Cool STEM - Observing Man-made Earth Satellites

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Lorenzo von Matterhorn
Jan 31, 2009
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This hobby can cost nothing and is fantastic for imagination expanding STEM. I use the free Heavensat software linked to below, so I don't know how accurate the following tutorial is which refers to the on-line site.

There is at least one free Android tablet satellite tracking apps which uses GPS and other tablet sensors to present a red-line projection on the LCD which can be held against the sky at night to see where a satellite pass should be found. I don't use it, so I don't know how well it works. The guide.:

Some of the brighter satellites in Earth orbit are easy to observe when the weather cooperates. Of course, one
must know when to look for them and where in the sky they will appear. The easiest to use web site to help you
in that respect is Here's how to use that site:

1. Go to With the possible exception of a visit to the site made from a mobile device, the web site
will automatically detect your location, something that must be known to calculate satellite pass data for your

2. In the upper left hand corner of the N2YO home page, you will see a short list of the "Most Tracked"
satellites. Click on "ISS (ZARYA)" which is the link to the International Space Station tracking data. Because the
ISS is by far the brightest satellite in orbit, it is typically at the top of the list. If it isn't, click on "Top 50", then
find and click on "ISS (ZARYA)" within the displayed list.

3. You should now be on the ISS (ZARYA) page. Click on "5 Day predictions", a link that will be near the top of
the page.

4. After a short delay as the satellite passes are calculated, you should see a color version of the table shown on
page 2 of this handout. Just to be sure that only visible passes are listed in the table, after arriving at that
page, click on the "Show visible passes only" button. The meaning of the most important column labels in the
resulting table are as follows:

Start - the local time at which the satellite first becomes visible in the sky. All times given are in 24 hour
format. For the PM time equivalents of the times shown in the table on page 2, subtract 12 from the time
shown. For example, 19:09 is 7:09 PM.

Max Altitude - the maximum angle above the horizon in degrees that the arc of the satellite's path will reach
as it moves through the sky. The higher this number, the better. 90 degrees would be directly overhead.

End - the local time at which the satellite should no longer be visible. Don't get discouraged too soon
and quit looking.

Date, time - the date and time that the satellite will become visible in the sky due to reflected sunlight.

Az - Azimuth, the direction to the point in the sky where the satellite should appear. For example, using the
first ISS pass data found in the table on page 2, WSW means "West Southwest" meaning just slightly south of
due west. The degree figure also given is helpful, 240 degrees in the example. 0 degrees is due north, 90
degrees is due east, 180 degrees is due south, and 270 degrees is due west.

Watch the sky at about a 45 degree angle above the horizon (halfway to directly overhead) at the "Start"
azimuth given. Especially for a bright satellite like the ISS, your peripheral vision should catch the satellite’s
appearance after which you will be able to track it easily by eye.

If you couldn't find the satellite in the sky at its listed start time, watch for the satellite in the specific
area of the sky given in the bold text data below the "Max Altitude" column of the table.

Mag - the visual magnitude (brightness) of the satellite. The more negative the number, the brighter the
satellite will appear in the sky. For example, a pass at magnitude -2.0 will be much brighter than
a pass at magnitude 0.1. Magnitude -2.0 is twice as bright as magnitude -1.0 and magnitude
-1.0 is twice as bright as magnitude 0.0, so the magnitude -2.0 pass will be slightly greater than four times as
bright as the later 0.1 magnitude pass. However, one must also consider the darkness of the sky at the time of
the pass to judge relative brightness against the background sky.

Visual Satellite Observer's Home Page

SeeSat-L Home Page (visual satellite trackers mailing list)

SeeSat-L Mailing List Archives

The news that inspired me to write this post:

No Secrets: Russia to Publish Catalog Disclosing US Military Satellites - 22 Jun 16

The U.S. has been publishing the orbital elements for the milsats of other countries for a very long time, but not for ours. Why? Well, obvously, knowledge of a spysat pass can possibly allow one to avoid being seen by it. For that reason, I never contributed to the tracking efforts of these hobbyists, I just used their products, the spysat orbital elements they produced that allow me to see OUR stuff.

Now, it looks like the Ruskies might finally be publishing our milsat orbital elements which will take much of the fun away for those amateur trackers worldwide who have fun finding, then tracking U.S. military satellites. I'm surprised it took them this long to do this. Perhaps due to some leftover USSR paranoia they didn't want to let us know what they know.

Here's the best visual satellite tracking software by far, Heavensat, and its free from a Russian author:

The Chinese spysats - Yaogan:

China's Yaogan Triplets. 9A,9B,9C. June 30, 2012 (video)


More Yaogan triad videos:

I've attached the Two Line Element Set (tle) file I created for the Yaogan milsats (5 Jun 16). Rename to .tle if required by your satellite tracking program. Heavensat just uses .txt.

Some in the series orbit in formations I prefer to call triads and are used for signal triangulation. They are still using three sats while ours (NOSS) can now get by with two which is far less fun to watch since the triad provides a VERY cool formation perspective change especially on high elevation passes. Unfortunately, our old triads eventually drift out of formation because they are no longer actively station keeping. As always, a dark sky is best and these are just below naked eye visibility. 7x50 binocs are more than adequate.

With NOSS passes, some actually present them as ET UFO formations, probably just to get YouTube view numbers.:

ECETI: Ufo TRIANGLE SHIP 9/1 or NOSS / Triple Iridium flare


Naval Ocean Surveillance System

These very large U.S. synthetic aperture spysats are very bright and often golden in color:

Lacrosse (SAR)

Iridium civilian comm satellite brightness flares are incredibly bright. I've easily seen them through thin clouds in urban lighting conditions!

Iridium flare prediction sites:

This French guy does a lot of cool telescopic video tracking of various objects in Earth orbit:

Iridium flares video:

Spysat videos:

View attachment Yaogan.txt
Cool! Just watched ISS pass overhead. On the tablet at least. Currently cloudy and thunderstorms.

Should be a good addition to my night sky watching.

One page on his web site:
This is the only image ever taken from the ground of an astronaut in extravehicular activity (EVA1). Steve Bowen, attached to the end of the ISS robotic arm (MSS), was working on a defective ammonia pump. The pump was hooked to the ISS mobile base system (MBS). All major elements of the robotic arm are visible, including the structures of the motorized joints and some elements along the arms (smaller than the astronaut).


His gear: