Earth Satellites 

Data from GPS, Glonass, Galileo, Beidou, Stations (includes the International Space Station, ISS), and Iridium satellites are plotted and listed. Other types of satellites may be added in future releases.

  1. A current version the satellite TLE files (Two Line Element) is required first, and this is done from the Tools -> Download Earth Satellite TLE's.
  2. The TLE data in these files will go stale after several weeks (or days), so it is good practice to download a refreshed version of these files at regular intervals. When SkyView is started, it gives a summary of the age of the TLE data that is currently in use.
  3. Select the checkbox for the satellite types that you wish to show. GPS satellite will be shown in blue. Glonass satellites are in red. Stations are Aqua. Iridium are green.
  4. Trails before and after the satellite can be shown by checking the "Show Trails" box, and selecting the time duration. Note selecting trails will increase the computation load.
  5. A tabular list is also shown. The colored background depict when a satellite is above the observer’s horizon while the others are below the observers horizon (the Elevation angle is negative when below the horizon). Azimuth and Elevation are in degrees. The Range column is the distance in kilometres from the observer to a satellite.
  6. If you click on a Satellite in the listing, a black circle will be shown around it on the Satellite plot.
  7. Since the ISS is in a Low Earth Orbit, It will only be above the horizon for about 5 minutes, several times a day from any one location on the earth’s surface, so it is difficult to catch. Although it can pass overhead at any time of the day, it will only be visible either just before sunrise or just after sunset. If the "Find ISS" task is active, then the time of this plot will be same as the ISS pass.

GPS locator  


Finding the International Space Station (ISS)

Clicking on the "Find ISS" button in the top menu brings up a window showing the future passes of the ISS over the current Observer Location.

Before this computation can proceed, a recent copy of the ISS Two Line Elements (TLE) is required. This can be downloaded from Tools -> Download Earth Satellite TLE in the Main Menu. If this file doesn't exist, or is not within 30 days of the current date, then a warning message is given. Since the downloaded TLE file will only correspond current date of download, then this process cannot be used to locate historical passes, or predict passes far into the future. These TLE files quickly become stale (in-accurate), so a fresh TLE file need to be downloaded on a regular basis.

By clicking on a predicted ISS pass, the the trail of the ISS is displayed on the SkyMap as a pink/brown trail. When a part of the the ISS trail is illuminated by the sun, and the sun is below the horizon, the trail is shown in bold font and illuminated part of the trail is in bold pink.