Keplerian Elements

The 7-10 numerical values used to describe the motion of a satellite orbiting the earth. With these numbers, it is possible to predict, (within reason), the position of the satellite at any time. This is possible through the use of Johannes Kepler's laws of planetary motion.

The orbital elements are:

1. Epoch
2. Orbital Inclination
3. Right Ascension of Ascending Node
4. Argument of Perigee
5. Eccentricity
6. Mean Motion
7. Mean Anomaly
8. Drag (optional)
9. Revolution Number at Epoch (additional)
10. Attitude (additional)

There are various ways to express the orbital elements. Three popular formats are:

• NASA/NORAD 2-Line Format
• AMSAT Format
• One-Line "Charlie" Elements Format

Of these the NASA/NORAD 2-Line Format is the most common.

Orbital elements can be obtained from:
http://celestrak.com/NORAD/elements/
General information on visual tracking of satellites can be found at:
http://www.heavens-above.com/
Information on Ham satellites and radio tracking can be found at:
http://www.amsat.org/amsat/intro/faqs.html