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<!DOCTYPE html> <HEAD> <TITLE>FAQ</TITLE> <script src="/js/jquery-1.11.js"></script> <meta name="viewport" content="width=device-width, initial-scale=1" /> <meta content="text/html; charset=UTF-8" http-equiv="content-type"> <link rel="stylesheet" href="/css/style.css" type="text/css"> </HEAD> <BODY> <script type='text/javascript' src="/js/passes.js"></script> <script> var startPass = null; var endPass = null; var timer; var issid = 25544; var lat = 1.289987; var lng = 103.850281; go(); </script>   <script async src="https://www.googletagmanager.com/gtag/js?id=G-QZGWPSKPV5"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-QZGWPSKPV5'); </script> <script type='text/javascript'> googletag.cmd.push(function() { googletag.defineSlot('/31043081/n2yo-header', [728, 90], 'div-gpt-ad-1438712706402-0').addService(googletag.pubads()); googletag.pubads().enableSingleRequest(); googletag.enableServices(); }); </script> <div id="headercontainer" style="overflow: auto; zoom: 1"> <table style="width:100%;font-size:14px"> <tr> <td> <div id="logo"> <a href="/"><img src="/img/n2yologo.png" width="200" height="39" border="0" alt="n2yo.com"/></a> <div class="fb-like" data-href="https://www.facebook.com/n2yodotcom" data-send="false" data-layout="button_count" data-width="100" data-show-faces="false" data-font="tahoma"></div> <g:plusone></g:plusone> </div> <span id = "headermessage" style="background-color:#ffffca;border:1px dashed #cacaba;width:300px;"> Tracking <b><span style="color:#d50000">29946</span></b> objects as of 29-Nov-2024 <br/><a href="/space-station/"> HD Live streaming from Space Station</a> <br/> <script src="/js/satellite-js/dist/satellite.min.js"></script> <link rel="stylesheet" href="/css/odometer-theme-car.css" /> <script src="/js/odometer.js"></script> <style> .odometer { font-size: 16px; } </style> <span id="up"><div id="odometer" class="odometer"></div> objects crossing your sky now</up> <script> var items; if (!( /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) )) { $.get("/inc/all.php", function(data) { items = data.split('\n'); up(); }); setInterval('up()', 5000); } else { document.getElementById("up").style.display='none'; } function up() { var cnt = 0; for(var i=0;i<items.length;i++) { var line = items[i]; if(line[0]=="1") { var satid = parseInt(line.substr(2,5)); var line1 = items[i]; var line2 = items[i+1]; var satrec = satellite.twoline2satrec(line1, line2); var now = new Date(); var positionAndVelocity = satellite.propagate( satrec, now.getUTCFullYear(), now.getUTCMonth() + 1, now.getUTCDate(), now.getUTCHours(), now.getUTCMinutes(), now.getUTCSeconds() ); var positionEci = positionAndVelocity.position, velocityEci = positionAndVelocity.velocity; var gmst = satellite.gstimeFromDate( now.getUTCFullYear(), now.getUTCMonth() + 1, now.getUTCDate(), now.getUTCHours(), now.getUTCMinutes(), now.getUTCSeconds() ); var deg2rad = Math.PI/180; var observerGd = { longitude: 103.850281 * deg2rad, latitude: 1.289987 * deg2rad, height: 0 }; try { var positionEcf = satellite.eciToEcf(positionEci, gmst); } catch (err) { //console.log("Error: " + err); } var lookAngles = satellite.ecfToLookAngles(observerGd, positionEcf); var dopplerFactor = 0; var azimuth = lookAngles.azimuth, elevation = lookAngles.elevation, rangeSat = lookAngles.rangeSat; azimuth1 = azimuth*180/Math.PI; elevation1 = elevation*180/Math.PI; if(elevation1>10) { cnt++; } } } odometer.innerHTML = cnt; } </script> </span> </td> <td valign="top" align="center" width="200">    <b><span id="countdown" style="display:block"></span></b> </td> <td align="right" valign="top"> <form action="/database/#results" method="GET"> <div id="searchbox" align="right"> <br/> <INPUT TYPE="text" NAME="q" ID="srcsat" style="font-size: 14px; background-color: #FFFFFF;width:140px" size="12" value="Find 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<div class="menu-icon"></div> <ul> <li class="no-sub"><a class="top-heading" href="https://www.n2yo.com/">Home</a></li> <li> <span class="top-heading"><a class="top-heading" href="/satellites/?c=most-popular">Most tracked</a></span> <i class="caret"></i> <div class="dropdown"> <div class="dd-inner"> <div class="column"> <A HREF="/satellite/?s=25544">SPACE STATION</A> <A HREF="/satellite/?s=36516">SES 1</A> <A HREF="/satellite/?s=33591">NOAA 19</A> <A HREF="/satellite/?s=29155">GOES 13</A> <A HREF="/satellite/?s=25338">NOAA 15</A> <A HREF="/satellite/?s=28654">NOAA 18</A> <A HREF="/satellite/?s=25994">TERRA</A> <A HREF="/satellite/?s=27424">AQUA</A> <A HREF="/satellite/?s=38771">METOP-B</A> <A HREF="/satellite/?s=37849">SUOMI NPP</A> <A HREF="/satellite/?s=36411">GOES 15</A> <A HREF="/satellite/?s=40967">FOX-1A (AO-85)</A> <A HREF="/satellite/?s=27607">SAUDISAT 1C</A> <A HREF="/satellite/?s=41332">KMS-4</A> <A HREF="/satellite/?s=37820">TIANGONG 1</A> <A HREF="/satellite/?s=40069">METEOR M2</A> <A HREF="/satellite/?s=25657">ASIASAT 3S</A> <A HREF="/satellite/?s=36032">NSS 12</A> <A HREF="/satellite/?s=31135">AGILE</A> <A HREF="/satellite/?s=40147">MEASAT 3B</A> <a href="/satellites/?c=most-popular">MORE...</a> </div> </div> </div> </li> <li> <span class="top-heading"><a class="top-heading" href="/satellites/?c=latest-launches">Just launched</a></span> <i class="caret"></i> <div class="dropdown"> <div class="dd-inner"> <div class="column"> <A HREF="/satellite/?s=99130">ASRTU</A> <A HREF="/satellite/?s=62055">STARLINK-32571</A> <A HREF="/satellite/?s=62054">STARLINK-32408</A> <A HREF="/satellite/?s=62053">STARLINK-32494</A> <A HREF="/satellite/?s=62052">STARLINK-32495</A> <A HREF="/satellite/?s=62051">STARLINK-32496</A> <A HREF="/satellite/?s=62050">STARLINK-32492</A> <A HREF="/satellite/?s=62049">STARLINK-32473</A> <A HREF="/satellite/?s=62048">STARLINK-32599</A> <A HREF="/satellite/?s=62047">STARLINK-32630</A> <A HREF="/satellite/?s=62046">STARLINK-32598</A> <A HREF="/satellite/?s=62045">STARLINK-32618</A> <A HREF="/satellite/?s=62044">STARLINK-32577</A> <A HREF="/satellite/?s=62043">STARLINK-32491</A> <A HREF="/satellite/?s=62042">STARLINK-32509</A> <A HREF="/satellite/?s=62041">STARLINK-32456</A> <A HREF="/satellite/?s=62040">STARLINK-32510</A> <A HREF="/satellite/?s=62039">STARLINK-32480</A> <A HREF="/satellite/?s=62038">STARLINK-32477</A> <A HREF="/satellite/?s=62037">STARLINK-32595</A> <a href="/satellites/?c=latest-launches">MORE...</a> </div> </div> </div> </li> <li> <span class="top-heading">Satellites on orbit</span> <i class="caret"></i> <div class="dropdown"> <div class="dd-inner"> <div class="column"> <h4><a href="/satellites/">CATEGORIES</a></h4> <a href="/satellites/?c=2">Int'l Space Station</a> <a href="/satellites/?c=54">Chinese Space Station</a> <a href="/satellites/?c=1">Brightest</a> <a href="/satellites/?c=52">Starlink</a> <a href="/satellites/?c=20">GPS Operational</a> <a href="/satellites/?c=21">Glonass Operational</a> <a href="/satellites/?c=22">Galileo</a> <a href="/satellites/?c=35">Beidou</a> <a href="/satellites/?c=30">Military</a> <a href="/satellites/?c=15">Iridium</a> <a href="/satellites/?c=17">Globalstar</a> <a href="/satellites/?c=10">Geostationary</a> <a href="/satellites/?c=26">Space & Earth Science</a> <a href="/satellites/?c=3">Weather</a> <a href="/satellites/?c=18">Amateur radio</a> <a href="/satellites/">MORE CATEGORIES...</a> </div> <div class="column"> <h4><a href="/whats-up/whats-up-now.php">WHAT'S UP?</a></h4> <a href="/passes/amateur-radio.php">Amateur radio sat passes</a> <a href="/whats-up/?c=20">GPS satellites</a> <a href="/whats-up/?c=21">Glonass satellites</a> <a href="/whats-up/?c=35">Beidou satellites</a> <a href="/whats-up/?c=22">Galileo satellites</a> <a href="/whats-up/?c=15">Iridium satellites</a> <a href="/whats-up/?c=17">Globalstar satellites</a>  <br/> <h4><a href="/database/">FIND A SATELLITE</a></h4> <a href="/database/"> SEARCH DATABASE</a> <a href="/browse/"> BROWSE BY LAUNCH DATE</a> <a href="/satellites/"> BROWSE BY CATEGORY</a> <a href="/satellites/?c=&t=country"> BROWSE BY COUNTRY</a> </div> <div class="column"> <h4><a href="/satellites?c=&t=country">OWNERS/COUNTRIES</a></h4> <a href="/satellites?c=US&t=country"><img src='/img/org/us.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> UNITED STATES</a> <a href="/satellites?c=CIS&t=country"><img src='/img/org/cis.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> CIS (FORMER USSR)</a> <a href="/satellites?c=PRC&t=country"><img src='/img/org/prc.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> PEOPLE'S REPUBLIC OF CHINA</a> <a href="/satellites?c=JPN&t=country"><img src='/img/org/jpn.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> JAPAN</a> <a href="/satellites?c=ESA&t=country"><img src='/img/org/esa.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> EUROPEAN SPACE AGENCY</a> <a href="/satellites?c=FR&t=country"><img src='/img/org/fr.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> FRANCE</a> <a href="/satellites?c=IND&t=country"><img src='/img/org/ind.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> INDIA</a> <a href="/satellites?c=UK&t=country"><img src='/img/org/uk.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> UNITED KINGDOM</a> <a href="/satellites?c=CA&t=country"><img src='/img/org/ca.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> CANADA</a> <a href="/satellites?c=GER&t=country"><img src='/img/org/ger.gif' border='0' width='20' height='15' style="vertical-align: text-bottom"> GERMANY</a> <a href="/satellites?c=&t=country"> MORE OWNERS/COUNTRIES...</a> </div> </div> </div> </li> <li> <a class="top-heading" href="/info/?a=22">Alerting tools</a> <i class="caret"></i> <div class="dropdown right-aligned"> <div class="dd-inner"> <div class="column"> <h4>ALERTING TOOLS</h4> <a href="/info/?a=43"><img src="/ddmenu/phone.png" border="0" width="16" style="vertical-align: text-bottom"> SPACE STATION PREDICTIONS BY VOICE</a> <a href="/login/iss-notifications/"><img src="/ddmenu/alert.png" border="0" width="16" style="vertical-align: text-bottom"> SPACE STATION NOTIFICATION TOOL </a> <a href="/info/?a=15"><img src="/ddmenu/email.png" border="0" width="16" style="vertical-align: text-bottom"> ALERTS BY EMAIL AND SMS</a> </div> </div> </li> <li> <span class="top-heading">More stuff</span> <i class="caret"></i> <div class="dropdown right-aligned"> <div class="dd-inner"> <div class="column"> <h4>ADDITIONAL INFO</h4> <a href="/space-station" style="color:red"><b>HD LIVE STREAMING FROM ISS</b></a> <a href="/news/read.php?p=0">SATELLITE NEWS</a> <a href="/about/?a=donation">MAKE A DONATION</a> <a href="https://www.facebook.com/n2yodotcom">N2YO.COM ON FACEBOOK</a> <a href="/about/?a=links">EXTERNAL LINKS</a> <a href="/about/?a=faq">FAQ</a> <a href="/about/?a=feedback">CONTACT/FEEDBACK</a> <a href="/about/?a=privacy">PRIVACY POLICY</a> <a href="/about/?a=terms">TERMS OF USE</a> </div> <div class="column"> <h4>USER PREFERENCES</h4> <a href=https://www.n2yo.com/login/edit/>SIGN IN</a> <a href="https://www.n2yo.com/login/edit/">EDIT/CHANGE YOUR LOCATION</a> <br/> <h4>SITE OWNERS</h4> <a href="/widgets/">WIDGETS FOR YOUR PAGE</a> <a href="/api/">API ACCESS</a> <br/>  </div> </div> </div> </li> <li class="no-sub"><a class="top-heading" href=https://www.n2yo.com/login/edit/>Sign in</a></li> </ul> </nav>   <table style="width:100%"> <tr> <td class="hidecell" style="vertical-align:top;width:160px"> <script id="mNCC" language="javascript"> medianet_width = "160"; medianet_height = "600"; medianet_crid = "515138167"; medianet_versionId = "111299"; (function() { var isSSL = 'https:' == document.location.protocol; var mnSrc = (isSSL ? 'https:' : 'http:') + '//contextual.media.net/nmedianet.js?cid=8CUY6IMG3' + (isSSL ? '&https=1' : ''); document.write('<scr' + 'ipt type="text/javascript" id="mNSC" src="' + mnSrc + '"></scr' + 'ipt>'); })(); </script> </td> <td valign="top"> <H1>FAQ</H1> </div> <ul> <li><a href="#forafaster">How is my home position determined?</a> <li><a href="#ajax">Why does the main page never reload? I am watching this satellite for several hours but there was no page reload!</a> <li><a href="#multisat">Can I track more that one satellite at a time?</a> <li><a href="#yesyoucan">Can I see satellites passing across the sky?</a> <li><a href="#whatsup">I want to know which satellites are now over my head</a> <li><a href="#multilocations">Can I have a few locations in my profile I can switch?</a> <li><a href="#timezone">What time zone is used for satellite passes prediction?</a> <li><a href="#alowearth">What is a low Earth orbit?</a> <li><a href="#ahighinclination">What are Polar orbits?</a> <li><a href="#ageosynchronous">What is a geosynchronous orbit?</a> <li><a href="#ageostationary">What is a geostationary orbit?</a> <li><a href="#orbitswith">What are Prograde/Retrograde orbits?</a> <li><a href="#intermediate">What is a Intermediate circular orbit?</a> <li><a href="#n2yo">Where does <b>N2YO</b> come from?</a> </ul> <hr> <a name="forafaster">For a faster determination of your home latitude and longitude your position is detected from your current IP address. The geolocation databases is provided by <A HREF="http://www.ip2location.com/" target="_blank">IP2Location</A>. You will need to login to determine your exact location. <p><center><B>* * *</B></center> <a name="ajax">The main page utilizes AJAX (Asynchronous JavaScript And XML) <p><center><B>* * *</B></center> <a name="yesyoucan">Yes you can but not all of them are visible. There are certain factors that make satellites being brighter of fainter. They shold be above the horizon and in a favorable position (illuminated by Sun while you should be in the dark). The brightness of a satellite is a function of its size, surface reflectivity, how well and from what angle the Sun's light is illuminating the satellite, the satellite's height above the horizon, and the corresponding effects of atmospheric interference. On average, a dozen or so satellites are visible at any given time to an observer using binoculars. <p><center><B>* * *</B></center> <a name="multisat">Currently n2yo.com can track in real time up to 5 satellites on the same map. Just go to any satellite details page to manage your tracking list. <p><center><B>* * *</B></center> <a name="whatsup">You may want to try the "What's up in the sky" feature! You have to login first and select your location. <p><center><B>* * *</B></center> <a name="multilocations">Yes, there is no limit, you can save as many location as you want in your profile. <p><center><B>* * *</B></center> <a name="timezone">The time zone is your local time time zone. Actually is your operating system time zone. Please make sure you have configured correctly your system (your computer). <p><center><B>* * *</B></center> <a name="alowearth">A low Earth orbit (LEO) is an orbit around Earth between the atmosphere and the Van Allen radiation belt, with a low angle of inclination. The boundaries are not firmly defined but are typically around 200 - 1200 km (124 - 726 miles) above the Earth's surface. <p><center><B>* * *</B></center> <a name="ahighinclination">A high inclination orbit (80-100 degrees) will take a satellite over the polar regions so that it covers the whole Earth's surface, as the Earth rotates below it. <p><center><B>* * *</B></center> <a name="ageosynchronous">A geosynchronous orbit is a geocentric orbit that has the same orbital period as the sidereal rotation period of the Earth. It has a semi-major axis of 42,164 km. <p><center><B>* * *</B></center> <a name="ageostationary">A geostationary orbit (abbreviated GEO) is a circular orbit directly above the Earth's equator (0 latitude). Any point on the equator plane revolves about the Earth in the same direction and with the same period as the Earth's rotation. It is a special case of the geosynchronous orbit (abbreviated GSO), and the one which is of most interest to operators of artificial satellites (including communication and television satellites) <p><center><B>* * *</B></center> <a name="orbitswith">Orbits with an inclination less than 90 degrees are "prograde" or "direct" (their groundtracks move in the easterly direction, in the direction of Earth's rotation), while orbits with an inclination greater than 90 degrees are "retrograde" (their groundtracks move in the westerly direction, against the direction of Earth's rotation). <p><center><B>* * *</B></center> <a name="intermediate">Intermediate circular orbit (ICO), also called medium earth orbit (MEO), is used by satellites between the altitudes of low earth orbit (up to 1400 km) and geosynchronous orbit (35,790 km). <p><center><B>* * *</B></center> <a name="n2yo">N2YO is the webmaster's ham radio <B>call sign</B>. Amateur radio, often called ham radio, is a hobby enjoyed by many people throughout the world. An amateur radio operator, ham, or radio amateur uses two-way radio to communicate with other radio amateurs for public service, recreation and self-improvement. </td> </tr> </table> <br/><br/><table id="footer">  <tr> <td align="center"> <A HREF="/about/?a=links">Links</A>  <A HREF="/about/?a=terms">Terms of Use</A>  <A HREF="/about/?a=privacy">Privacy Policy</A>  <A HREF="/about/?a=feedback">Contact Us</A> <br/>Copyright © N2YO.com. 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