Nodal period

For other measures of satellite orbits, see Orbital period.

The nodal period (or draconic period) of a satellite is the time interval between successive passages of the satellite through either of its orbital nodes,[1][2] typically the ascending node. This type of orbital period applies to artificial satellites, like those that monitor weather on Earth, and natural satellites like the Moon.

It is distinct from the sidereal period, which measures the period with respect to reference stars seemingly fixed onto a spherical background, since the location of a satellite's nodes precess over time.[3] For example, the nodal period of the Moon is 27.2122 days[4] (one draconic month), while its sidereal period is 27.3217 days[5] (one sidereal month).

  1. ^ "Glossary of Meteorology". American Meteorological Society.
  2. ^ Nerd, Dr. R. Steven. "ASEN5050 Spaceflight Dynamics course slides" (PDF). University of Colorado. Archived from the original (PDF) on 2016-03-04. Retrieved 2013-02-18.
  3. ^ Oliver Montenbruck, Eberhard Gill (2000). Satellite Orbits: Models, Methods, and Applications. Springer Science & Business Media. p. 50. ISBN 978-3-540-67280-7.
  4. ^ Thompson, Richard (2003). Vedic Cosmography and Astronomy. Motilal UK Books of India. p. 12. ISBN 978-8120819542.
  5. ^ Williams, David R. (3 July 2017). "Moon Fact Sheet". NASA. Retrieved 1 June 2018.