/* JavaScript functions for positional astronomy by John Walker -- September, MIM http://www.fourmilab.ch/ This program is in the public domain. */ // Frequently-used constants var J2000 = 2451545.0, // Julian day of J2000 epoch JulianCentury = 36525.0, // Days in Julian century JulianMillennium = (JulianCentury * 10), // Days in Julian millennium AstronomicalUnit = 149597870.0, // Astronomical unit in kilometres TropicalYear = 365.24219878; // Mean solar tropical year /* ASTOR -- Arc-seconds to radians. */ function astor(a) { return a * (Math.PI / (180.0 * 3600.0)); } /* DTR -- Degrees to radians. */ function dtr(d) { return (d * Math.PI) / 180.0; } /* RTD -- Radians to degrees. */ function rtd(r) { return (r * 180.0) / Math.PI; } /* FIXANGLE -- Range reduce angle in degrees. */ function fixangle(a) { return a - 360.0 * (Math.floor(a / 360.0)); } /* FIXANGR -- Range reduce angle in radians. */ function fixangr(a) { return a - (2 * Math.PI) * (Math.floor(a / (2 * Math.PI))); } // DSIN -- Sine of an angle in degrees function dsin(d) { return Math.sin(dtr(d)); } // DCOS -- Cosine of an angle in degrees function dcos(d) { return Math.cos(dtr(d)); } /* MOD -- Modulus function which works for non-integers. */ function mod(a, b) { return a - (b * Math.floor(a / b)); } // AMOD -- Modulus function which returns numerator if modulus is zero function amod(a, b) { return mod(a - 1, b) + 1; } /* JHMS -- Convert Julian time to hour, minutes, and seconds, returned as a three-element array. */ function jhms(j) { var ij; j += 0.5; /* Astronomical to civil */ ij = ((j - Math.floor(j)) * 86400.0) + 0.5; return new Array( Math.floor(ij / 3600), Math.floor((ij / 60) % 60), Math.floor(ij % 60)); } // JWDAY -- Calculate day of week from Julian day var Weekdays = new Array( "Sonntag", "Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag" ); function jwday(j) { return mod(Math.floor((j + 1.5)), 7); } /* OBLIQEQ -- Calculate the obliquity of the ecliptic for a given Julian date. This uses Laskar's tenth-degree polynomial fit (J. Laskar, Astronomy and Astrophysics, Vol. 157, page 68 [1986]) which is accurate to within 0.01 arc second between AD 1000 and AD 3000, and within a few seconds of arc for +/-10000 years around AD 2000. If we're outside the range in which this fit is valid (deep time) we simply return the J2000 value of the obliquity, which happens to be almost precisely the mean. */ var oterms = new Array ( -4680.93, -1.55, 1999.25, -51.38, -249.67, -39.05, 7.12, 27.87, 5.79, 2.45 ); function obliqeq(jd) { var eps, u, v, i; v = u = (jd - J2000) / (JulianCentury * 100); eps = 23 + (26 / 60.0) + (21.448 / 3600.0); if (Math.abs(u) < 1.0) { for (i = 0; i < 10; i++) { eps += (oterms[i] / 3600.0) * v; v *= u; } } return eps; } /* Periodic terms for nutation in longiude (delta \Psi) and obliquity (delta \Epsilon) as given in table 21.A of Meeus, "Astronomical Algorithms", first edition. */ var nutArgMult = new Array( 0, 0, 0, 0, 1, -2, 0, 0, 2, 2, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, -2, 1, 0, 2, 2, 0, 0, 0, 2, 1, 0, 0, 1, 2, 2, -2, -1, 0, 2, 2, -2, 0, 1, 0, 0, -2, 0, 0, 2, 1, 0, 0, -1, 2, 2, 2, 0, 0, 0, 0, 0, 0, 1, 0, 1, 2, 0, -1, 2, 2, 0, 0, -1, 0, 1, 0, 0, 1, 2, 1, -2, 0, 2, 0, 0, 0, 0, -2, 2, 1, 2, 0, 0, 2, 2, 0, 0, 2, 2, 2, 0, 0, 2, 0, 0, -2, 0, 1, 2, 2, 0, 0, 0, 2, 0, -2, 0, 0, 2, 0, 0, 0, -1, 2, 1, 0, 2, 0, 0, 0, 2, 0, -1, 0, 1, -2, 2, 0, 2, 2, 0, 1, 0, 0, 1, -2, 0, 1, 0, 1, 0, -1, 0, 0, 1, 0, 0, 2, -2, 0, 2, 0, -1, 2, 1, 2, 0, 1, 2, 2, 0, 1, 0, 2, 2, -2, 1, 1, 0, 0, 0, -1, 0, 2, 2, 2, 0, 0, 2, 1, 2, 0, 1, 0, 0, -2, 0, 2, 2, 2, -2, 0, 1, 2, 1, 2, 0, -2, 0, 1, 2, 0, 0, 0, 1, 0, -1, 1, 0, 0, -2, -1, 0, 2, 1, -2, 0, 0, 0, 1, 0, 0, 2, 2, 1, -2, 0, 2, 0, 1, -2, 1, 0, 2, 1, 0, 0, 1, -2, 0, -1, 0, 1, 0, 0, -2, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 2, 0, -1, -1, 1, 0, 0, 0, 1, 1, 0, 0, 0, -1, 1, 2, 2, 2, -1, -1, 2, 2, 0, 0, -2, 2, 2, 0, 0, 3, 2, 2, 2, -1, 0, 2, 2 ); var nutArgCoeff = new Array( -171996, -1742, 92095, 89, /* 0, 0, 0, 0, 1 */ -13187, -16, 5736, -31, /* -2, 0, 0, 2, 2 */ -2274, -2, 977, -5, /* 0, 0, 0, 2, 2 */ 2062, 2, -895, 5, /* 0, 0, 0, 0, 2 */ 1426, -34, 54, -1, /* 0, 1, 0, 0, 0 */ 712, 1, -7, 0, /* 0, 0, 1, 0, 0 */ -517, 12, 224, -6, /* -2, 1, 0, 2, 2 */ -386, -4, 200, 0, /* 0, 0, 0, 2, 1 */ -301, 0, 129, -1, /* 0, 0, 1, 2, 2 */ 217, -5, -95, 3, /* -2, -1, 0, 2, 2 */ -158, 0, 0, 0, /* -2, 0, 1, 0, 0 */ 129, 1, -70, 0, /* -2, 0, 0, 2, 1 */ 123, 0, -53, 0, /* 0, 0, -1, 2, 2 */ 63, 0, 0, 0, /* 2, 0, 0, 0, 0 */ 63, 1, -33, 0, /* 0, 0, 1, 0, 1 */ -59, 0, 26, 0, /* 2, 0, -1, 2, 2 */ -58, -1, 32, 0, /* 0, 0, -1, 0, 1 */ -51, 0, 27, 0, /* 0, 0, 1, 2, 1 */ 48, 0, 0, 0, /* -2, 0, 2, 0, 0 */ 46, 0, -24, 0, /* 0, 0, -2, 2, 1 */ -38, 0, 16, 0, /* 2, 0, 0, 2, 2 */ -31, 0, 13, 0, /* 0, 0, 2, 2, 2 */ 29, 0, 0, 0, /* 0, 0, 2, 0, 0 */ 29, 0, -12, 0, /* -2, 0, 1, 2, 2 */ 26, 0, 0, 0, /* 0, 0, 0, 2, 0 */ -22, 0, 0, 0, /* -2, 0, 0, 2, 0 */ 21, 0, -10, 0, /* 0, 0, -1, 2, 1 */ 17, -1, 0, 0, /* 0, 2, 0, 0, 0 */ 16, 0, -8, 0, /* 2, 0, -1, 0, 1 */ -16, 1, 7, 0, /* -2, 2, 0, 2, 2 */ -15, 0, 9, 0, /* 0, 1, 0, 0, 1 */ -13, 0, 7, 0, /* -2, 0, 1, 0, 1 */ -12, 0, 6, 0, /* 0, -1, 0, 0, 1 */ 11, 0, 0, 0, /* 0, 0, 2, -2, 0 */ -10, 0, 5, 0, /* 2, 0, -1, 2, 1 */ -8, 0, 3, 0, /* 2, 0, 1, 2, 2 */ 7, 0, -3, 0, /* 0, 1, 0, 2, 2 */ -7, 0, 0, 0, /* -2, 1, 1, 0, 0 */ -7, 0, 3, 0, /* 0, -1, 0, 2, 2 */ -7, 0, 3, 0, /* 2, 0, 0, 2, 1 */ 6, 0, 0, 0, /* 2, 0, 1, 0, 0 */ 6, 0, -3, 0, /* -2, 0, 2, 2, 2 */ 6, 0, -3, 0, /* -2, 0, 1, 2, 1 */ -6, 0, 3, 0, /* 2, 0, -2, 0, 1 */ -6, 0, 3, 0, /* 2, 0, 0, 0, 1 */ 5, 0, 0, 0, /* 0, -1, 1, 0, 0 */ -5, 0, 3, 0, /* -2, -1, 0, 2, 1 */ -5, 0, 3, 0, /* -2, 0, 0, 0, 1 */ -5, 0, 3, 0, /* 0, 0, 2, 2, 1 */ 4, 0, 0, 0, /* -2, 0, 2, 0, 1 */ 4, 0, 0, 0, /* -2, 1, 0, 2, 1 */ 4, 0, 0, 0, /* 0, 0, 1, -2, 0 */ -4, 0, 0, 0, /* -1, 0, 1, 0, 0 */ -4, 0, 0, 0, /* -2, 1, 0, 0, 0 */ -4, 0, 0, 0, /* 1, 0, 0, 0, 0 */ 3, 0, 0, 0, /* 0, 0, 1, 2, 0 */ -3, 0, 0, 0, /* -1, -1, 1, 0, 0 */ -3, 0, 0, 0, /* 0, 1, 1, 0, 0 */ -3, 0, 0, 0, /* 0, -1, 1, 2, 2 */ -3, 0, 0, 0, /* 2, -1, -1, 2, 2 */ -3, 0, 0, 0, /* 0, 0, -2, 2, 2 */ -3, 0, 0, 0, /* 0, 0, 3, 2, 2 */ -3, 0, 0, 0 /* 2, -1, 0, 2, 2 */ ); /* NUTATION -- Calculate the nutation in longitude, deltaPsi, and obliquity, deltaEpsilon for a given Julian date jd. Results are returned as a two element Array giving (deltaPsi, deltaEpsilon) in degrees. */ function nutation(jd) { var deltaPsi, deltaEpsilon, i, j, t = (jd - 2451545.0) / 36525.0, t2, t3, to10, ta = new Array, dp = 0, de = 0, ang; t3 = t * (t2 = t * t); /* Calculate angles. The correspondence between the elements of our array and the terms cited in Meeus are: ta[0] = D ta[0] = M ta[2] = M' ta[3] = F ta[4] = \Omega */ ta[0] = dtr(297.850363 + 445267.11148 * t - 0.0019142 * t2 + t3 / 189474.0); ta[1] = dtr(357.52772 + 35999.05034 * t - 0.0001603 * t2 - t3 / 300000.0); ta[2] = dtr(134.96298 + 477198.867398 * t + 0.0086972 * t2 + t3 / 56250.0); ta[3] = dtr(93.27191 + 483202.017538 * t - 0.0036825 * t2 + t3 / 327270); ta[4] = dtr(125.04452 - 1934.136261 * t + 0.0020708 * t2 + t3 / 450000.0); /* Range reduce the angles in case the sine and cosine functions don't do it as accurately or quickly. */ for (i = 0; i < 5; i++) { ta[i] = fixangr(ta[i]); } to10 = t / 10.0; for (i = 0; i < 63; i++) { ang = 0; for (j = 0; j < 5; j++) { if (nutArgMult[(i * 5) + j] != 0) { ang += nutArgMult[(i * 5) + j] * ta[j]; } } dp += (nutArgCoeff[(i * 4) + 0] + nutArgCoeff[(i * 4) + 1] * to10) * Math.sin(ang); de += (nutArgCoeff[(i * 4) + 2] + nutArgCoeff[(i * 4) + 3] * to10) * Math.cos(ang); } /* Return the result, converting from ten thousandths of arc seconds to radians in the process. */ deltaPsi = dp / (3600.0 * 10000.0); deltaEpsilon = de / (3600.0 * 10000.0); return new Array(deltaPsi, deltaEpsilon); } /* ECLIPTOEQ -- Convert celestial (ecliptical) longitude and latitude into right ascension (in degrees) and declination. We must supply the time of the conversion in order to compensate correctly for the varying obliquity of the ecliptic over time. The right ascension and declination are returned as a two-element Array in that order. */ function ecliptoeq(jd, Lambda, Beta) { var eps, Ra, Dec; /* Obliquity of the ecliptic. */ eps = dtr(obliqeq(jd)); log += "Obliquity: " + rtd(eps) + "\n"; Ra = rtd(Math.atan2((Math.cos(eps) * Math.sin(dtr(Lambda)) - (Math.tan(dtr(Beta)) * Math.sin(eps))), Math.cos(dtr(Lambda)))); log += "RA = " + Ra + "\n"; Ra = fixangle(rtd(Math.atan2((Math.cos(eps) * Math.sin(dtr(Lambda)) - (Math.tan(dtr(Beta)) * Math.sin(eps))), Math.cos(dtr(Lambda))))); Dec = rtd(Math.asin((Math.sin(eps) * Math.sin(dtr(Lambda)) * Math.cos(dtr(Beta))) + (Math.sin(dtr(Beta)) * Math.cos(eps)))); return new Array(Ra, Dec); } /* DELTAT -- Determine the difference, in seconds, between Dynamical time and Universal time. */ /* Table of observed Delta T values at the beginning of even numbered years from 1620 through 2002. */ var deltaTtab = new Array( 121, 112, 103, 95, 88, 82, 77, 72, 68, 63, 60, 56, 53, 51, 48, 46, 44, 42, 40, 38, 35, 33, 31, 29, 26, 24, 22, 20, 18, 16, 14, 12, 11, 10, 9, 8, 7, 7, 7, 7, 7, 7, 8, 8, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 15, 15, 14, 13, 13.1, 12.5, 12.2, 12, 12, 12, 12, 12, 12, 11.9, 11.6, 11, 10.2, 9.2, 8.2, 7.1, 6.2, 5.6, 5.4, 5.3, 5.4, 5.6, 5.9, 6.2, 6.5, 6.8, 7.1, 7.3, 7.5, 7.6, 7.7, 7.3, 6.2, 5.2, 2.7, 1.4, -1.2, -2.8, -3.8, -4.8, -5.5, -5.3, -5.6, -5.7, -5.9, -6, -6.3, -6.5, -6.2, -4.7, -2.8, -0.1, 2.6, 5.3, 7.7, 10.4, 13.3, 16, 18.2, 20.2, 21.1, 22.4, 23.5, 23.8, 24.3, 24, 23.9, 23.9, 23.7, 24, 24.3, 25.3, 26.2, 27.3, 28.2, 29.1, 30, 30.7, 31.4, 32.2, 33.1, 34, 35, 36.5, 38.3, 40.2, 42.2, 44.5, 46.5, 48.5, 50.5, 52.2, 53.8, 54.9, 55.8, 56.9, 58.3, 60, 61.6, 63, 65, 66.6 ); function deltat(year) { var dt, f, i, t; if ((year >= 1620) && (year <= 2000)) { i = Math.floor((year - 1620) / 2); f = ((year - 1620) / 2) - i; /* Fractional part of year */ dt = deltaTtab[i] + ((deltaTtab[i + 1] - deltaTtab[i]) * f); } else { t = (year - 2000) / 100; if (year < 948) { dt = 2177 + (497 * t) + (44.1 * t * t); } else { dt = 102 + (102 * t) + (25.3 * t * t); if ((year > 2000) && (year < 2100)) { dt += 0.37 * (year - 2100); } } } return dt; } /* EQUINOX -- Determine the Julian Ephemeris Day of an equinox or solstice. The "which" argument selects the item to be computed: 0 March equinox 1 June solstice 2 September equinox 3 December solstice */ // Periodic terms to obtain true time var EquinoxpTerms = new Array( 485, 324.96, 1934.136, 203, 337.23, 32964.467, 199, 342.08, 20.186, 182, 27.85, 445267.112, 156, 73.14, 45036.886, 136, 171.52, 22518.443, 77, 222.54, 65928.934, 74, 296.72, 3034.906, 70, 243.58, 9037.513, 58, 119.81, 33718.147, 52, 297.17, 150.678, 50, 21.02, 2281.226, 45, 247.54, 29929.562, 44, 325.15, 31555.956, 29, 60.93, 4443.417, 18, 155.12, 67555.328, 17, 288.79, 4562.452, 16, 198.04, 62894.029, 14, 199.76, 31436.921, 12, 95.39, 14577.848, 12, 287.11, 31931.756, 12, 320.81, 34777.259, 9, 227.73, 1222.114, 8, 15.45, 16859.074 ); JDE0tab1000 = new Array( new Array(1721139.29189, 365242.13740, 0.06134, 0.00111, -0.00071), new Array(1721233.25401, 365241.72562, -0.05323, 0.00907, 0.00025), new Array(1721325.70455, 365242.49558, -0.11677, -0.00297, 0.00074), new Array(1721414.39987, 365242.88257, -0.00769, -0.00933, -0.00006) ); JDE0tab2000 = new Array( new Array(2451623.80984, 365242.37404, 0.05169, -0.00411, -0.00057), new Array(2451716.56767, 365241.62603, 0.00325, 0.00888, -0.00030), new Array(2451810.21715, 365242.01767, -0.11575, 0.00337, 0.00078), new Array(2451900.05952, 365242.74049, -0.06223, -0.00823, 0.00032) ); function equinox(year, which) { var deltaL, i, j, JDE0, JDE, JDE0tab, S, T, W, Y; /* Initialise terms for mean equinox and solstices. We have two sets: one for years prior to 1000 and a second for subsequent years. */ if (year < 1000) { JDE0tab = JDE0tab1000; Y = year / 1000; } else { JDE0tab = JDE0tab2000; Y = (year - 2000) / 1000; } JDE0 = JDE0tab[which][0] + (JDE0tab[which][1] * Y) + (JDE0tab[which][2] * Y * Y) + (JDE0tab[which][3] * Y * Y * Y) + (JDE0tab[which][4] * Y * Y * Y * Y); //document.debug.log.value += "JDE0 = " + JDE0 + "\n"; T = (JDE0 - 2451545.0) / 36525; //document.debug.log.value += "T = " + T + "\n"; W = (35999.373 * T) - 2.47; //document.debug.log.value += "W = " + W + "\n"; deltaL = 1 + (0.0334 * dcos(W)) + (0.0007 * dcos(2 * W)); //document.debug.log.value += "deltaL = " + deltaL + "\n"; // Sum the periodic terms for time T S = 0; for (i = j = 0; i < 24; i++) { S += EquinoxpTerms[j] * dcos(EquinoxpTerms[j + 1] + (EquinoxpTerms[j + 2] * T)); j += 3; } //document.debug.log.value += "S = " + S + "\n"; //document.debug.log.value += "Corr = " + ((S * 0.00001) / deltaL) + "\n"; JDE = JDE0 + ((S * 0.00001) / deltaL); return JDE; } /* SUNPOS -- Position of the Sun. Please see the comments on the return statement at the end of this function which describe the array it returns. We return intermediate values because they are useful in a variety of other contexts. */ function sunpos(jd) { var T, T2, L0, M, e, C, sunLong, sunAnomaly, sunR, Omega, Lambda, epsilon, epsilon0, Alpha, Delta, AlphaApp, DeltaApp; T = (jd - J2000) / JulianCentury; //document.debug.log.value += "Sunpos. T = " + T + "\n"; T2 = T * T; L0 = 280.46646 + (36000.76983 * T) + (0.0003032 * T2); //document.debug.log.value += "L0 = " + L0 + "\n"; L0 = fixangle(L0); //document.debug.log.value += "L0 = " + L0 + "\n"; M = 357.52911 + (35999.05029 * T) + (-0.0001537 * T2); //document.debug.log.value += "M = " + M + "\n"; M = fixangle(M); //document.debug.log.value += "M = " + M + "\n"; e = 0.016708634 + (-0.000042037 * T) + (-0.0000001267 * T2); //document.debug.log.value += "e = " + e + "\n"; C = ((1.914602 + (-0.004817 * T) + (-0.000014 * T2)) * dsin(M)) + ((0.019993 - (0.000101 * T)) * dsin(2 * M)) + (0.000289 * dsin(3 * M)); //document.debug.log.value += "C = " + C + "\n"; sunLong = L0 + C; //document.debug.log.value += "sunLong = " + sunLong + "\n"; sunAnomaly = M + C; //document.debug.log.value += "sunAnomaly = " + sunAnomaly + "\n"; sunR = (1.000001018 * (1 - (e * e))) / (1 + (e * dcos(sunAnomaly))); //document.debug.log.value += "sunR = " + sunR + "\n"; Omega = 125.04 - (1934.136 * T); //document.debug.log.value += "Omega = " + Omega + "\n"; Lambda = sunLong + (-0.00569) + (-0.00478 * dsin(Omega)); //document.debug.log.value += "Lambda = " + Lambda + "\n"; epsilon0 = obliqeq(jd); //document.debug.log.value += "epsilon0 = " + epsilon0 + "\n"; epsilon = epsilon0 + (0.00256 * dcos(Omega)); //document.debug.log.value += "epsilon = " + epsilon + "\n"; Alpha = rtd(Math.atan2(dcos(epsilon0) * dsin(sunLong), dcos(sunLong))); //document.debug.log.value += "Alpha = " + Alpha + "\n"; Alpha = fixangle(Alpha); ////document.debug.log.value += "Alpha = " + Alpha + "\n"; Delta = rtd(Math.asin(dsin(epsilon0) * dsin(sunLong))); ////document.debug.log.value += "Delta = " + Delta + "\n"; AlphaApp = rtd(Math.atan2(dcos(epsilon) * dsin(Lambda), dcos(Lambda))); //document.debug.log.value += "AlphaApp = " + AlphaApp + "\n"; AlphaApp = fixangle(AlphaApp); //document.debug.log.value += "AlphaApp = " + AlphaApp + "\n"; DeltaApp = rtd(Math.asin(dsin(epsilon) * dsin(Lambda))); //document.debug.log.value += "DeltaApp = " + DeltaApp + "\n"; return new Array( // Angular quantities are expressed in decimal degrees L0, // [0] Geometric mean longitude of the Sun M, // [1] Mean anomaly of the Sun e, // [2] Eccentricity of the Earth's orbit C, // [3] Sun's equation of the Centre sunLong, // [4] Sun's true longitude sunAnomaly, // [5] Sun's true anomaly sunR, // [6] Sun's radius vector in AU Lambda, // [7] Sun's apparent longitude at true equinox of the date Alpha, // [8] Sun's true right ascension Delta, // [9] Sun's true declination AlphaApp, // [10] Sun's apparent right ascension DeltaApp // [11] Sun's apparent declination ); } /* EQUATIONOFTIME -- Compute equation of time for a given moment. Returns the equation of time as a fraction of a day. */ function equationOfTime(jd) { var alpha, deltaPsi, E, epsilon, L0, tau tau = (jd - J2000) / JulianMillennium; //document.debug.log.value += "equationOfTime. tau = " + tau + "\n"; L0 = 280.4664567 + (360007.6982779 * tau) + (0.03032028 * tau * tau) + ((tau * tau * tau) / 49931) + (-((tau * tau * tau * tau) / 15300)) + (-((tau * tau * tau * tau * tau) / 2000000)); //document.debug.log.value += "L0 = " + L0 + "\n"; L0 = fixangle(L0); //document.debug.log.value += "L0 = " + L0 + "\n"; alpha = sunpos(jd)[10]; //document.debug.log.value += "alpha = " + alpha + "\n"; deltaPsi = nutation(jd)[0]; //document.debug.log.value += "deltaPsi = " + deltaPsi + "\n"; epsilon = obliqeq(jd) + nutation(jd)[1]; //document.debug.log.value += "epsilon = " + epsilon + "\n"; E = L0 + (-0.0057183) + (-alpha) + (deltaPsi * dcos(epsilon)); //document.debug.log.value += "E = " + E + "\n"; E = E - 20.0 * (Math.floor(E / 20.0)); //document.debug.log.value += "Efixed = " + E + "\n"; E = E / (24 * 60); //document.debug.log.value += "Eday = " + E + "\n"; return E; } // Following lines are from the original index.html /* You may notice that a variety of array variables logically local to functions are declared globally here. In JavaScript, construction of an array variable from source code occurs as the code is interpreted. Making these variables pseudo-globals permits us to avoid overhead constructing and disposing of them in each call on the function in which whey are used. */ var J0000 = 1721424.5; // Julian date of Gregorian epoch: 0000-01-01 var J1970 = 2440587.5; // Julian date at Unix epoch: 1970-01-01 var JMJD = 2400000.5; // Epoch of Modified Julian Date system var J1900 = 2415020.5; // Epoch (day 1) of Excel 1900 date system (PC) var J1904 = 2416480.5; // Epoch (day 0) of Excel 1904 date system (Mac) var NormLeap = new Array("Normales Jahr", "Schaltjahr"); /* WEEKDAY_BEFORE -- Return Julian date of given weekday (0 = Sunday) in the seven days ending on jd. */ function weekday_before(weekday, jd) { return jd - jwday(jd - weekday); } /* SEARCH_WEEKDAY -- Determine the Julian date for: weekday Day of week desired, 0 = Sunday jd Julian date to begin search direction 1 = next weekday, -1 = last weekday offset Offset from jd to begin search */ function search_weekday(weekday, jd, direction, offset) { return weekday_before(weekday, jd + (direction * offset)); } // Utility weekday functions, just wrappers for search_weekday function nearest_weekday(weekday, jd) { return search_weekday(weekday, jd, 1, 3); } function next_weekday(weekday, jd) { return search_weekday(weekday, jd, 1, 7); } function next_or_current_weekday(weekday, jd) { return search_weekday(weekday, jd, 1, 6); } function previous_weekday(weekday, jd) { return search_weekday(weekday, jd, -1, 1); } function previous_or_current_weekday(weekday, jd) { return search_weekday(weekday, jd, 1, 0); } function TestSomething() { } // LEAP_GREGORIAN -- Is a given year in the Gregorian calendar a leap year ? function leap_gregorian(year) { return ((year % 4) == 0) && (!(((year % 100) == 0) && ((year % 400) != 0))); } // GREGORIAN_TO_JD -- Determine Julian day number from Gregorian calendar date var GREGORIAN_EPOCH = 1721425.5; function gregorian_to_jd(year, month, day) { return (GREGORIAN_EPOCH - 1) + (365 * (year - 1)) + Math.floor((year - 1) / 4) + (-Math.floor((year - 1) / 100)) + Math.floor((year - 1) / 400) + Math.floor((((367 * month) - 362) / 12) + ((month <= 2) ? 0 : (leap_gregorian(year) ? -1 : -2) ) + day); } // JD_TO_GREGORIAN -- Calculate Gregorian calendar date from Julian day function jd_to_gregorian(jd) { var wjd, depoch, quadricent, dqc, cent, dcent, quad, dquad, yindex, dyindex, year, yearday, leapadj; wjd = Math.floor(jd - 0.5) + 0.5; depoch = wjd - GREGORIAN_EPOCH; quadricent = Math.floor(depoch / 146097); dqc = mod(depoch, 146097); cent = Math.floor(dqc / 36524); dcent = mod(dqc, 36524); quad = Math.floor(dcent / 1461); dquad = mod(dcent, 1461); yindex = Math.floor(dquad / 365); year = (quadricent * 400) + (cent * 100) + (quad * 4) + yindex; if (!((cent == 4) || (yindex == 4))) { year++; } yearday = wjd - gregorian_to_jd(year, 1, 1); leapadj = ((wjd < gregorian_to_jd(year, 3, 1)) ? 0 : (leap_gregorian(year) ? 1 : 2) ); month = Math.floor((((yearday + leapadj) * 12) + 373) / 367); day = (wjd - gregorian_to_jd(year, month, 1)) + 1; return new Array(year, month, day); } // ISO_TO_JULIAN -- Return Julian day of given ISO year, week, and day function n_weeks(weekday, jd, nthweek) { var j = 7 * nthweek; if (nthweek > 0) { j += previous_weekday(weekday, jd); } else { j += next_weekday(weekday, jd); } return j; } function iso_to_julian(year, week, day) { return day + n_weeks(0, gregorian_to_jd(year - 1, 12, 28), week); } // JD_TO_ISO -- Return array of ISO (year, week, day) for Julian day function jd_to_iso(jd) { var year, week, day; year = jd_to_gregorian(jd - 3)[0]; if (jd >= iso_to_julian(year + 1, 1, 1)) { year++; } week = Math.floor((jd - iso_to_julian(year, 1, 1)) / 7) + 1; day = jwday(jd); if (day == 0) { day = 7; } return new Array(year, week, day); } // ISO_DAY_TO_JULIAN -- Return Julian day of given ISO year, and day of year function iso_day_to_julian(year, day) { return (day - 1) + gregorian_to_jd(year, 1, 1); } // JD_TO_ISO_DAY -- Return array of ISO (year, day_of_year) for Julian day function jd_to_iso_day(jd) { var year, day; year = jd_to_gregorian(jd)[0]; day = Math.floor(jd - gregorian_to_jd(year, 1, 1)) + 1; return new Array(year, day); } /* PAD -- Pad a string to a given length with a given fill character. */ function pad(str, howlong, padwith) { var s = str.toString(); while (s.length < howlong) { s = padwith + s; } return s; } // JULIAN_TO_JD -- Determine Julian day number from Julian calendar date var JULIAN_EPOCH = 1721423.5; function leap_julian(year) { return (year % 4) == ((year > 0) ? 0 : 3); } function julian_to_jd(year, month, day) { /* Adjust negative common era years to the zero-based notation we use. */ if (year < 1) { year++; } /* Algorithm as given in Meeus, Astronomical Algorithms, Chapter 7, page 61 */ if (month <= 2) { year--; month += 12; } return ((Math.floor((365.25 * (year + 4716))) + Math.floor((30.6001 * (month + 1))) + day) - 1524.5); } // JD_TO_JULIAN -- Calculate Julian calendar date from Julian day function jd_to_julian(td) { var z, a, alpha, b, c, d, e, year, month, day; td += 0.5; z = Math.floor(td); a = z; b = a + 1524; c = Math.floor((b - 122.1) / 365.25); d = Math.floor(365.25 * c); e = Math.floor((b - d) / 30.6001); month = Math.floor((e < 14) ? (e - 1) : (e - 13)); year = Math.floor((month > 2) ? (c - 4716) : (c - 4715)); day = b - d - Math.floor(30.6001 * e); /* If year is less than 1, subtract one to convert from a zero based date system to the common era system in which the year -1 (1 B.C.E) is followed by year 1 (1 C.E.). */ if (year < 1) { year--; } return new Array(year, month, day); } // HEBREW_TO_JD -- Determine Julian day from Hebrew date var HEBREW_EPOCH = 347995.5; // Is a given Hebrew year a leap year ? function hebrew_leap(year) { return mod(((year * 7) + 1), 19) < 7; } // How many months are there in a Hebrew year (12 = normal, 13 = leap) function hebrew_year_months(year) { return hebrew_leap(year) ? 13 : 12; } // Test for delay of start of new year and to avoid // Sunday, Wednesday, and Friday as start of the new year. function hebrew_delay_1(year) { var months, days, parts; months = Math.floor(((235 * year) - 234) / 19); parts = 12084 + (13753 * months); day = (months * 29) + Math.floor(parts / 25920); if (mod((3 * (day + 1)), 7) < 3) { day++; } return day; } // Check for delay in start of new year due to length of adjacent years function hebrew_delay_2(year) { var last, present, next; last = hebrew_delay_1(year - 1); present = hebrew_delay_1(year); next = hebrew_delay_1(year + 1); return ((next - present) == 356) ? 2 : (((present - last) == 382) ? 1 : 0); } // How many days are in a Hebrew year ? function hebrew_year_days(year) { return hebrew_to_jd(year + 1, 7, 1) - hebrew_to_jd(year, 7, 1); } // How many days are in a given month of a given year function hebrew_month_days(year, month) { // First of all, dispose of fixed-length 29 day months if (month == 2 || month == 4 || month == 6 || month == 10 || month == 13) { return 29; } // If it's not a leap year, Adar has 29 days if (month == 12 && !hebrew_leap(year)) { return 29; } // If it's Heshvan, days depend on length of year if (month == 8 && !(mod(hebrew_year_days(year), 10) == 5)) { return 29; } // Similarly, Kislev varies with the length of year if (month == 9 && (mod(hebrew_year_days(year), 10) == 3)) { return 29; } // Nope, it's a 30 day month return 30; } // Finally, wrap it all up into... function hebrew_to_jd(year, month, day) { var jd, mon, months; months = hebrew_year_months(year); jd = HEBREW_EPOCH + hebrew_delay_1(year) + hebrew_delay_2(year) + day + 1; if (month < 7) { for (mon = 7; mon <= months; mon++) { jd += hebrew_month_days(year, mon); } for (mon = 1; mon < month; mon++) { jd += hebrew_month_days(year, mon); } } else { for (mon = 7; mon < month; mon++) { jd += hebrew_month_days(year, mon); } } return jd; } /* JD_TO_HEBREW -- Convert Julian date to Hebrew date This works by making multiple calls to the inverse function, and is this very slow. */ function jd_to_hebrew(jd) { var year, month, day, i, count, first; jd = Math.floor(jd) + 0.5; count = Math.floor(((jd - HEBREW_EPOCH) * 98496.0) / 35975351.0); year = count - 1; for (i = count; jd >= hebrew_to_jd(i, 7, 1); i++) { year++; } first = (jd < hebrew_to_jd(year, 1, 1)) ? 7 : 1; month = first; for (i = first; jd > hebrew_to_jd(year, i, hebrew_month_days(year, i)); i++) { month++; } day = (jd - hebrew_to_jd(year, month, 1)) + 1; return new Array(year, month, day); } /* EQUINOXE_A_PARIS -- Determine Julian day and fraction of the September equinox at the Paris meridian in a given Gregorian year. */ function equinoxe_a_paris(year) { var equJED, equJD, equAPP, equParis, dtParis; // September equinox in dynamical time equJED = equinox(year, 2); // Correct for delta T to obtain Universal time equJD = equJED - (deltat(year) / (24 * 60 * 60)); // Apply the equation of time to yield the apparent time at Greenwich equAPP = equJD + equationOfTime(equJED); /* Finally, we must correct for the constant difference between the Greenwich meridian and that of Paris, 2°20'15" to the East. */ dtParis = (2 + (20 / 60.0) + (15 / (60 * 60.0))) / 360; equParis = equAPP + dtParis; return equParis; } /* PARIS_EQUINOXE_JD -- Calculate Julian day during which the September equinox, reckoned from the Paris meridian, occurred for a given Gregorian year. */ function paris_equinoxe_jd(year) { var ep, epg; ep = equinoxe_a_paris(year); epg = Math.floor(ep - 0.5) + 0.5; return epg; } /* ANNEE_DE_LA_REVOLUTION -- Determine the year in the French revolutionary calendar in which a given Julian day falls. Returns an array of two elements: [0] Année de la Révolution [1] Julian day number containing equinox for this year. */ var FRENCH_REVOLUTIONARY_EPOCH = 2375839.5; function annee_da_la_revolution(jd) { var guess = jd_to_gregorian(jd)[0] - 2, lasteq, nexteq, adr; lasteq = paris_equinoxe_jd(guess); while (lasteq > jd) { guess--; lasteq = paris_equinoxe_jd(guess); } nexteq = lasteq - 1; while (!((lasteq <= jd) && (jd < nexteq))) { lasteq = nexteq; guess++; nexteq = paris_equinoxe_jd(guess); } adr = Math.round((lasteq - FRENCH_REVOLUTIONARY_EPOCH) / TropicalYear) + 1; return new Array(adr, lasteq); } /* JD_TO_FRENCH_REVOLUTIONARY -- Calculate date in the French Revolutionary calendar from Julian day. The five or six "sansculottides" are considered a thirteenth month in the results of this function. */ function jd_to_french_revolutionary(jd) { var an, mois, decade, jour, adr, equinoxe; jd = Math.floor(jd) + 0.5; adr = annee_da_la_revolution(jd); an = adr[0]; equinoxe = adr[1]; mois = Math.floor((jd - equinoxe) / 30) + 1; jour = (jd - equinoxe) % 30; decade = Math.floor(jour / 10) + 1; jour = (jour % 10) + 1; return new Array(an, mois, decade, jour); } /* FRENCH_REVOLUTIONARY_TO_JD -- Obtain Julian day from a given French Revolutionary calendar date. */ function french_revolutionary_to_jd(an, mois, decade, jour) { var adr, equinoxe, guess, jd; guess = FRENCH_REVOLUTIONARY_EPOCH + (TropicalYear * ((an - 1) - 1)); adr = new Array(an - 1, 0); while (adr[0] < an) { adr = annee_da_la_revolution(guess); guess = adr[1] + (TropicalYear + 2); } equinoxe = adr[1]; jd = equinoxe + (30 * (mois - 1)) + (10 * (decade - 1)) + (jour - 1); return jd; } // LEAP_ISLAMIC -- Is a given year a leap year in the Islamic calendar ? function leap_islamic(year) { return (((year * 11) + 14) % 30) < 11; } // ISLAMIC_TO_JD -- Determine Julian day from Islamic date var ISLAMIC_EPOCH = 1948439.5; var ISLAMIC_WEEKDAYS = new Array("al-'ahad", "al-'ithnayn", "ath-thalatha'", "al-'arb`a'", "al-khamis", "al-jum`a", "as-sabt"); function islamic_to_jd(year, month, day) { return (day + Math.ceil(29.5 * (month - 1)) + (year - 1) * 354 + Math.floor((3 + (11 * year)) / 30) + ISLAMIC_EPOCH) - 1; } // JD_TO_ISLAMIC -- Calculate Islamic date from Julian day function jd_to_islamic(jd) { var year, month, day; jd = Math.floor(jd) + 0.5; year = Math.floor(((30 * (jd - ISLAMIC_EPOCH)) + 10646) / 10631); month = Math.min(12, Math.ceil((jd - (29 + islamic_to_jd(year, 1, 1))) / 29.5) + 1); day = (jd - islamic_to_jd(year, month, 1)) + 1; return new Array(year, month, day); } // LEAP_PERSIAN -- Is a given year a leap year in the Persian calendar ? function leap_persian(year) { return ((((((year - ((year > 0) ? 474 : 473)) % 2820) + 474) + 38) * 682) % 2816) < 682; } // PERSIAN_TO_JD -- Determine Julian day from Persian date var PERSIAN_EPOCH = 1948320.5; var PERSIAN_WEEKDAYS = new Array("Yekshanbeh", "Doshanbeh", "Seshhanbeh", "Chaharshanbeh", "Panjshanbeh", "Jomeh", "Shanbeh"); function persian_to_jd(year, month, day) { var epbase, epyear; epbase = year - ((year >= 0) ? 474 : 473); epyear = 474 + mod(epbase, 2820); return day + ((month <= 7) ? ((month - 1) * 31) : (((month - 1) * 30) + 6) ) + Math.floor(((epyear * 682) - 110) / 2816) + (epyear - 1) * 365 + Math.floor(epbase / 2820) * 1029983 + (PERSIAN_EPOCH - 1); } // JD_TO_PERSIAN -- Calculate Persian date from Julian day function jd_to_persian(jd) { var year, month, day, depoch, cycle, cyear, ycycle, aux1, aux2, yday; jd = Math.floor(jd) + 0.5; depoch = jd - persian_to_jd(475, 1, 1); cycle = Math.floor(depoch / 1029983); cyear = mod(depoch, 1029983); if (cyear == 1029982) { ycycle = 2820; } else { aux1 = Math.floor(cyear / 366); aux2 = mod(cyear, 366); ycycle = Math.floor(((2134 * aux1) + (2816 * aux2) + 2815) / 1028522) + aux1 + 1; } year = ycycle + (2820 * cycle) + 474; if (year <= 0) { year--; } yday = (jd - persian_to_jd(year, 1, 1)) + 1; month = (yday <= 186) ? Math.ceil(yday / 31) : Math.ceil((yday - 6) / 30); day = (jd - persian_to_jd(year, month, 1)) + 1; return new Array(year, month, day); } // MAYAN_COUNT_TO_JD -- Determine Julian day from Mayan long count var MAYAN_COUNT_EPOCH = 584282.5; function mayan_count_to_jd(baktun, katun, tun, uinal, kin) { return MAYAN_COUNT_EPOCH + (baktun * 144000) + (katun * 7200) + (tun * 360) + (uinal * 20) + kin; } // JD_TO_MAYAN_COUNT -- Calculate Mayan long count from Julian day function jd_to_mayan_count(jd) { var d, baktun, katun, tun, uinal, kin; d = jd - MAYAN_COUNT_EPOCH; baktun = Math.floor(d / 144000); d = mod(d, 144000); katun = Math.floor(d / 7200); d = mod(d, 7200); tun = Math.floor(d / 360); d = mod(d, 360); uinal = Math.floor(d / 20); kin = mod(d, 20); return new Array(baktun, katun, tun, uinal, kin); } // JD_TO_MAYAN_HAAB -- Determine Mayan Haab "month" and day from Julian day var MAYAN_HAAB_MONTHS = new Array("Pop", "Uo", "Zip", "Zotz", "Tzec", "Xul", "Yaxkin", "Mol", "Chen", "Yax", "Zac", "Ceh", "Mac", "Kankin", "Muan", "Pax", "Kayab", "Cumku", "Uayeb"); function jd_to_mayan_haab(jd) { var lcount, day; lcount = jd - MAYAN_COUNT_EPOCH; day = mod(lcount + 8 + ((18 - 1) * 20), 365); return new Array (Math.floor(day / 20) + 1, mod(day, 20)); } // JD_TO_MAYAN_TZOLKIN -- Determine Mayan Tzolkin "month" and day from Julian day var MAYAN_TZOLKIN_MONTHS = new Array("Imix", "Ik", "Akbal", "Kan", "Chicchan", "Cimi", "Manic", "Lamat", "Muluc", "Oc", "Chuen", "Eb", "Ben", "Ix", "Men", "Cib", "Caban", "Etznab", "Cauac", "Ahau"); function jd_to_mayan_tzolkin(jd) { var lcount = jd - MAYAN_COUNT_EPOCH; return new Array (amod(lcount + 20, 20), amod(lcount + 4, 13)); } // BAHAI_TO_JD -- Determine Julian day from Bahai date var BAHAI_EPOCH = 2394646.5; var BAHAI_WEEKDAYS = new Array("Jamál", "Kamál", "Fidál", "Idál", "Istijlál", "Istiqlál", "Jalál"); function bahai_to_jd(major, cycle, year, month, day) { var gy; gy = (361 * (major - 1)) + (19 * (cycle - 1)) + (year - 1) + jd_to_gregorian(BAHAI_EPOCH)[0]; return gregorian_to_jd(gy, 3, 20) + (19 * (month - 1)) + ((month != 20) ? 0 : (leap_gregorian(gy + 1) ? -14 : -15)) + day; } // JD_TO_BAHAI -- Calculate Bahai date from Julian day function jd_to_bahai(jd) { var major, cycle, year, month, day, gy, bstarty, bys, days, bld; jd = Math.floor(jd) + 0.5; gy = jd_to_gregorian(jd)[0]; bstarty = jd_to_gregorian(BAHAI_EPOCH)[0]; bys = gy - (bstarty + (((gregorian_to_jd(gy, 1, 1) <= jd) && (jd <= gregorian_to_jd(gy, 3, 20))) ? 1 : 0)); major = Math.floor(bys / 361) + 1; cycle = Math.floor(mod(bys, 361) / 19) + 1; year = mod(bys, 19) + 1; days = jd - bahai_to_jd(major, cycle, year, 1, 1); bld = bahai_to_jd(major, cycle, year, 20, 1); month = (jd >= bld) ? 20 : (Math.floor(days / 19) + 1); day = (jd + 1) - bahai_to_jd(major, cycle, year, month, 1); return new Array(major, cycle, year, month, day); } // INDIAN_CIVIL_TO_JD -- Obtain Julian day for Indian Civil date var INDIAN_CIVIL_WEEKDAYS = new Array( "ravivara", "somavara", "mangalavara", "budhavara", "brahaspativara", "sukravara", "sanivara"); function indian_civil_to_jd(year, month, day) { var Caitra, gyear, leap, start, jd, m; gyear = year + 78; leap = leap_gregorian(gyear); // Is this a leap year ? start = gregorian_to_jd(gyear, 3, leap ? 21 : 22); Caitra = leap ? 31 : 30; if (month == 1) { jd = start + (day - 1); } else { jd = start + Caitra; m = month - 2; m = Math.min(m, 5); jd += m * 31; if (month >= 8) { m = month - 7; jd += m * 30; } jd += day - 1; } return jd; } // JD_TO_INDIAN_CIVIL -- Calculate Indian Civil date from Julian day function jd_to_indian_civil(jd) { var Caitra, Saka, greg, greg0, leap, start, year, yday, mday; Saka = 79 - 1; // Offset in years from Saka era to Gregorian epoch start = 80; // Day offset between Saka and Gregorian jd = Math.floor(jd) + 0.5; greg = jd_to_gregorian(jd); // Gregorian date for Julian day leap = leap_gregorian(greg[0]); // Is this a leap year? year = greg[0] - Saka; // Tentative year in Saka era greg0 = gregorian_to_jd(greg[0], 1, 1); // JD at start of Gregorian year yday = jd - greg0; // Day number (0 based) in Gregorian year Caitra = leap ? 31 : 30; // Days in Caitra this year if (yday < start) { // Day is at the end of the preceding Saka year year--; yday += Caitra + (31 * 5) + (30 * 3) + 10 + start; } yday -= start; if (yday < Caitra) { month = 1; day = yday + 1; } else { mday = yday - Caitra; if (mday < (31 * 5)) { month = Math.floor(mday / 31) + 2; day = (mday % 31) + 1; } else { mday -= 31 * 5; month = Math.floor(mday / 30) + 7; day = (mday % 30) + 1; } } return new Array(year, month, day); } /* updateFromGregorian -- Update all calendars from Gregorian. "Why not Julian date?" you ask. Because starting from Gregorian guarantees we're already snapped to an integral second, so we don't get roundoff errors in other calendars. */ function updateFromGregorian() { var j, year, mon, mday, hour, min, sec, weekday, julcal, hebcal, islcal, hmindex, utime, isoweek, may_countcal, mayhaabcal, maytzolkincal, bahcal, frrcal, indcal, isoday, xgregcal; year = new Number(document.gregorian.year.value); mon = document.gregorian.month.selectedIndex; mday = new Number(document.gregorian.day.value); hour = min = sec = 0; hour = new Number(document.gregorian.hour.value); min = new Number(document.gregorian.min.value); sec = new Number(document.gregorian.sec.value); // Update Julian day j = gregorian_to_jd(year, mon + 1, mday) + (Math.floor(sec + 60 * (min + 60 * hour) + 0.5) / 86400.0); // Update day of week in Gregorian box weekday = jwday(j); // Update leap year status in Gregorian box // Update Julian Calendar julcal = jd_to_julian(j); // Update Hebrew Calendar hebcal = jd_to_hebrew(j); hmindex = hebcal[1]; if (hmindex == 12 && !hebrew_leap(hebcal[0])) { hmindex = 14; } // Update Mayan Calendars may_countcal = jd_to_mayan_count(j); mayhaabcal = jd_to_mayan_haab(j); maytzolkincal = jd_to_mayan_tzolkin(j); document.mayancount.tzolkin.value = "" + maytzolkincal[1] + " " + MAYAN_TZOLKIN_MONTHS[maytzolkincal[0] - 1]; document.mayancount.ton.value = maytzolkincal[1]; document.mayancount.siegel.value=MAYAN_TZOLKIN_MONTHS[maytzolkincal[0] - 1]; // Update Bahai Calendar bahcal = jd_to_bahai(j); document.bahai.kull_i_shay.value = bahcal[0]; document.bahai.vahid.value = bahcal[1]; document.bahai.year.selectedIndex = bahcal[2] - 1; document.bahai.month.selectedIndex = bahcal[3] - 1; document.bahai.day.selectedIndex = bahcal[4] - 1; document.bahai.weekday.value = BAHAI_WEEKDAYS[weekday]; document.bahai.leap.value = NormLeap[leap_gregorian(year) ? 1 : 0]; // Bahai uses same leap rule as Gregorian // Update Indian Civil Calendar indcal = jd_to_indian_civil(j); document.indiancivilcalendar.year.value = indcal[0]; document.indiancivilcalendar.month.selectedIndex = indcal[1] - 1; document.indiancivilcalendar.day.value = indcal[2]; document.indiancivilcalendar.weekday.value = INDIAN_CIVIL_WEEKDAYS[weekday]; document.indiancivilcalendar.leap.value = NormLeap[leap_gregorian(indcal[0] + 78) ? 1 : 0]; // Update French Republican Calendar frrcal = jd_to_french_revolutionary(j); document.french.an.value = frrcal[0]; document.french.mois.selectedIndex = frrcal[1] - 1; document.french.decade.selectedIndex = frrcal[2] - 1; document.french.jour.selectedIndex = ((frrcal[1] <= 12) ? frrcal[3] : (frrcal[3] + 11)) - 1; // Update Gregorian serial number if (document.gregserial != null) { document.gregserial.day.value = j - J0000; } // Update Excel 1900 and 1904 day serial numbers document.excelserial1900.day.value = (j - J1900) + 1 + /* Microsoft marching morons thought 1900 was a leap year. Adjust dates after 1900-02-28 to compensate for their idiocy. */ ((j > 2415078.5) ? 1 : 0) ; document.excelserial1904.day.value = j - J1904; // Update Unix time() utime = (j - J1970) * (60 * 60 * 24 * 1000); document.unixtime.time.value = Math.round(utime / 1000); // Update ISO Week isoweek = jd_to_iso(j); document.isoweek.year.value = isoweek[0]; document.isoweek.week.value = isoweek[1]; document.isoweek.day.value = isoweek[2]; // Update ISO Day isoday = jd_to_iso_day(j); document.isoday.year.value = isoday[0]; document.isoday.day.value = isoday[1]; } // calcGregorian -- Perform calculation starting with a Gregorian date function calcGregorian() { updateFromGregorian(); } // calcJulian -- Perform calculation starting with a Julian date function calcJulian() { var j, time; j = new Number(document.julianday.day.value); date = jd_to_gregorian(j); time = jhms(j); document.gregorian.year.value = date[0]; document.gregorian.month.value = date[1] - 1; document.gregorian.day.value = date[2]; document.gregorian.hour.value = pad(time[0], 2, " "); document.gregorian.min.value = pad(time[1], 2, "0"); document.gregorian.sec.value = pad(time[2], 2, "0"); updateFromGregorian(); } // setJulian -- Set Julian date and update all calendars function setJulian(j) { document.julianday.day.value = new Number(j); calcJulian(); } // calcModifiedJulian -- Update from Modified Julian day function calcModifiedJulian() { setJulian((new Number(document.modifiedjulianday.day.value)) + JMJD); } // calcJulianCalendar -- Update from Julian calendar function calcJulianCalendar() { setJulian(julian_to_jd((new Number(document.juliancalendar.year.value)), document.juliancalendar.month.selectedIndex + 1, (new Number(document.juliancalendar.day.value)))); } // calcHebrew -- Update from Hebrew calendar function calcHebrew() { setJulian(hebrew_to_jd((new Number(document.hebrew.year.value)), document.hebrew.month.selectedIndex + 1, (new Number(document.hebrew.day.value)))); } // calcIslamic -- Update from Islamic calendar function calcIslamic() { setJulian(islamic_to_jd((new Number(document.islamic.year.value)), document.islamic.month.selectedIndex + 1, (new Number(document.islamic.day.value)))); } // calcPersian -- Update from Persian calendar function calcPersian() { setJulian(persian_to_jd((new Number(document.persian.year.value)), document.persian.month.selectedIndex + 1, (new Number(document.persian.day.value)))); } // calcMayanCount -- Update from the Mayan Long Count function calcMayanCount() { setJulian(mayan_count_to_jd((new Number(document.mayancount.baktun.value)), (new Number(document.mayancount.katun.value)), (new Number(document.mayancount.tun.value)), (new Number(document.mayancount.uinal.value)), (new Number(document.mayancount.kin.value)))); } // calcBahai -- Update from Bahai calendar function calcBahai() { setJulian(bahai_to_jd((new Number(document.bahai.kull_i_shay.value)), (new Number(document.bahai.vahid.value)), document.bahai.year.selectedIndex + 1, document.bahai.month.selectedIndex + 1, document.bahai.day.selectedIndex + 1)); } // calcIndianCivilCalendar -- Update from Indian Civil Calendar function calcIndianCivilCalendar() { setJulian(indian_civil_to_jd( (new Number(document.indiancivilcalendar.year.value)), document.indiancivilcalendar.month.selectedIndex + 1, (new Number(document.indiancivilcalendar.day.value)))); } // calcFrench -- Update from French Republican calendar function calcFrench() { var decade, j, mois; j = document.french.jour.selectedIndex; decade = document.french.decade.selectedIndex; mois = document.french.mois.selectedIndex; /* If the currently selected day is one of the sansculottides, adjust the index to be within that period and force the decade to zero and the month to 12, designating the intercalary interval. */ if (j > 9) { j -= 11; decade = 0; mois = 12; } /* If the selected month is the pseudo-month of the five or six sansculottides, ensure that the decade is 0 and the day number doesn't exceed six. To avoid additional overhead, we don't test whether a day number of 6 is valid for this year, but rather simply permit it to wrap into the first day of the following year if this is a 365 day year. */ if (mois == 12) { decade = 0; if (j > 5) { j = 0; } } setJulian(french_revolutionary_to_jd((new Number(document.french.an.value)), mois + 1, decade + 1, j + 1)); } // calcGregSerial -- Update from Gregorian serial day number function calcGregSerial() { setJulian((new Number(document.gregserial.day.value)) + J0000); } // calcExcelSerial1900 -- Perform calculation starting with an Excel 1900 serial date function calcExcelSerial1900() { var d = new Number(document.excelserial1900.day.value); /* Idiot Kode Kiddies didn't twig to the fact (proclaimed in 1582) that 1900 wasn't a leap year, so every Excel day number in every database on Earth which represents a date subsequent to February 28, 1900 is off by one. Note that there is no acknowledgement of this betrayal or warning of its potential consequences in the Excel help file. Thank you so much Mister Talking Paper Clip. Some day we're going to celebrate your extinction like it was February 29 ... 1900. */ if (d > 60) { d--; } setJulian((d - 1) + J1900); } // calcExcelSerial1904 -- Perform calculation starting with an Excel 1904 serial date function calcExcelSerial1904() { setJulian((new Number(document.excelserial1904.day.value)) + J1904); } // calcUnixTime -- Update from specified Unix time() value function calcUnixTime() { var t = new Number(document.unixtime.time.value); setJulian(J1970 + (t / (60 * 60 * 24))); } // calcIsoWeek -- Update from specified ISO year, week, and day function calcIsoWeek() { var year = new Number(document.isoweek.year.value), week = new Number(document.isoweek.week.value), day = new Number(document.isoweek.day.value); setJulian(iso_to_julian(year, week, day)); } // calcIsoDay -- Update from specified ISO year and day of year function calcIsoDay() { var year = new Number(document.isoday.year.value), day = new Number(document.isoday.day.value); setJulian(iso_day_to_julian(year, day)); }