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.
The word sidereal derives from the Latin word for âstarâ. This is because sidereal motion is motion with respect to the stars. One sidereal day is the time it takes for a star in the sky to come back to the same place in the sky.Because, for all intents and purposes, the sky is âfixedâ, a sidereal day is when the earth rotates 360Â°. A sidereal day is 23 hours 56 minutes and 4.09 seconds long.A sidereal year is the time it takes for the sun to return to the same position with respect to the stars. Due to the precession of the equinoxes the sidereal year is about 20 minutes longer than the tropical year. sidereal day is 23 hours 56 minutes and 4.09 seconds long. A sidereal year is the time it takes for the sun to return to the same position with respect to the stars.