0) */
x = sDIST * cosd(sLON);
y = sDIST * sind(sLON);
/* Compute obliquity of ecliptic */
/* (inclination of Earth's axis) */
// eclObl = 23.4393 - 3.563E-7 * dayDiff;
eclObl = 23.4393 - 3.563/10000000 * dayDiff; // for Opera
/* Convert to equatorial rectangular coordinates */
/* - x is uchanged */
z = y * sind(eclObl);
y = y * cosd(eclObl);
/* Convert to spherical coordinates */
sRA = atan2d( y, x );
sDEC = atan2d( z, Math.sqrt(x*x + y*y) );
} //================= sunRaDec() =======================
function sunPos(dayDiff)
{
var M; // Mean anomaly of the Sun
var w; // Mean longitude of perihelion
// Note: Sun's mean longitude = M + w
var e; // Eccentricity of Earth's orbit
var eAN; // Eccentric anomaly
var x; // x, y coordinates in orbit
var y;
var v; // True anomaly
/* Compute mean elements */
M = revolution( 356.0470 + 0.9856002585 * dayDiff );
// w = 282.9404 + 4.70935E-5 * dayDiff;
// e = 0.016709 - 1.151E-9 * dayDiff;
w = 282.9404 + 4.70935/100000 * dayDiff; // for Opera
e = 0.016709 - 1.151/1000000000 * dayDiff; // for Opera
/* Compute true longitude and radius vector */
eAN = M + e * RADEG * sind(M) * ( 1.0 + e * cosd(M) );
x = cosd(eAN) - e;
y = Math.sqrt( 1.0 - e*e ) * sind(eAN);
sDIST = Math.sqrt( x*x + y*y ); // Solar distance
v = atan2d( y, x ); // True anomaly
sLON = v + w; // True solar longitude
if ( sLON >= 360.0 )
sLON -= 360.0; // Make it 0..360 degrees
} //=================== sunPos() =============================
var INV360 = 1.0 / 360.0;
function revolution( x )
{
return (x - 360.0 * Math.floor( x * INV360 ));
}
function rev180( x )
{
return ( x - 360.0 * Math.floor( x * INV360 + 0.5 ) );
}
function GMST0( dayDiff )
{
var const1 = 180.0 + 356.0470 + 282.9404;
// var const2 = 0.9856002585 + 4.70935E-5;
var const2 = 0.9856002585 + 4.70935/100000; // for Opera
return ( revolution( const1 + const2 * dayDiff ) );
} //=================== GMST0() =========================
function toDayValues(name, lat, lon)
{
toDay = new Date();
var year = toDay.getYear();
if (year < 1900) // **** fixed 2000-01-03
year += 1900;
var month = (toDay.getMonth() + 1);
var day = toDay.getDate();
sunRiseSet(year,month,day,lat,lon);
civTwilight(year,month,day,lat,lon);
showTable(name, lat, lon, year, month, day);
}
function showTable(name, lat, lon, year, month, day)
{
var absLat = Math.abs(lat)
var absLon = Math.abs(lon)
var twsText = "Świt: "
var tweText = "Zmierzch: "
var srText = "Wschód: "
var ssText = "Zachód: "
var twst_h = Math.floor(twStartT)
var twst_m = Math.floor((twStartT - twst_h)*60)
var sris_h = Math.floor(sRiseT)
var sris_m = Math.floor((sRiseT - sris_h)*60)
var sset_h = Math.floor(sSetT)
var sset_m = Math.floor((sSetT - sset_h)*60)
var twen_h = Math.floor(twEndT)
var twen_m = Math.floor((twEndT - twen_h)*60)
if(twStatus == 0)
{
document.write(" " + twsText)
document.write(twst_h + 2 + ".")
if(twst_m < 10)
document.write("0")
document.write(twst_m + "
")
}
if(srStatus == 0)
{
document.write(" " + srText)
document.write(sris_h + 2 + ".")
if(sris_m < 10)
document.write("0")
document.write(sris_m + "
")
document.write(" " + ssText)
document.write(sset_h + 2 + ".")
if(sset_m < 10)
document.write("0")
document.write(sset_m + "
")
}
if(twStatus == 0)
{
document.write(" " + tweText)
document.write(twen_h + 2 + ".")
if(twen_m < 10)
document.write("0")
document.write(twen_m + "
")
}
}
//* * * * * * * * SUNRISET SCRIPT - END - * * * * * * * * *