As a consequence of Earth s rotation celestial Earths rotati

As a consequence of Earth s rotation, celestial, Earth\'s rotation, celestial objects such as the moon and the stars appear to move across the sky, rising in the east and setting in the west. As a result, if a telescope on Earth remains stationary while viewing a celestial object, the object will slowly move outside the viewing field of the telescope. For this reason, a motor is often attached to telescopes so that the telescope rotates at the same rate as Earth. Determine how long it should take the motor to turn the telescope through an angle of 1 min in a direction perpendicular to Earth\'s axis.

Solution

Total number of seconds in a day is 24 x 60 x 60 = 86400 seconds

Total number of minutes of arc of a circle = 360 x 60 = 21600 minutes

Hence time taken to rotate for earth to rotate through one minute of arc of a circle = 86400 / 21600 = 4 seconds.