/*
****************************************************************************
JavaScript sunrise/sunset calculator
Author: Jeff Conrad
Date: 19 October 1998
Revision History:
1.9 12 Feb 2005 Updated magnetic declinations
1.8 17 Jun 2004 Simplified Maxalt(); changed to include
refraction; revised date display; revised day
length calculation; updated magnetic
declinations; fixed DST w/southern latitudes
1.7 14 Jun 2003 Increased MAX_CALC from 53 to 366 days
1.6 14 Jun 2003 Updated magnetic declinations
1.5 22 Oct 2002 Updated magnetic declinations
1.4 19 Oct 2000 Removed timer
1.3 2 Aug 2000 Revised structure; added Sun position
1.2 27 Jul 2000 Added location database, help file, display of
azimuths in true or magnetic north
****************************************************************************
Copyright 1998-2004 Jeff Conrad
****************************************************************************
*/
var
// constants
F_CIRCUMPOLAR = 9999,
F0_NO_PHENOM = 999, // no phenomenon--set value
F_NO_PHENOM = 99, // no phenomenon--test value
D_to_R = Math.PI / 180, // degrees to radians
D_to_MSEC = 24 * 3600 * 1e3, // days to msec
// indices to places array
NAME = 0,
LAT = 1,
LONG = 2,
TZ = 3,
DST = 4, // uses DST? yes=1, no=0
MAGDEC = 5,
// calculation type
TIMES = 0,
POSITION = 1;
// HTML tags
var
VSPACE = "
",
SP = " ",
SP2 = SP + SP,
SP4 = SP2 + SP2,
PAD4 = " ",
PAD8 = PAD4 + PAD4,
BR = "
",
B = "",
BE = "",
EM = "",
EME = "",
HT = "\t",
LF = "\n",
TABLE_START = "";
TABLE_START2 = "";
THD = "",
THDE = "",
TBD = "",
TBDE = "",
TR = PAD4 + "",
TR_R = PAD4 + '
',
TRE = PAD4 + "
",
TH11 = PAD8 + "",
TH21 = PAD8 + " | ",
TH12 = PAD8 + " | ",
TH8 = PAD8 + " | ",
THE = " | ",
TD = PAD8 + "",
TD_C = PAD8 + ' | ',
TD_L = PAD8 + ' | ',
TD_N = PAD8 + ' | ',
TDE = " | ";
// HTML 4 named character entities
if (navigator.appName == "Netscape")
var MINUS = "–"; // fake with en dash
else
var MINUS = "−";
var MDASH = "—";
var day_of_week = [ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" ];
var months = [ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
];
var monthdays = [
// 1 2 3 4 5 6 7 8 9 10 11 12
[ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ],
[ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ]
];
// magnetic declinations as of 12 February 2005
var places = [
[ "invalid" ],
[ "Alturas, CA", "41:29:14", "120:32:28", 8, 1, 15.55 ],
[ "Baker, CA", "35:15:54", "116:04:25", 8, 1, 13.02 ],
[ "Bakersfield, CA", "35:22:24", "119:01:05", 8, 1, 13.66 ],
[ "Barstow, CA", "34:53:55", "117:01:19", 8, 1, 13.15 ],
[ "Bishop, CA", "37:21:49", "118:23:38", 8, 1, 14.02 ],
[ "Blythe, CA", "33:36:37", "114:35:46", 8, 1, 12.32 ],
[ "Borrego Springs, CA", "33:15:21", "116:22:27", 8, 1, 12.65 ],
[ "Crescent City, CA", "41:45:22", "124:12:04", 8, 1, 16.25 ],
[ "Death Valley NP", "36:27:26", "116:51:55", 8, 1, 13.48 ],
[ "Eureka, CA", "40:48:08", "124:09:47", 8, 1, 15.96 ],
[ "Fort Bragg, CA", "39:26:45", "123:48:14", 8, 1, 15.51 ],
[ "Fresno, CA", "36:44:52", "119:46:16", 8, 1, 14.14 ],
[ "Gorman, CA", "34:47:46", "118:51:06", 8, 1, 13.49 ],
[ "Kings Canyon NP", "36:47:27", "118:40:10", 8, 1, 13.94 ],
[ "Lee Vining, CA", "37:57:27", "119:07:15", 8, 1, 14.32 ],
[ "Lone Pine, CA", "36:36:22", "118:03:43", 8, 1, 13.77 ],
[ "Los Angeles, CA", "34:03:08", "118:14:35", 8, 1, 13.20 ],
[ "Los Osos, CA", "35:18:40", "120:49:53", 8, 1, 13.96 ],
[ "Mojave, CA", "35:03:09", "118:10:23", 8, 1, 13.42 ],
[ "Monterey, CA", "36:36:01", "121:53:38", 8, 1, 14.45 ],
[ "Needles, CA", "34:50:53", "114:36:47", 8, 1, 12.58 ],
[ "Nevada City, CA", "39:15:42", "121:00:54", 8, 1, 15.03 ],
[ "Orick, CA", "41:17:13", "124:03:31", 8, 1, 16.09 ],
[ "Redding, CA", "40:35:12", "122:23:28", 8, 1, 15.63 ],
[ "Sacramento, CA", "38:34:54", "121:29:35", 8, 1, 14.92 ],
[ "San Diego, CA", "32:42:55", "117:09:22", 8, 1, 12.69 ],
[ "San Francisco, CA", "37:46:30", "122:25:05", 8, 1, 14.85 ],
[ "San Luis Obispo, CA", "35:16:58", "120:39:32", 8, 1, 13.92 ],
[ "Santa Barbara, CA", "34:25:15", "119:41:49", 8, 1, 13.55 ],
[ "Santa Rosa, CA", "38:26:26", "122:42:47", 8, 1, 15.07 ],
[ "Susanville, CA", "40:24:59", "120:39:07", 8, 1, 15.28 ],
[ "Truckee, CA", "39:19:41", "120:10:55", 8, 1, 14.89 ],
[ "Twentynine Palms, CA", "34:08:08", "116:03:11", 8, 1, 12.77 ],
[ "Yosemite NP, CA", "37:44:43", "119:35:50", 8, 1, 14.36 ],
[ "Yreka, CA", "41:44:08", "122:37:59", 8, 1, 16.01 ],
[ "invalid" ],
[ "invalid" ],
[ "Albuquerque, NM", "35:05:04", "106:39:04", 7, 1, 9.96 ],
[ "Anchorage, AK", "61:13:05", "149:54:00", 9, 1, 20.58 ],
[ "Atlanta, GA", "33:44:56", "84:23:17", 5, 1, -4.02 ],
[ "Augusta, ME", "44:18:38", "69:46:48", 5, 1, -16.80 ],
[ "Austin, TX", "30:16:01", "97:44:34", 6, 1, 5.34 ],
[ "Barrow, AK", "71:17:26", "156:47:20", 9, 1, 20.84 ],
[ "Boise, ID", "43:36:49", "116:12:11", 7, 1, 15.07 ],
[ "Boston, MA", "42:21:30", "71:03:37", 5, 1, -15.44 ],
[ "Chicago, IL", "41:51:00", "87:39:00", 6, 1, -3.01 ],
[ "Cincinnati, OH", "39:09:43", "84:27:25", 5, 1, -5.09 ],
[ "Dallas, TX", "32:47:00", "96:48:00", 6, 1, 4.78 ],
[ "Denver, CO", "39:44:21", "104:59:02", 7, 1, 9.73 ],
[ "Detroit, MI", "42:19:53", "83:02:45", 5, 1, -7.09 ],
[ "El Paso, TX", "31:45:31", "106:29:10", 7, 1, 9.50 ],
[ "Fairbanks, AK", "64:50:16", "147:42:58", 9, 1, 22.85 ],
[ "Hernandez, NM", "36:03:46", "106:07:08", 7, 1, 9.85 ],
[ "Honolulu, HI", "21:18:25", "157:51:29", 10, 0, 9.98 ],
[ "Jackson, WY", "43:28:48", "110:45:43", 7, 1, 13.05 ],
[ "Juneau, AK", "58:18:07", "134:25:12", 9, 1, 23.21 ],
[ "Kalispell, MT", "48:11:45", "114:18:43", 7, 1, 15.68 ],
[ "Lynchburg, TN", "35:16:59", "86:22:27", 6, 1, -2.79 ],
[ "Miami, FL", "25:46:26", "80:11:38", 5, 1, -5.46 ],
[ "Minneapolis, MN", "44:58:48", "93:15:49", 6, 1, 1.37 ],
[ "Moab, UT", "38:34:24", "109:32:56", 7, 1, 11.65 ],
[ "Navy Town, AK", "52:50:27", "-173:10:32", 10, 0, 1.13 ],
[ "New York, NY", "40:42:51", "74:00:23", 5, 1, -13.22 ],
[ "Nome, AK", "64:30:04", "165:24:22", 9, 1, 13.87 ],
[ "Page, AZ", "36:54:31", "111:28:23", 7, 0, 12.06 ],
[ "Phoenix, AZ", "33:26:54", "112:04:23", 7, 0, 11.62 ],
[ "Pittsburgh, PA", "40:26:26", "79:59:46", 5, 1, -8.98 ],
[ "Portland, OR", "45:31:25", "122:40:30", 8, 1, 17.20 ],
[ "Rapid City, SD", "44:04:50", "103:13:52", 7, 1, 9.13 ],
[ "Reno, NV", "39:31:47", "119:48:47", 8, 1, 14.87 ],
[ "Rochester, NY", "43:09:17", "77:36:57", 5, 1, -11.66 ],
[ "Saint Louis, MO", "38:37:38", "90:11:52", 6, 1, -0.31 ],
[ "Salt Lake City, UT", "40:45:39", "111:53:24", 7, 1, 12.95 ],
[ "Seattle, WA", "47:36:23", "122:19:52", 8, 1, 17.84 ],
[ "Sedona, AZ", "34:52:11", "111:45:36", 7, 0, 11.78 ],
[ "Washington, DC", "38:53:42", "77:02:12", 5, 1, -10.68 ],
[ "invalid" ],
[ "invalid" ],
[ "Calgary, AB", "51:02:28", "114:03:39", 7, 1, 16.45 ],
[ "Edmonton, AB", "53:32:44", "113:30:18", 7, 1, 17.03 ],
[ "Guadalajara, Mexico", "20:40", "103:21", 6, 0, 7.57 ],
[ "Halifax, NS", "44:39:52", "63:36:30", 4, 1, -19.02 ],
[ "Mexico City, Mexico", "19:26", "99:08", 6, 0, 6.10 ],
[ "Monterrey, Mexico", "25:41", "100:19", 6, 0, 6.56 ],
[ "Montreal, PQ", "45:31:22", "73:34:00", 5, 1, -15.32 ],
[ "Ottawa, ON", "45:25:34", "75:42:04", 5, 1, -13.91 ],
[ "Regina, SK", "50:26:54", "104:36:38", 6, 1, 10.72 ],
[ "San Lucas, Mexico", "22:54", "109:54", 7, 0, 9.48 ],
[ "Toronto, ON", "43:39:51", "79:21:26", 5, 1, -10.53 ],
[ "Vancouver, BC", "49:15:45", "123:06:00", 8, 1, 18.59 ],
[ "Winnipeg, MB", "49:53:57", "97:08:57", 6, 1, 4.33 ],
[ "invalid" ],
[ "invalid" ],
[ "Bogota, Columbia", "4:37", "74:04", 5, 0, -5.53 ],
[ "Buenos Aires, Argentina", "-34:37", "58:22", 3, 0, -6.96 ],
[ "Caracas, Venezuela", "10:30", "66:55", 4, 0, -11.12 ],
[ "La Paz, Bolivia", "-16:30", "68:09", 4, 0, -5.58 ],
[ "Lima, Peru", "-12:04", "77:03", 5, 0, 0.18 ],
[ "Punta Arenas, Chile", "-53:09", "70:56", 4, 1, 14.27 ],
[ "Rio de Janeiro, Brazil", "-22:54", "43:13", 3, 1, -21.52 ],
[ "Santiago, Chile", "-33:28", "70:39", 4, 1, 3.62 ],
[ "invalid" ],
[ "invalid" ],
[ "Amsterdam, Netherlands", "52:23", "-4:53", -1, 1, -0.70 ],
[ "Athens, Greece", "37:58", "-23:44", -2, 1, 3.21 ],
[ "Berlin, Germany", "52:32", "-13:25", -1, 1, 2.08 ],
[ "Bern, Switzerland", "46:57", "-7:27", -1, 1, 0.48 ],
[ "Copenhagen, Denmark", "55:41", "-12:34", -1, 1, 1.83 ],
[ "Helsinki, Finland", "60:10", "-24:57", -2, 1, 6.99 ],
[ "London, UK", "51:30", "0:06", 0, 1, -2.40 ],
[ "Madrid, Spain", "40:26", "3:43", -1, 1, -2.38 ],
[ "Munich, Germany", "48:08", "-11:34", -1, 1, 1.54 ],
[ "Moscow, Russia", "55:45", "-37:42", -3, 1, 9.58 ],
[ "Oslo, Norway", "59:55", "-10:46", -1, 1, 1.09 ],
[ "Paris, France", "48:50", "-2:20", -1, 1, -1.20 ],
[ "Reykjavik, Iceland", "64:08", "21:54", 0, 0, -17.38 ],
[ "Rome, Italy", "41:53", "-12:30", -1, 1, 1.69 ],
[ "Stockholm, Sweden", "59:20", "-18:02", -1, 1, 4.11 ],
[ "Vienna, Austria", "48:13", "-16:21", -1, 1, 2.71 ],
[ "Warsaw, Poland", "52:15", "-21:00", -1, 1, 4.22 ],
[ "invalid" ],
[ "invalid" ],
[ "Baghdad, Iraq", "33:20", "-44:25", -3, 1, 3.78 ],
[ "Beijing, China", "39:54", "-116:28", -8, 0, -6.20 ],
[ "Islamabad, Pakistan", "33:43", "-73:04", -5, 0, 2.07 ],
[ "Istanbul, Turkey", "41:01", "-28:57", -2, 1, 4.18 ],
[ "Jakarta, Indonesia", "-6:11", "-106:50", -7, 0, 0.76 ],
[ "Jerusalem, Israel", "31:47", "-35:13", -2, 1, 3.61 ],
[ "Kabul, Afghanistan", "34:32", "-69:08", -4, 0, 2.55 ],
[ "Manila, Philippines", "14:35", "-120:59", -8, 0, -1.27 ],
[ "Mecca, Saudi Arabia", "21:26", "-39:49", -3, 0, 2.65 ],
[ "Mumbai, India", "18:57", "-72:50", -5, 0, -0.88 ],
[ "New Delhi, India", "28:38", "-77:12", -5, 0, 0.68 ],
[ "Seoul, Korea", "37:33", "-127:02", -9, 0, -7.76 ],
[ "Shanghai, China", "39:14", "-121:29", -8, 0, -7.32 ],
[ "Singapore, Singapore", "1:18", "-103:51", -8, 0, 0.28 ],
[ "Taipei, Taiwan", "25:02", "-121:31", -8, 0, -3.64 ],
[ "Tehran, Iran", "35:42", "-51:25", -3, 0, 3.97 ],
[ "Tokyo, Japan", "35:35", "-139:45", -9, 0, -6.89 ],
[ "invalid" ],
[ "invalid" ],
[ "Addis Ababa, Ethiopia", "9:01", "-38:45", -3, 0, 1.62 ],
[ "Antananarivo, Madagascar", "-18:55", "-47:32", -3, 0, -15.08 ],
[ "Cairo, Egypt", "30:02", "-31:15", -2, 1, 3.26 ],
[ "Capetown, South Africa", "-33:55", "-18:26", -2, 0, -24.04 ],
[ "Casablanca, Morocco", "33:36", "-7:37", 0, 0, 0.55 ],
[ "Dar es Salaam, Tanzania", "-6:49", "-39:17", -3, 0, -2.33 ],
[ "Dakar, Senegal", "14:40", "17:26", 0, 0, -8.93 ],
[ "Nairobi, Kenya", "-1:17", "-36:49", -3, 0, 0.03 ],
[ "Tripoli, Libya", "32:52", "-13:11", -1, 0, 1.44 ],
[ "Windhoek, Namibia", "-22:34", "-17:05", -2, 0, -13.43 ],
[ "invalid" ],
[ "invalid" ],
[ "Brisbane, Australia", "-27:28", "-153:02", -10, 1, 11.12 ],
[ "Perth, Australia", "-31:57:09", "-115:51:24", -8, 1, -1.78 ],
[ "Sydney, Australia", "-33:52:00", "-151:12:00", -10, 1, 12.61 ],
[ "invalid" ],
[ "invalid" ],
[ "Auckland, New Zealand", "-36:50", "-174:45", -12, 1, 19.34 ],
[ "Grytviken, South Georgia", "-54:16", "36:31", 2, 0, -6.99 ],
];
var place_name;
function isleap(year)
{
if ((year) % 4 == 0 && (year) % 100 != 0 || (year) % 400 == 0)
return (1);
else
return (0);
}
// ************* Number and String methods **********
Number.prototype.SetRange = function(y)
{
var x = this;
x %= y;
if (x < 0)
x += y;
return (x);
}
// convert decimal angle to dd:mm
Number.prototype.toDMS = function()
{
var
angle = this,
degrees,
minutes,
seconds,
sign = 1;
if (angle < 0.0) {
angle = -angle;
sign = -1;
}
degrees = Math.floor(angle)
minutes = Math.round((angle - degrees) * 60.0);
if (minutes > 59.0) {
minutes = 0.0;
degrees++;
}
return ((sign == -1 ? "-" : "")
+ degrees + ":" + (minutes < 10 ? "0" : "") + minutes);
}
String.prototype.DMSto = function()
{
var
angle = this,
d_angle,
sign,
temparr = angle.split(":");
if (angle.indexOf("-") != -1)
sign = -1;
else
sign = 1;
if(sign == -1)
temparr[0] *= -1;
d_angle = (temparr[0] - 0);
if (temparr.length > 1) // minutes given
d_angle += ((temparr[1] - 0) / 60);
if (temparr.length > 2) // seconds given
d_angle += ((temparr[2] - 0) / 3600);
return sign * d_angle;
}
Math.rnd = function(x, d)
{
var multiplier = Math.pow(10, d);
return Math.round(x * multiplier) / multiplier;
}
// ************* Date properties and methods ********
Date.prototype.JD1970 = 2440587.50; // JD of 0h UT 1 Jan 1970
// set 0h LCT
Date.prototype.setZeroHours = function()
{
this.setHours(0);
this.setMinutes(0);
this.setSeconds(0);
this.setMilliseconds(0);
}
// Julian Day Number
Date.prototype.getJulian = function()
{
// JD of 0h UT
return (
Math.floor(
this.JD1970 + this.getTime() / D_to_MSEC
- this.getTimezoneOffset() / 60 / 24
) + 0.5
);
}
// *************** Place object *****************************
function Place(place)
{
if (arguments.length) {
this.name = place[NAME];
this.latitude = String(place[LAT]).DMSto();
this.longitude = String(place[LONG]).DMSto();
this.timezone = Number(place[TZ]);
this.use_dst = Number(place[DST]);
this.mag_dec = String(place[MAGDEC]).DMSto();
}
}
Place.prototype.timezones = [
// 0 1 2 3 4 5 6 7 8
"UT", "", "", "", "Atlantic", "Eastern", "Central", "Mountain", "Pacific",
// 9 10
"Alaska/Yukon", "Hawaii/Aleutian"
];
Place.prototype.tznames = [
// 0 1 2 3 4 5 6 7 8 9 10
[ "UT", "", "", "", "AST", "EST", "CST", "MST", "PST", "YST", "HST" ],
[ "BST", "", "", "", "ADT", "EDT", "CDT", "MDT", "PDT", "YDT", "HDT" ]
];
Place.prototype.getTimezone = function()
{
var
tz_int = Math.floor(this.timezone);
if (this.timezones[tz_int])
return (this.timezones[tz_int]);
else
return (null);
}
Place.prototype.get_tzname = function()
{
var
daylite = this.dst_offset ? 1 : 0,
tz_int = Math.floor(this.timezone),
tzname;
/* show British and North American time zone names */
if (tz_int >= 0 && tz_int < this.tznames[0].length && this.latitude > 15.0
&& this.tznames[daylite][tz_int] != "")
tzname = this.tznames[daylite][tz_int];
/* show UT */
else if (tz_int == 0 && daylite == 0)
tzname = this.tznames[daylite][tz_int];
/* just show standard vs. daylight saving time */
else if (daylite)
tzname = "DST";
else
tzname = "STD";
return tzname;
}
// determine daylight saving status
// DST rules for the computer's location are applied to all locations,
// so "dst_offset" isn't really as general as it appears
Place.prototype.is_dst = function(CalcDate)
{
var
dst_offset = homeloc.std_TZ_offset - CalcDate.getTimezoneOffset() / 60,
hemisign = this.latitude * homeloc.dst_offset;
if (homeloc.dst_offset == 0) // no way to determine DST status
this.dst_offset = 0; // can only compute standard times
else if (hemisign < 0 && dst_offset == 0) // location and computer in opp hemispheres
this.dst_offset = homeloc.dst_offset; // turn on computer's DST
else if (hemisign < 0) // DST in effect for computer
this.dst_offset = 0; // turn off DST
else // location and computer in same hemisphere;
this.dst_offset = dst_offset; // apply computer's current DST
return(this.dst_offset * 1);
}
// get time offset from UT
Place.prototype.get_t_offset = function(CalcDate)
{
var t_offset = this.timezone;
if (this.use_dst == 1)
t_offset -= this.is_dst(CalcDate);
this.t_offset = t_offset;
return (t_offset * 1);
}
// get the DST offset for the computer's location
function get_std_TZ_offset()
{
var
SummerSolstice = new Date("21 Jun 2000"),
WinterSolstice = new Date("21 Dec 2000"),
summer_tOffset = SummerSolstice.getTimezoneOffset() / 60,
winter_tOffset = WinterSolstice.getTimezoneOffset() / 60;
if (winter_tOffset < summer_tOffset) // southern hemisphere
homeloc.std_TZ_offset = summer_tOffset;
else // northern hemisphere
homeloc.std_TZ_offset = winter_tOffset;
// positive in northern hemisphere
homeloc.dst_offset = winter_tOffset - summer_tOffset;
delete SummerSolstice, WinterSolstice;
}
// ********************* Sun position object ***************************
// constructor
function SunPos()
{
;
}
// calculate UT of rise/set/transit
// returns: UT or +/- infinity if no phenomenon
SunPos.prototype.getTime = function(jday, loc, type)
{
var
cos_H, // cosine of local hour angle
longitude = loc.longitude,
ntrys,
sign,
sin_h, // sine of altitude
t,
ut = 12.0 + loc.timezone, // approximate local noon
ut0 = -1;
var
sin_lat = Math.sin(loc.latitude * D_to_R),
cos_lat = Math.cos(loc.latitude * D_to_R);
switch(type) {
case "M":
case "R":
sign = 1;
break;
case "T":
sign = 0;
break;
case "S":
case "E":
sign = -1;
break;
}
switch(type) {
case "M":
case "E":
sin_h = Math.sin(-6 * D_to_R);
break;
default:
sin_h = Math.sin(-5/6 * D_to_R);
}
// hack to make things work at a few places (e.g., Navy Town, AK)
// near the date line
if (loc.timezone > 0 && longitude < 0)
longitude += 360;
else if (loc.timezone < 0 && longitude > 0)
longitude -= 360;
ut0 = 0;
ntrys = 0;
while (Math.abs(ut - ut0) > 0.001) {
if (++ntrys > 10)
break;
ut0 = ut;
// calculate position
this.calcPos(jday, ut);
// calculate hour angle
if (type == "T")
cos_H = 1; // transit at H = 0
else
cos_H = (sin_h - sin_lat * Math.sin(this.declination)) /
(cos_lat * Math.cos(this.declination))
if (cos_H > 1) // circumpolar; never rises
t = 0;
else if (cos_H < -1) // circumpolar; never sets
t = 180;
else
t = Math.acos(cos_H) / D_to_R;
ut = ut0 - (this.gha - longitude + sign * t) / 15.0;
}
this.declination /= D_to_R;
if (type != "T") {
if (cos_H > 1)
ut = Number.NEGATIVE_INFINITY; // circumpolar; never rises
else if (cos_H < -1)
ut = Number.POSITIVE_INFINITY; // circumpolar; never sets
else if (ntrys > 10)
ut = F0_NO_PHENOM; // phenomenon does not occur
}
return (ut);
}
// length of time Sun is above horizon
SunPos.prototype.getDayLen = function(rise, set)
{
var day;
// handle set before rise
if (Math.abs(rise) < F_CIRCUMPOLAR && Math.abs(set) < F_CIRCUMPOLAR) {
if (rise < set)
day = set - rise;
else
day = 24 - (rise - set);
}
else if (rise >= F_CIRCUMPOLAR || set >= F_CIRCUMPOLAR)
day = 24;
else if (rise <= -F_CIRCUMPOLAR || set <= -F_CIRCUMPOLAR)
day = 0;
return day;
}
// Low-precision Sun ephemeris from the Explanatory Supplement to the
// Astronomical Almanac, rev. ed., Chapter 9
//
// Greenwich Hour Angle (GHA) in degrees
// declination in radians
SunPos.prototype.calcPos = function(jday, ut)
{
var
J2000 = 2451545.0; // JD of 12:00 UT 1 Jan 2000
var
anomaly, // mean anomaly
eq_time, // equation of time
lambda, // ecliptic longitude
long_mean, // mean longitude
obliquity, // obliquity of the ecliptic
T; // centuries since J2000
T = (jday + ut / 24.0 - J2000) / 36525.0;
long_mean = (280.46 + 36000.77 * T).SetRange(360);
anomaly = (357.528 + 35999.05 * T).SetRange(360.0) * D_to_R;
lambda = (long_mean + 1.915 * Math.sin(anomaly)
+ 0.02 * Math.sin(2 * anomaly)) * D_to_R;
lambda = lambda.SetRange(2.0 * Math.PI);
obliquity = (23.4393 - 0.013 * T) * D_to_R;
eq_time = (-1.915 * Math.sin(anomaly)
-0.02 * Math.sin(2.0 * anomaly)
+2.466 * Math.sin(2.0 * lambda)
-0.053 * Math.sin(4.0 * lambda)) * D_to_R;
this.gha = 15.0 * ut - 180.0 + eq_time / D_to_R;
this.declination = Math.asin(Math.sin(obliquity) * Math.sin(lambda));
}
SunPos.prototype.calcAltAz = function(loc)
{
var
lha = (this.gha - loc.longitude) * D_to_R, // Local hour angle
decl = this.declination;
lat = loc.latitude * D_to_R;
this.azimuth = Math.atan2(
Math.sin(lha),
Math.cos(lha) * Math.sin(lat) - Math.tan(decl) * Math.cos(lat)
) / D_to_R + 180;
this.altitude = Math.asin(
Math.sin(lat) * Math.sin(decl)
+ Math.cos(lat) * Math.cos(decl) * Math.cos(lha)
) / D_to_R;
}
// compute apparent altitude from true altitude
SunPos.prototype.getAppAlt = function()
{
var alt = this.altitude;
// avoid singularity
if (alt < -5.0016 || alt > 89.891)
return alt;
else
return alt + 1.02 / Math.tan((alt + 10.3 / (alt + 5.11)) * D_to_R) / 60.0;
}
// compute azimuth at time of rise/set
SunPos.prototype.getAzimuth = function(loc, altitude, type)
{
var
cos_az,
azimuth;
altitude *= D_to_R;
latitude = loc.latitude * D_to_R;
declination = this.declination * D_to_R;
cos_az = (
Math.sin(declination) - Math.sin(latitude) * Math.sin(altitude))
/ (Math.cos(latitude) * Math.cos(altitude)
);
if (cos_az > 1.0)
azimuth = 0.0;
else if (cos_az < -1.0)
azimuth = 180.0;
else
azimuth = Math.acos(cos_az) / D_to_R;
return (type == "R" ? azimuth : 360 - azimuth).SetRange(360);
}
// compute altitude of body at transit
SunPos.prototype.getMaxalt = function(loc)
{
this.altitude = 90.0 - Math.abs(this.declination - loc.latitude);
return this.getAppAlt();
}
function initialize_form()
{
var form = document.Options;
if (form.status.value == 0) // initial load
reset_form(form);
}
function reset_date(form)
{
var Today = new Date();
Today.setZeroHours();
form.StartDay.selectedIndex = Today.getDate() - 1;
form.StartYear.value = Today.getFullYear();
form.StartMonth.selectedIndex = Today.getMonth();
form.EndDay.selectedIndex = form.StartDay.selectedIndex;
form.EndMonth.selectedIndex = form.StartMonth.selectedIndex;
form.EndYear.value = form.StartYear.value;
form.CalcDay.selectedIndex = Today.getDate() - 1;
form.CalcYear.value = Today.getFullYear();
form.CalcMonth.selectedIndex = Today.getMonth();
form.end[0].checked = true;
form.status.value = 1; // mark as loaded
delete Today;
}
function reset_form(form)
{
form.reset();
reset_date(form);
loc = new Place();
}
function clear_name()
{
place_name = "Unknown";
}
// set latitude and longitude to values for the selected location
function copy_lat_long(form)
{
var ndx = form.city.selectedIndex;
place_name = places[ndx][NAME];
if ((latitude = places[ndx][LAT].DMSto()) < 0) {
form.latitude.value = (-latitude).toDMS();
form.lat_sign.selectedIndex = 1;
}
else {
form.latitude.value = latitude.toDMS();
form.lat_sign.selectedIndex = 0;
}
if ((longitude = places[ndx][LONG].DMSto()) < 0) {
form.longitude.value = (-longitude).toDMS();
form.long_sign.selectedIndex = 1;
}
else {
form.longitude.value = longitude.toDMS();
form.long_sign.selectedIndex = 0;
}
if (places[ndx][TZ]);
// can't handle fractional hour offsets
form.timezone.options.selectedIndex = Math.round(places[ndx][TZ]) + 13;
form.use_dst.options.selectedIndex = places[ndx][DST];
if (places[ndx][MAGDEC] < 0) {
form.magdec.value = (-places[ndx][MAGDEC]).toDMS();
form.magdec_sign.selectedIndex = 0;
}
else {
form.magdec.value = (places[ndx][MAGDEC]).toDMS();
form.magdec_sign.selectedIndex = 1;
}
}
function check_start_day(form)
{
var
day = form.StartDay.selectedIndex + 1,
ndx = form.StartMonth.selectedIndex,
year = form.StartYear.value,
maxdays = monthdays[isleap(year)][ndx];
if (day > maxdays)
form.StartDay.selectedIndex = maxdays - 1;
}
function check_end_day(form)
{
var
day = form.EndDay.selectedIndex + 1,
ndx = form.EndMonth.selectedIndex,
year = form.EndYear.value,
maxdays = monthdays[isleap(year)][ndx];
if (day > maxdays)
form.EndDay.selectedIndex = maxdays - 1;
}
function check_calc_day(form)
{
var
day = form.CalcDay.selectedIndex + 1,
ndx = form.CalcMonth.selectedIndex,
year = form.CalcYear.value,
maxdays = monthdays[isleap(year)][ndx];
if (day > maxdays)
form.CalcDay.selectedIndex = maxdays - 1;
}
function check_year(field)
{
if (isNaN(field.value)) {
alert("Bad value (" + field.value + ") for year");
field.focus();
field.select();
}
}
// ensure that date offset is nonnegative
function check_nonnegative(field)
{
if (isNaN(field.value) || field.value < 0) {
alert("Nonnegative number required");
field.focus();
field.select();
}
}
// ensure that value is positive
function check_value_positive(value)
{
if (isNaN(value - 0) || value <= 0)
alert("Positive number required");
}
function help()
{
window.location.href = "SunCalcHelp.htm";
return true;
}
var
std_TZ_offset;
flags = new Object(),
homeloc = new Object(), // home location
s_pos = new Object();
function calculate()
{
var
params = document.Options; // save some typing
var
MAX_CALC = 366,
calc_type,
n_calcs,
sun = new Object(),
place = new Array(),
start_day, // days since 0h UT 1 January 1970
end_day, // days since 0h UT 1 January 1970
offset,
calc_step = params.step.value - 0,
time_zone,
ndx;
var Today = new Date();
var copyright = BR + SP2 + "SunCalc © " + Today.getFullYear() + " Jeff Conrad";
delete Today;
get_std_TZ_offset();
// ************ set location *************************
if (params.loc_type[0].checked == true) { // look up location
ndx = params.city.selectedIndex;
if (places[ndx][NAME] == "invalid") {
alert(
"Please select a location"
);
return;
}
else if (params.city.options[ndx].text != places[ndx][NAME]) {
alert(
"Location lookup error:"
+ "\n" + params.city.options[ndx].text
+ "\n vs."
+ "\n" + places[ndx][NAME]
);
return;
}
else
place = places[ndx];
}
else { // just set lat/long
if (place_name)
place[NAME] = place_name;
else
place[NAME] = "Unknown";
if (isNaN(place[LAT] = params.latitude.value.DMSto())) {
alert("Invalid latitude (" + params.latitude.value + ")\n"
+ "Format: dd:[mm[:ss]] or dd.nn");
params.latitude.focus();
params.latitude.select();
return;
}
else if (Math.abs(params.latitude.value) > 90) {
alert("Invalid latitude (" + params.latitude.value + ")\n"
+ "Range is -90 to 90");
return;
}
ndx = params.lat_sign.selectedIndex;
place[LAT] *= params.lat_sign.options[ndx].value;
if (isNaN((place[LONG] = params.longitude.value.DMSto()))) {
alert("Invalid longitude (" + params.longitude.value + ")\n"
+ "Format: dd:[mm[:ss]] or dd.nn");
return;
}
else if (Math.abs(place[LONG]) > 180) {
alert("Invalid longitude (" + params.longitude.value + ")\n"
+ "Range is -180 to 180");
return;
}
ndx = params.long_sign.selectedIndex;
place[LONG] *= params.long_sign.options[ndx].value;
ndx = params.timezone.selectedIndex;
var timezone = params.timezone.options[ndx].value;
if (timezone == "")
place[TZ] = Math.round(place[LONG] / 15);
else if (isNaN((place[TZ] = timezone * 1))) {
alert("Invalid time zone (" + timezone + ")");
return;
}
else if (Math.abs(place[TZ]) > 12) {
alert("Invalid time zone (" + timezone + ")");
return;
}
ndx = params.use_dst.selectedIndex;
place[DST] = params.use_dst.options[ndx].value;
if (isNaN((place[MAGDEC] = params.magdec.value.DMSto()))) {
alert("Invalid magnetic declination (" + params.magdec.value + ")\n"
+ "Format: dd:[mm[:ss]] or dd.nn");
return;
}
else if (Math.abs(place[MAGDEC]) > 180) {
alert("Invalid magnetic declination (" + params.magdec.value + ")\n"
+ "Range is -180 to 180");
return;
}
ndx = params.magdec_sign.selectedIndex;
place[MAGDEC] *= params.magdec_sign.options[ndx].value;
}
loc = new Place(place);
ndx = params.magnorth.selectedIndex;
flags.show_mag_north = params.magnorth.options[ndx].value;
if (params.calc_type[0].checked == true) {
// **************** set dates (0h LCT) ********************
calc_type = TIMES;
StartDate = new Date(params.StartYear.value,
params.StartMonth.selectedIndex,
params.StartDay.selectedIndex + 1);
start_day = StartDate.getTime() / D_to_MSEC;
if (params.end[1].checked == true) { // offset to start date
if (isNaN((offset = params.DateOffset.value - 0)) || offset < 0) {
alert("Bad value (" + offset + ") for date offset");
return;
}
ndx = params.o_units.selectedIndex;
end_day = start_day + offset * params.o_units.options[ndx].value;
}
else { // calendar date
EndDate = new Date(params.EndYear.value,
params.EndMonth.selectedIndex,
params.EndDay.selectedIndex + 1);
end_day = EndDate.getTime() / D_to_MSEC;
// ensure that end_date differs from start_date by an
// integral number of days
offset = Math.round(end_day - start_day)
end_day = start_day + offset;
}
if (end_day < start_day) {
params.EndYear.value = params.StartYear.value;
params.EndMonth.selectedIndex = params.StartMonth.selectedIndex;
params.EndDay.selectedIndex = params.StartDay.selectedIndex;
EndDate = new Date(params.EndYear.value,
params.EndMonth.selectedIndex,
params.EndDay.selectedIndex + 1);
end_day = EndDate.getTime() / D_to_MSEC;
}
ndx = params.s_units.selectedIndex;
calc_step *= params.s_units.options[ndx].value;
if (((n_calcs = end_day - start_day) / calc_step) > MAX_CALC) {
alert("Too many calculations (" + n_calcs + ")--maximum is " + MAX_CALC);
return;
}
}
else {
// **************** set date (0h LCT) ********************
calc_type = POSITION;
StartDate = new Date(params.CalcYear.value,
params.CalcMonth.selectedIndex,
params.CalcDay.selectedIndex + 1);
start_day = end_day = StartDate.getTime() / D_to_MSEC;
ndx = params.time_step.selectedIndex;
time_step = params.time_step.options[ndx].value;
}
if (navigator.appName.indexOf("Netscape") != -1) {
var
wid = 0.85 * screen.availWidth,
ht = 0.85 * screen.availHeight,
xpos = 0.02 * screen.availWidth,
ypos = 0.02 * screen.availHeight;
ResultsWindow = window.open(
"",
"Results",
"height=" + ht
+ ",width=" + wid
+ ",resizable=1,menubar=1,toolbar=0,statusbar=1,scrollbars=1"
);
ResultsWindow.moveTo(xpos, ypos);
ResultsWindow.focus();
var d = ResultsWindow.document;
}
else
var d = document;
d.close();
d.writeln("");
d.writeln("");
d.writeln('');
d.writeln("Sunrise/Sunset Results");
d.writeln("");
d.writeln("");
d.writeln(SP + B + "Location: " + loc.name + BE + BR);
if (loc.latitude < 0)
d.writeln(SP, B, "Latitude: ", (-loc.latitude).toDMS(), " S", BE, BR);
else
d.writeln(SP, B, "Latitude: ", loc.latitude.toDMS(), " N", BE, BR);
if (loc.longitude < 0)
d.writeln(SP, B, "Longitude: ", (-loc.longitude).toDMS(), " E", BE, BR);
else
d.writeln(SP, B, "Longitude: ", loc.longitude.toDMS(), " W", BE, BR);
d.write(SP, B, "Time Zone: ", loc.timezone);
if ((time_zone = loc.getTimezone()))
d.write(" (", time_zone + ")");
d.writeln(BE + BR);
if (loc.mag_dec < 0)
d.writeln(SP, B, "Magnetic Declination: ", (-loc.mag_dec).toDMS(), " W", BE, BR);
else
d.writeln(SP, B, "Magnetic Declination: ", loc.mag_dec.toDMS(), " E", BE, BR);
d.writeln(SP, "Azimuths Relative to ", B,
(flags.show_mag_north == true ? "Magnetic" : "True"),
" North" + BE + BR);
// start = new Date(); // for timing program
calc_times(start_day, end_day, calc_step, sun, loc, d)
if (calc_type == POSITION)
calc_positions(start_day, time_step, sun, loc, d)
d.writeln(copyright);
// end = new Date();
// d.writeln("(", (end.getTime() - start.getTime()), " msec)", BR);
if (navigator.appName.indexOf("Netscape") != -1) {
d.writeln("");
}
d.close();
}
// calculate Sun azimuths and altitudes between sunrise and sunset
function calc_positions(calc_day, time_step, sun, loc, d)
{
var
altitude,
calc_time,
spos = new SunPos(), // Sun position
CalcDate = new Date((calc_day) * D_to_MSEC),
t_offset = loc.get_t_offset(CalcDate),
jday = CalcDate.getJulian();
// don't bother if the Sun never rises
if (sun.rise < -F_CIRCUMPOLAR && sun.set < -F_CIRCUMPOLAR)
return;
if (sun.rise > F_CIRCUMPOLAR)
sun.rise = 0;
if (sun.set > F_CIRCUMPOLAR)
sun.set = 24;
d.writeln(BR);
d.writeln(TABLE_START2);
d.writeln(THD);
d.writeln(TR);
d.writeln(TH11 + "Time" + THE);
d.writeln(TH11 + (flags.show_mag_north == true? "Azimuth*" : "Azimuth") + THE);
d.writeln(TH11 + "Altitude" + THE);
d.writeln(TH11 + "Shadow", BR, "Length" + THE);
d.writeln(TRE);
d.writeln(THDE);
d.writeln(TBD);
time_step /= 60;
var
start_time = Math.ceil(sun.rise / time_step) * time_step;
end_time = Math.floor(sun.set / time_step) * time_step;
// if set precedes rise, show the entire day
if (start_time > end_time) {
start_time = 0;
end_time = 24;
}
var nn = 0;
for (calc_time = start_time; calc_time <= end_time; calc_time += time_step) {
if (++nn > 500)
break; // prevent an infinite loop
spos.calcPos(jday, calc_time + t_offset);
spos.calcAltAz(loc);
if (flags.show_mag_north == true)
spos.azimuth = (spos.azimuth - loc.mag_dec).SetRange(360);
d.writeln(TR);
d.write(TD_C);
if (time_step < 0.5 && Math.rnd(calc_time, 3) % 1 == 0)
d.write(B);
if (calc_time < 0)
d.write((calc_time + 24).toDMS(), MINUS);
else if (calc_time > 24)
d.write((calc_time - 24).toDMS(), "+");
else
d.write(calc_time.toDMS());
if (time_step < 0.5 && Math.rnd(calc_time, 3) % 1 == 0)
d.write(BE);
d.writeln(TDE);
d.writeln(TD_C, Math.rnd(spos.azimuth, 1), TDE);
if ((altitude = Math.rnd(spos.getAppAlt(), 1)) < 0)
d.writeln(TD_C, MINUS, -altitude, TDE);
else
d.writeln(TD_C, altitude, TDE);
if (altitude > 0)
d.writeln(TD_C, Math.rnd(1 / Math.tan(altitude * D_to_R), 2), TDE);
else
d.writeln(TD_C, MDASH, TDE);
d.writeln(TRE);
}
d.writeln(TBDE);
d.writeln(TABLE_END);
delete CalcDate;
}
function calc_times(start_day, end_day, calc_step, sun, loc, d)
{
d.writeln(BR);
d.writeln(TABLE_START);
d.writeln(THD);
d.writeln(TR);
d.writeln(TH21 + "Day" + THE);
d.writeln(TH21 + "Date" + THE);
d.writeln(TH21 + "Dawn" + THE);
d.writeln(TH21 + "Rise" + THE);
d.writeln(TH21 + "Transit" + THE);
d.writeln(TH21 + "Set" + THE);
d.writeln(TH21 + "Dusk" + THE);
d.writeln(TH21 + "Day" + BR + "Length" + THE);
d.writeln(TH12 + (flags.show_mag_north == true? "Azimuth*" : "Azimuth") + THE);
d.writeln(TH21 + "Max" + BR + "Alt" + THE);
d.writeln(TRE);
d.writeln(TR);
d.writeln(TH11 + "Rise" + THE);
d.writeln(TH11 + "Set" + THE);
d.writeln(TRE);
d.writeln(THDE);
d.writeln(TBD);
var
h = -5/6, // standard altitude for rise/set
hours,
jday, // Julian day number (JD)
spos = new SunPos(), // Sun position
dst_offset,
t_offset;
var dst_offset = homeloc.dst_offset;
for (calc_day = start_day; calc_day <= end_day + 1.001 / 24; calc_day += calc_step) {
// CalcDate is at 0h local time to get JD
var CalcDate = new Date((calc_day) * D_to_MSEC);
jday = CalcDate.getJulian();
delete CalcDate;
// CalcDate is at 12h local time to determine DST
// and ensure correct date display
var CalcDate = new Date((calc_day + 0.5) * D_to_MSEC);
t_offset = loc.get_t_offset(CalcDate);
sun.dawn = spos.getTime(jday, loc, "M") - t_offset;
sun.rise = spos.getTime(jday, loc, "R") - t_offset;
sun.transit = spos.getTime(jday, loc, "T") - t_offset;
sun.set = spos.getTime(jday, loc, "S") - t_offset;
sun.dusk = spos.getTime(jday, loc, "E") - t_offset;
sun.day = spos.getDayLen(sun.rise, sun.set);
sun.az_rise = spos.getAzimuth(loc, h, "R");
sun.az_set = spos.getAzimuth(loc, h, "S");
sun.maxalt = spos.getMaxalt(loc);
if (flags.show_mag_north == true) {
sun.az_rise = (sun.az_rise - loc.mag_dec).SetRange(360);
sun.az_set = (sun.az_set - loc.mag_dec).SetRange(360);
}
output_times(CalcDate, sun, d);
delete CalcDate;
}
d.writeln(TBDE);
d.writeln(TABLE_END);
}
function output_times(cdate, s, d)
{
var
NO_PHENOM = MDASH, // phenomenon does not occur [em dash]
ABOVE = "****", // circumpolar; never sets
BELOW = "-----", // circumpolar; never rises
LIGHT = "/////", // twilight never ends
DARK = "==="; // twilight never begins
d.writeln(TR_R);
d.writeln(TD_L + day_of_week[cdate.getDay()] + TDE);
d.writeln(
TD_N + ((day = cdate.getDate()) < 10 ? SP : "")
+ day
+ " " + months[cdate.getMonth()]
+ " " + cdate.getFullYear()
+ " (" + loc.get_tzname() + ")"
+ TDE
);
if (s.dawn <= -F_CIRCUMPOLAR)
d.writeln(TD_C, DARK, TDE);
else if (s.dawn >= F_CIRCUMPOLAR)
d.writeln(TD_C, LIGHT, TDE);
else if (s.dawn > F_NO_PHENOM)
d.writeln(TD_C, NO_PHENOM, TDE);
else if (s.dawn < 0) // previous day
d.writeln(TD_C, (s.dawn + 24).toDMS() + MINUS, TDE);
else
d.writeln(TD_C, s.dawn.toDMS(), TDE);
// sunrise
if (s.rise <= -F_CIRCUMPOLAR)
d.writeln(TD_C, BELOW, TDE);
else if (s.rise >= F_CIRCUMPOLAR)
d.writeln(TD_C, ABOVE, TDE);
else if (s.rise > F_NO_PHENOM)
d.writeln(TD_C, NO_PHENOM, TDE);
else if (s.rise < 0) // previous day
d.writeln(TD_C, (s.rise + 24).toDMS() + MINUS, TDE);
else
d.writeln(TD_C + s.rise.toDMS() + TDE);
if (s.transit < 0)
d.writeln(TD_C, (s.transit + 24).toDMS() + MINUS, TDE);
else if (s.transit > 24)
d.writeln(TD_C, (s.transit - 24).toDMS() + "+", TDE);
else
d.writeln(TD_C, s.transit.toDMS(), TDE);
// sunset
if (s.set <= -F_CIRCUMPOLAR)
d.writeln(TD_C, BELOW, TDE);
else if (s.set >= F_CIRCUMPOLAR)
d.writeln(TD_C, ABOVE, TDE);
else if (s.set > F_NO_PHENOM)
d.writeln(TD_C, NO_PHENOM, TDE);
else if (s.set > 24) // next day
d.writeln(TD_C, (s.set - 24).toDMS() + "+", TDE);
else
d.writeln(TD_C, s.set.toDMS(), TDE);
if (s.dusk <= -F_CIRCUMPOLAR)
d.writeln(TD_C, DARK, TDE);
else if (s.dusk >= F_CIRCUMPOLAR)
d.writeln(TD_C, LIGHT, TDE);
else if (s.dusk > F_NO_PHENOM)
d.writeln(TD_C, NO_PHENOM, TDE);
else if (s.dusk > 24) // next day
d.writeln(TD_C, (s.dusk - 24).toDMS() + "+", TDE);
else
d.writeln(TD_C, s.dusk.toDMS(), TDE);
// length of day
if (Math.abs(s.day) < F_CIRCUMPOLAR)
d.write(TD, (s.day).toDMS(), SP, TDE);
else
d.writeln(TD_C, NO_PHENOM, TDE);
// rise/set azimuths
if (Math.abs(s.rise) > F_NO_PHENOM)
d.writeln(TD_C, NO_PHENOM, TDE);
else
d.writeln(TD, Math.round(s.az_rise), TDE);
if (Math.abs(s.set) > F_NO_PHENOM)
d.writeln(TD_C, NO_PHENOM, TDE);
else
d.writeln(TD, Math.round(s.az_set), TDE);
// maximum altitude
if (s.maxalt < 0)
d.writeln(TD, MINUS + Math.rnd(-s.maxalt, 1), SP, TDE);
else if (s.maxalt < 10)
d.writeln(TD, Math.rnd(s.maxalt, 1), SP, TDE);
else
d.writeln(TD, Math.round(s.maxalt), SP, TDE);
d.writeln(TRE);
}
function showprop(object)
{
var properties = "Properties:\n";
for (var propname in object)
properties += propname + ": " + object[propname] + "\n";
alert(properties);
}