Epoch Date

a continuing count of each day elapsed since January 1^st of the epoch year. The day fraction is just the number of days passed in the particular epoch year. For example, the date above shows "86" as the epoch year (1986) and 50.28438588 as the day fraction meaning a little over 50 days after January 1, 1986.

Inclination - (degrees)

the angle between the equator and the orbit plane

Eccentricity

a constant defining the shape of the orbit (0=circular, Less than 1=elliptical)

Right Ascension of the Ascending Node - (degrees)

the angle between vernal equinox and the point where the orbit crosses the equatorial plane (going north)

Argument of Perigee - (degrees)

the angle between the ascending node and the orbit's point of closest approach to the earth (perigee)

Last Updated June 19, 1997 Contacts