PA0SNY 

Satellites and their tracking data

The purpose of this page is to get familiar with satellite tracking programs.

Tracking of satellites can be done in various ways: one can just wait until a satellites is visible,
or one can listen on frequencies that the satellite's beacon uses. It is better to know when a
satellites is visible/audible.
Fortunately there are various ways to be aware of satellite's positions
and this page gives you
some info on how, why, where. 
There are very many people that find
their hobby with satellites: Weather satellites (providing
pictures), Amateur satellites (providing
radio and data communication), and of course the
International Space Station. This can easily
(well......) be viewed from Earth, and in addition
it provides for (HAM) data communication.


To know the position of satellites, you need a program that shows you the satellite's position
relative to the Earth's surface, and you need acurate kepler data for those programs.
Kepler data, named after the German Astronomer Johannes Kepler who really understood
the tracks of planets, are data that form the unique information of all variables of a satellite track.
Feeding these data into a satellite tracking program, provides you the location of that satellite
relative to the earth at any given moment in past, present or future. Because satellite tracks
vary over time, frequent upgrades are necessary. I try to stick to weekly updates.

Over the years I ran into a number of such tracking programs. In 2004 I found two perfecrt
program with semi-automatic kepler data updates.  You will find more about such programs
when you scroll down on this page.


Now some practical issues

When you have a tracking program, you need kepler data upgrading. Satellites will
show variations of their tracks for various reasons, so frequent update is a must!

In the past I used kepler data from  the AMSAT.ORG organization. Each week I received
two files, the 2-line NASA file and the (less compact) amsat.org file. Since it is very easy
to use the 'net' for automatic and easy kepler file upgrade, I decided in October 2005 to
stop the provisioning of those kepler files. Call it 'progressive vision......'

On my websiteit you can see when ISS can be viewed from (roughly) The Netherlands, and
exactly for The Beautiful Village of Vijfhuizen. Check the startpage for that, by clicking on the
ISS symbols. There is one for my hometown, but also for my 'remote' address in Toulouse...


Here you find my favourite sat tracking programs (descriptions further down!):

A website that provides you with actual visibility data is Heavens Above. Based on your lat/lon,
detailed info is given on visible satellites, as well as for "Iridium flares": sunlight reflected by the
solar panels of Iridium satellites gives (very locally!) a sudden flare, sometimes with a magnitude
of -6 or -7.

To know if ISS (The International Space Station) is visible to us humble earthlings you need to
view the following file:  ISS overflight.  For you to compare: I have added an output of Orbitron
that gives a 3-line listing, but with local Dutch time. This file is self explainatory

To learn about  HOW to watch and HOW to interpret the data in this file, I prepared a separate
page to explain about visibility of ISS, click here


And now: WXtrack and Orbitron . Two satellite tracking programs with great views
and easy controls. It is downloadable freeware.
David Taylor and Sebastian Stoff are
the 'providers'


When I was investigating if and how my own website would pop-up under Google, I encountered
the site of David and Cecile Taylor, and the program WXtrack.
Whenever you want to understand and visualise satellite tracks, check on the two FREE programs
WXtrack and WXtrackGL. Kepler file loading is easy, because the program takes care of it's own
upgrade by clicking one button. At start-up it encourages you to update the kepler data as well. 
Please see my comments on WXtrack and WXtrackGL below.

Because the satellite tracking will always attrack my attention, I recently bumped into another great,
well develloped program. Similarity with WXtrack, but with some 'specials' that make it another
favourite for me: Orbitron of Sebastion Stoff



PA0SNY's view on these sat tracking programs:

WXtrack and WXtrackGL.
Two programs that make it very easy for you to understand the tracks of satellites around the Earth.
For learning purposes this is a great help, if only for the way it is presented to you.  Also for people
with low budget (and low speed internet access) this is a really great way to start with satellite tracking.
The main program WXtrack is only 650 kB and WXtrackGL is just over 300 kB (zipped). Allthough
you get a good basic 'Earth' projection already, it is easy to drag in other maps, with greater details.
This requires a faster computer (I use a Pentium III and that goes fine), especially when that UserMap
file is around 3MB.
I noticed that WXtrackGL uses the same satellite data as  WXtrack, so the programs must be
interlinked in one way or another.
You can register WXtrack, and that gives extra possibilities, mainly for the people that require steering
of antenna rotors (for receiving the weather satellite signals).
What is really impressive of WXtrackGL is the presentation of all satellites in reference to the Earth:
It enables you to zoom in and out and shows the track of one satellite.
The "Geostationnary Satellites Belt" is impressive, just like the GPS (2x per 24hours) satellite skin!
Do yourselves a favour, and check on David and Cecile Taylor's website,
Great show!

Orbitron.
This is a similar program as WXtrack, but it has a different features. It has  a very intuitive approach.
It was develloped by the Polish guy Sebastian Stoff.  I suggest that you take a personal look yourselve:
Sebastian's site
This program of Sebastian gives a great output of various files. These can be screenshots, but also
direct info on satellite visibility. Orbitron can generate these files with three lines: Start of visibility,
maximum elevation, end of visibility. This is an improvement over the WXtrack presentation.
In addition Orbitron can generate a pictorial display of the sky of the chosen location, sort of 'radar'.
This gives direct clues about location of the tracked satellite (azimuth and elevation)
Orbitron is CARDWARE: if you like the (free) programme, Sebastiaan likes to receive a card.
I sent him one!


LogSat.
I list this as this is the program that I used in the past. It shows a clear view of the world, with sats
projected in a clear track. The program also incorporates a logging program for HAM's QSO's.
However......... a problem with the program arose, when Y2K came along, and a special patch was
needed to repair the program. So far (I checked in Oct 2005) the makers have not made any visible
attempt to create a direct  Y2K compliant program. Poor show.
And insulting to the buyer, because this program is not free- nor shareware.  Nor cheap for what you get
Don't bother, see above for the two better programs!
ADVICE: DON'T USE IT. WASTE OF TIME AND MONEY.


page last update September 24, 2006

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