mirror of
https://github.com/cosinekitty/astronomy.git
synced 2026-01-02 04:28:31 -05:00
223 lines
9.1 KiB
HTML
223 lines
9.1 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<title>Moon Radar Bounce Calculator</title>
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<meta name="viewport" content="width=device-width,maximum-scale=2">
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<link rel="stylesheet" href="astro_demo.css" />
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</head>
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<body id="main_content_wrap" class="inner">
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<h1>Moon Radar Bounce Calculator</h1>
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<h2>Observer</h2>
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<table cellpadding="5" cellspacing="0" border="1">
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<tr>
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<td>
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<div>Date and Time:</div>
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<div>
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<input type="checkbox" id="AutoTimeCheckBox" onchange="OnToggleAutoTime()">
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<label for="AutoTimeCheckBox">Automatic</label>
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</div>
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</td>
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<td>
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<input type="datetime" id="DateTimeBox" size="30">
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</td>
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</tr>
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<tr>
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<td>Latitude:</td>
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<td><input type="text" id="EditLatitude" pattern="[\-\+]?\d+(\.\d*)?" size="10"></td>
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</tr>
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<tr>
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<td>Longitude:</td>
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<td><input type="text" id="EditLongitude" pattern="[\-\+]?\d+(\.\d*)?" size="10"></td>
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</tr>
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<tr>
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<td>Elevation (m):</td>
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<td><input type="text" id="EditElevation" pattern="[\-\+]?\d+(\.\d*)?" size="10"></td>
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</tr>
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</table>
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<h2>Results</h2>
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<table cellpadding="5" cellspacing="0" id="CalcTable" border="1">
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<tr>
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<th>Variable</th>
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<th>Value</th>
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</tr>
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<tr>
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<td>Moon azimuth</td>
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<td id="Moon_az" class="Numeric"></td>
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</tr>
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<tr>
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<td>Moon altitude</td>
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<td id="Moon_alt" class="Numeric"></td>
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</tr>
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<tr>
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<td>Radar round-trip time</td>
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<td id="Moon_trip" class="Numeric"></td>
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</tr>
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</table>
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<p>
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This is a sample page for the open-source project
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<a href="https://github.com/cosinekitty/astronomy/">Astronomy Engine</a>.
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All of the source code and documentation is available there.
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Also, try using your browser's View Source command to look at how this page works.
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</p>
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</body>
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<script src="astronomy.browser.js"></script>
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<script>
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function OnToggleAutoTime() {
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const checkbox = document.getElementById('AutoTimeCheckBox');
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const editbox = document.getElementById('DateTimeBox');
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if (checkbox.checked) {
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editbox.setAttribute('readonly', true);
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} else {
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editbox.removeAttribute('readonly');
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}
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}
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window.onload = function() {
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const StorageKey = 'AstroDemo.Options';
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var Options;
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function ParseDate(s) {
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return new Date((s || '').replace(' ', 'T')); // Safari doesn't like the space character
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}
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function IsValidNumber(s) {
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return typeof s === 'string' && /^[\-\+]?\d+(\.\d*)?$/.test(s);
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}
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function IsValidDate(s) {
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const d = ParseDate(s);
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return Number.isFinite(d.getTime());
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}
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function LoadOptions() {
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let options;
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try {
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options = JSON.parse(window.localStorage.getItem(StorageKey));
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} catch (e) {
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}
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if (!options) options = {};
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if (!IsValidNumber(options.latitude)) options.latitude = '30';
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if (!IsValidNumber(options.longitude)) options.longitude = '-90';
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if (!IsValidNumber(options.elevation)) options.elevation = '0';
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if (typeof options.automatic !== 'boolean') options.automatic = true;
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if (!IsValidDate(options.date)) options.date = FormatDate(new Date());
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return options;
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}
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function SaveOptions() {
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try {
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window.localStorage.setItem(StorageKey, JSON.stringify(Options));
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} catch (e) {
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}
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}
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function Init() {
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let options = LoadOptions();
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document.getElementById('EditLatitude').value = options.latitude;
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document.getElementById('EditLongitude').value = options.longitude;
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document.getElementById('EditElevation').value = options.elevation;
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document.getElementById('DateTimeBox').value = options.date;
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let checkbox = document.getElementById('AutoTimeCheckBox');
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checkbox.checked = options.automatic;
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OnToggleAutoTime();
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return options;
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}
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function Pad(s, w) {
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s = s.toFixed(0);
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while (s.length < w) {
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s = '0' + s;
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}
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return s;
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}
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function FormatDate(date) {
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var year = Pad(date.getFullYear(), 4);
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var month = Pad(1 + date.getMonth(), 2);
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var day = Pad(date.getDate(), 2);
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var hour = Pad(date.getHours(), 2);
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var minute = Pad(date.getMinutes(), 2);
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var second = Pad(date.getSeconds(), 2);
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return `${year}-${month}-${day} ${hour}:${minute}:${second}`;
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}
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function FormatCoord(x) {
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return x.toFixed(3);
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}
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const MOON_MEAN_RADIUS_KM = 1737.4;
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const MOON_MEAN_RADIUS_AU = MOON_MEAN_RADIUS_KM / Astronomy.KM_PER_AU;
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const C_AUDAY = 173.1446326846693; // speed of light in AU/day
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const C_AUSEC = C_AUDAY / (24 * 3600); // speed of light in AU/sec
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function UpdateScreen() {
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const autotime = document.getElementById('AutoTimeCheckBox').checked;
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const timebox = document.getElementById('DateTimeBox');
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const text_latitude = document.getElementById('EditLatitude').value;
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const text_longitude = document.getElementById('EditLongitude').value;
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const text_elevation = document.getElementById('EditElevation').value;
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let date;
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if (autotime) {
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// Automatically update the date/time every second, using the computer's clock.
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date = new Date();
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timebox.value = FormatDate(date);
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} else {
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// Try to parse a date/time from the user's input.
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date = ParseDate(timebox.value);
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}
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if (!IsValidDate(timebox.value) || !IsValidNumber(text_latitude) || !IsValidNumber(text_longitude) || !IsValidNumber(text_elevation)) {
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// Bail out until user corrects problems in the observer coordinates.
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// Gray out the whole table so the user knows there is something wrong.
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document.getElementById('CalcTable').style.display = 'none';
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} else {
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document.getElementById('CalcTable').style.display = '';
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const latitude = parseFloat(text_latitude);
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const longitude = parseFloat(text_longitude);
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const elevation = parseFloat(text_elevation);
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if (latitude !== Options.latitude || longitude !== Options.longitude || elevation !== Options.elevation || Options.automatic !== autotime) {
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Options = {
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latitude: text_latitude,
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longitude: text_longitude,
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elevation: text_elevation,
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automatic: autotime,
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date: timebox.value
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};
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SaveOptions();
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}
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const observer = new Astronomy.Observer(latitude, longitude, elevation);
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// Calculate a vector from the topocentric observer to the center of the Moon.
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const moon_eqd = Astronomy.Equator(Astronomy.Body.Moon, date, observer, true, false);
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const hor = Astronomy.Horizon(date, observer, moon_eqd.ra, moon_eqd.dec, 'normal');
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document.getElementById('Moon_az').innerText = FormatCoord(hor.azimuth);
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document.getElementById('Moon_alt').innerText = FormatCoord(hor.altitude);
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// Find the distance from the topocentric observer to the Moon's surface.
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const dist_au = moon_eqd.vec.Length() - MOON_MEAN_RADIUS_AU;
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// Calculate the round trip radar pulse time in seconds.
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const round_trip_sec = (2 * dist_au) / C_AUSEC;
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document.getElementById('Moon_trip').innerText = FormatCoord(round_trip_sec);
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}
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setTimeout(UpdateScreen, 1000);
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}
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Options = Init();
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UpdateScreen();
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}
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</script>
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</html>
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