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GAIA DR3 2024/02/25 10:59

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Calendar, Artificial satellites

The calculation for artificial satellites uses Mike McCant's QuickSat program and Robert Matson's Iridflar program. Take the time to read the documentation for these programs. It is located in the data/quicksat and data/iridflar folder.

First select the date range for the prediction, the limiting magnitude for the list and to plot to the chart, the TLE file to use for the calculation (use the Ctrl or Shift key to select multiple files). Use the two check boxes on the right if you want to see daytime pass or if you want to include the Iridium flare to the list.

The TLE file for the Iridium flare must be named iridium.tle. If you want to show the satellite path before and after the flare on the chart you must include this file on the list and select a limiting magnitude of at least 8 for the chart.

After clicking Refresh, the list shows the following values:

  • the date and time of maximum elevation
  • the satellite name
  • the maximum magnitude
  • azimuth and altitude of the maxima
  • distance in kilometers
  • right ascension and declination
  • estimated error on the prediction time in minutes or for the flare the distance and direction to the flare maximum, and the direction of the satellite movement.

If the magnitude is between brackets this indicates that the absolute magnitude of the satellite is not known and the calculated value assumes an absolute magnitude of 6. The magnitude file “qs.mag” is updated from along with the tle. You can also replace the file in the User settings\satellite folder manually.

Clicking on the list shows the chart of this satellite pass but also any other object brighter than the limiting magnitude in a time range of +/- 6 minutes.

Please update the TLE element files regularly (at least every week) using the “TLE download” button.
You can select the URL source you want to download from Setup→Internet

The button “Download TLE” download and install the selected files, or if the list is empty, it show you a message with the path where you need to put the files and then open your web browser to the web page.

You can also use a script to download the files. The following example can be used as a starting point to get the files you need. You can get tledownload for Windows or for Linux or Mac. It require you create a space-track account first.

Require software installation

The Quicksat program is a win32 application, it run natively on Windows 32 and 64 bits.
On Linux and Mac you need to install Wine:

Linux Debian/Ubuntu:

sudo apt-get install wine

Linux Fedora:

yum install wine

Mac: See the specific page about Wine installation

The Iridflar program is a dos16 application, it run natively only on Windows 32 bits.
On Windows 64 bits a version of Dosbox is include with the Skychart installer.
On Linux and Mac you need to install Dosbox:

Linux Debian/Ubuntu:

sudo apt-get install dosbox

Linux Fedora:

yum install dosbox

Mac: See just after the Wine installation

en/documentation/artificial_satellites.txt · Last modified: 2023/11/14 12:06 by oldherl