Last updated: 4 September 2009

Tracking the International Space Station

From:	rseymour@wolfenet.com (richard seymour)
Visit www.heavens-above.com

here you've got two ways to go (i use both):
(a) tell it where you live and what you want to see, 
and it'll draw star charts of the pass over your site.


Cooler is:
on that pass map's page, in the upper right corner, is a 
link to "orbit".
Click on it.
It'll take you to a page which (scroll down past the path-maps) 
has the numbers you can give to the Autostar so it'll track
the ISS -for- you... . it's fun! it works! (somewhat)

On the Autostar, go to   Object>Satellite>Select[enter]
Now use the scroll keys to see if the ISS is there.
IF it's not, then [mode] back up until you're seeing
Now press scroll-down, and you'll see:
Name: ISS
then feed in the latest numbers you can get (orbits change).
After you've entered the ISS once, future visits to this portion
of the Autostar can use the Edit function (scroll up from "Select").

To track a satellite, press [enter][ when you see its name on the
Select list.  It will calculate the next pass within 6 hours.
When it shows you a "Sat Rises at XX:XX" 
you can scroll down through other pieces of pass information.
When you press [goto], the ETX will swing to where the AOS
(Acquisition of Signal) will occur.
and start counting down the seconds until the expected passage.
Press enter when you see the satellite cross the crosshairs.

The "?" key on the Autostar explains this fairly well.
have fun

Subject:	ISS TLE interpretation
Sent:	Tuesday, March 6, 2001 08:54:46
From:	rseymour@wolfenet.com (richard seymour)
On the Heavens-Above page showing an ISS time, click on the "ISS"
itself... that brings you to a page describing the satellite.  *then*,
on the upper right of -that- page, click on the word "orbit"

(here's the link itself:
http://www.heavens-above.com/orbitdisplay.asp?satid=25544  )

Under the pictures is the two-line element listing.
Below that are the values as a list.

Here are today's values:

1 25544U 98067A   01050.20978583  .00032487  00000-0  36862-3 0  6650
2 25544  51.5750 323.9431 0009808 113.8873  50.0677 15.61998931128644

The 01050.209785   becomes Epoch Year 2001    Epoch Day 50.209785
Move down to the second line.
The 51.5750 is the inclincation,
The 323.9431 is the RA of Asc (or however the Autostar request it)
The (0.)0009808 is the eccentricity. (zero would be a perfect circle)
so you'd key that in as  0.0009808
The remaining numbers on that line are in the order the Autostar wants 

The only "tricky" part is rounding the numbers which won't fit in the
space the Autostar offers, such as Mean Motion: 15.6199893112864 When
you get to the last spot on the Autostar's screen, just round up that
digit if the following digit (which won't fit) is 5 or greater. Such
round-ups may occasionally ripple back up (so 15.619989 might round to

have fun

Go back to the Autostar Information page.

Go back to the ETX Home Page.

Copyright ©2000-1, 2009 Michael L. Weasner / etx@me.com
Submittals Copyright © 2000-1, 2009 by the Submitter
URL = http://www.weasner.com/etx/autostar/as_iss.html