Learn more by clicking the Google or Facebook button below. Population Demographics for Tonasket, Washington in 2016 and 2017. Other Counties and Cities in Washington.
Sidereal Period versus Synodic Period. 1  Measuring the motion of the Moon around the Earth relative to the distant stars leads us to what is called the sidereal period. 2  Measuring the motion of the Moon around the Earth relative to the Sun leads us to what is called the synodic (pronounced si-nod-ik) period.
As a planet rotates around its axis, the stars appear to move around a projection of the planet's axis into space. The time required for the stars to move once around their paths is called the sidereal period of rotation, or the rotation period of the planet. While the planet rotates, it is also moving around the Sun.