The orbital parameters provided by Dundee Satellite
Receiving Station are formatted as 14-element records, one per line. Each
record describes the orbit at a particular moment in time (the *epoch*).

- 1. and 2.
**Day at Epoch**(iyr, epoch) - Epoch day of year in GMT (1 <= epoch day < 367), the date of
the specified orbital elements.
*[Integer, Real]* - 3.
**Number of revolutions**per 24 hours (rev) -
*[Real]* - 4.
**Eccentricity**(ecc) - The shape of the orbit where zero defines a circular orbit and higher
values indicate a more elliptical orbit (0 <= eccentricity < 1 for
Earth orbit).
*[Real]* - 5.
**Argument of perigree**at epoch (arpoch) - The angle in the orbital plane from the ascending node to the point
of perigee in the direction of the satellite's motion. Perigee is the point
in the orbit closest to the Earth's center for an elliptical orbit.
*[Real: degrees]* - 6.
**Inclination**of orbit to equatorial plane (einc) - The angle at which the orbit plane crosses the equatorial plane, measured
counter-clockwise from east.
*[Real: degrees]* - 7.
**Rate of change of argument of perigee**(rargp) -
*[Real: degrees per day]* - 8.
**Right ascension of ascending node**(ascnd) - The angle on the equatorial plane from the vernal equinox eastward
to the orbit ascending node, the point where the satellite crosses the
equator on an ascending pass. The vernal equinox is the ascending node
of the Earth's orbit around the Sun.
*[Real: degrees]* - 9.
**Drag term**for SGP4 orbital model (bstar) - The drag term for SGP4 orbital model, used for calculating decay constants for altitude, eccentricity etc. The bstar term is only available when source was two-line data, otherwise set to 0 for TBUS data.
- 10.
**Orbit number**(norb) - The current revolution number. The value is incremented when a satellite crosses the equator on an ascending pass.
- 11.
**Mean anomaly**at epoch (mnan) - The angle on the orbital plane from the point of perigee to the position
of the satellite in the direction of the satellite's motion.
*[Real: degrees]* - 12.
**Greenwich hour angle**(aries) - Celestial longitude of Greenwich Meridian at epoch time.
*[Real: degrees]* - 13.
**Semimajor Axis**(smjaxs) - Half the size of the major axis of the orbit ellipse.
*[Real: km]* - 14.
**Rate of change of Right Ascension**(rascn) - Celestial longitude of satellite when it crosses the equator on an
ascending (northbound) pass.
*[Real: radians per minute]*

## More information

- Satellite information.
- Glossary - commonly used terms and acronyms.
- Information page.

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