57 lines
1.8 KiB
JavaScript
57 lines
1.8 KiB
JavaScript
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/*!
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* satellite-js v5.0.0
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* (c) 2013 Shashwat Kandadai and UCSC
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* https://github.com/shashwatak/satellite-js
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* License: MIT
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*/
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"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports["default"] = gstime;
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var _constants = require("../constants");
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var _ext = require("../ext");
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/* -----------------------------------------------------------------------------
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*
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* function gstime
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*
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* this function finds the greenwich sidereal time.
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*
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* author : david vallado 719-573-2600 1 mar 2001
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*
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* inputs description range / units
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* jdut1 - julian date in ut1 days from 4713 bc
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*
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* outputs :
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* gstime - greenwich sidereal time 0 to 2pi rad
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*
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* locals :
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* temp - temporary variable for doubles rad
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* tut1 - julian centuries from the
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* jan 1, 2000 12 h epoch (ut1)
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*
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* coupling :
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* none
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*
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* references :
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* vallado 2004, 191, eq 3-45
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* --------------------------------------------------------------------------- */
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function gstimeInternal(jdut1) {
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var tut1 = (jdut1 - 2451545.0) / 36525.0;
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var temp = -6.2e-6 * tut1 * tut1 * tut1 + 0.093104 * tut1 * tut1 + (876600.0 * 3600 + 8640184.812866) * tut1 + 67310.54841; // # sec
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temp = temp * _constants.deg2rad / 240.0 % _constants.twoPi; // 360/86400 = 1/240, to deg, to rad
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// ------------------------ check quadrants ---------------------
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if (temp < 0.0) {
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temp += _constants.twoPi;
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}
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return temp;
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}
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function gstime() {
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if ((arguments.length <= 0 ? undefined : arguments[0]) instanceof Date || arguments.length > 1) {
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return gstimeInternal(_ext.jday.apply(void 0, arguments));
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}
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return gstimeInternal.apply(void 0, arguments);
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}
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