-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathSun.js
181 lines (178 loc) · 8.4 KB
/
Sun.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
/*
* Copyright (c) 2012, Chris Acky
* Sundial https://github.com/Kalyse/Sundial
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the <organization> nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Credit and References */
// http://lexikon.astronomie.info/zeitgleichung/ EOT
// http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1989MNRAS.238.1529H&db_key=AST&page_ind=2&plate_select=NO&data_type=GIF&type=SCREEN_GIF&classic=YES
// http://code.google.com/p/eesim/source/browse/trunk/EnergySim/src/sim/_environment.py?spec=svn6&r=6
// http://mathforum.org/library/drmath/view/56478.html
// http://www.jgiesen.de/elevaz/basics/meeus.htm
// http://www.ehow.com/how_8495097_calculate-sunrise-latitude.html
// http://www.jgiesen.de/javascript/Beispiele/TN_Applet/DayNight125d.java
// http://astro.unl.edu/classaction/animations/coordsmotion/daylighthoursexplorer.html
// http://www.neoprogrammics.com/nutations/Nutation_In_Longitude_And_RA.php
(function (factory) {
if (typeof define === 'function' && define.amd ) {
// AMD. Register as module
if(typeof dojo === 'object') {
define(["dojo/_base/declare"], function(declare){
return declare( "my.calc.Sun", null, factory());
});
} else {
define( 'Sundial', null, factory());
}
} else {
Sun = new factory();
}
}(function () {
return {
date : new Date(),
getDate : function(){
return this.date;
},
setDate : function(d){
this.date = d;
return this;
},
getJulianDays: function(){
this._julianDays = Math.floor(( this.date / 86400000) - ( this.date.getTimezoneOffset() / 1440) + 2440587.5);
return this._julianDays;
},
// Calculate the Equation of Time
// The equation of time is the difference between apparent solar time and mean solar time.
// At any given instant, this difference will be the same for every observer on Earth.
getEquationOfTime : function (){
var K = Math.PI/180.0;
var T = (this.getJulianDays() - 2451545.0) / 36525.0;
var eps = this._getObliquity(T); // Calculate the Obliquity (axial tilt of earth)
var RA = this._getRightAscension(T);
var LS = this._getSunsMeanLongitude(T);
var deltaPsi = this._getDeltaPSI(T);
var E = LS - 0.0057183 - RA + deltaPsi*Math.cos(K*eps);
if (E>5) {
E = E - 360.0;
}
E = E*4; // deg. to min
E = Math.round(1000*E)/1000;
return E;
},
getTotalDaylightHoursInYear : function(lat){
// We can just use the current Date Object, and incrementally
// Add 1 Day 365 times...
var totalDaylightHours = 0 ;
for (var d = new Date(this.date.getFullYear(), 0, 1); d <= new Date(this.date.getFullYear(), 11, 30); d.setDate(d.getDate() + 1)) {
this.date = d;
// console.log( this.getDaylightHours(lat) );
totalDaylightHours += this.getDaylightHours(lat);
}
return totalDaylightHours;
},
getDaylightHours : function (lat) {
var K = Math.PI/180.0;
var C, Nenner, C2, dlh;
var T = (this.getJulianDays() - 2451545.0) / 36525.0;
this._getRightAscension(T); // Need to get the Suns Declination
Nenner = Math.cos(K*lat)*Math.cos(K*this._sunDeclination);
C = -Math.sin(K*this._sunDeclination)*Math.sin(K*lat)/Nenner;
C2=C*C;
// console.log( T, C2, C, Nenner, lat, K, Math.cos(K*lat) );
if ((C>-1) && (C<1)) {
dlh=90.0 - Math.atan(C / Math.sqrt(1 - C2)) / K;
dlh=2.0*dlh/15.0;
dlh=Math.round(dlh*100)/100;
}
if (C>1) {
dlh=0.0;
}
if (C<-1) {
dlh=24.0;
}
return dlh;
},
_getRightAscension : function(T) {
var K = Math.PI/180.0;
var L, M, C, lambda, RA, eps, delta, theta;
L = this._getSunsMeanLongitude(T); // Calculate the mean longitude of the Sun
M = 357.52910 + 35999.05030*T - 0.0001559*T*T - 0.00000048*T*T*T; // Mean anomoly of the Sun
M = M % 360;
if (M<0) {
M = M + 360;
}
C = (1.914600 - 0.004817*T - 0.000014*T*T)*Math.sin(K*M);
C = C + (0.019993 - 0.000101*T)*Math.sin(K*2*M);
C = C + 0.000290*Math.sin(K*3*M);
theta = L + C; // get true longitude of the Sun
eps = this._getObliquity(T);
eps = eps + 0.00256*Math.cos(K*(125.04 - 1934.136*T));
lambda = theta - 0.00569 - 0.00478*Math.sin(K*(125.04 - 1934.136*T)); // get apparent longitude of the Sun
RA = Math.atan2(Math.cos(K*eps)*Math.sin(K*lambda), Math.cos(K*lambda));
RA = RA/K;
if (RA<0) {
RA = RA + 360.0;
}
delta = Math.asin(Math.sin(K*eps)*Math.sin(K*lambda));
delta = delta/K;
this._sunDeclination = delta;
return RA;
},
// Calculate the Mean Longitude of the Sun
_getSunsMeanLongitude : function(T){
var L = 280.46645 + 36000.76983*T + 0.0003032*T*T;
L = L % 360;
if (L<0) {
L = L + 360;
}
return L;
},
// Nutation in ecliptical longitude expressed in degrees.
_getDeltaPSI : function(T){
var K = Math.PI/180.0;
var deltaPsi, omega, LS, LM;
LS = this._getSunsMeanLongitude(T);
LM = 218.3165 + 481267.8813*T;
LM = LM % 360;
if (LM<0) {
LM = LM + 360;
}
// Longitude of ascending node of lunar orbit on the ecliptic as measured from the mean equinox of date.
omega = 125.04452 - 1934.136261*T + 0.0020708*T*T + T*T*T/450000;
deltaPsi = -17.2*Math.sin(K*omega) - 1.32*Math.sin(K*2*LS) - 0.23*Math.sin(K*2*LM) + 0.21*Math.sin(K*2*omega);
deltaPsi = deltaPsi/3600.0;
return deltaPsi;
},
// T = Time Factor Time factor in Julian centuries reckoned from J2000.0, corresponding to JD
// Calculate Earths Obliquity Nutation
_getObliquity : function (T) {
var K = Math.PI/180.0;
var LS = this._getSunsMeanLongitude(T);
var LM = 218.3165 + 481267.8813*T;
var eps0 = 23.0 + 26.0/60.0 + 21.448/3600.0 - (46.8150*T + 0.00059*T*T - 0.001813*T*T*T)/3600;
var omega = 125.04452 - 1934.136261*T + 0.0020708*T*T + T*T*T/450000;
var deltaEps = (9.20*Math.cos(K*omega) + 0.57*Math.cos(K*2*LS) + 0.10*Math.cos(K*2*LM) - 0.09*Math.cos(K*2*omega))/3600;
return eps0 + deltaEps;
}
};
}));