Download Sidereal and Solar Time

Sidereal and Solar Time
 We measure time according to the position of the Sun in the sky.
o Our day is the time from Noon to Noon and is exactly 24 hours long.
 This time period is called a ``Solar Day''.
 It takes the Earth 23 hours 56 minutes and 4 seconds to complete a rotation.
o This time period is called the ``Sidereal Day.''
o During the course of a day the Earth travels a short distance in its orbit
around the Sun.
 After the Earth has completed one rotation the Earth must turn
for an extra 4 minutes in order to bring the Sun back to the same
point in the sky.
 The time from Noon to Noon (the Solar Day) is longer than the
true rotation period of the Earth (Sidereal Day) by about 4
minutes as a result.
 The stars rise and set on a Sidereal schedule.
 A star or constellation will be at precisely the same position in the sky 4
minutes earlier with each successive day.
 The sidereal time at any given location (Celestial Meridian) on earth is the
same as the right ascension at that point.