Professional astronomers rotate the polar axis of their telescopes once every sidereal day (23 hours, 56 minutes, and 4 seconds of clock time), which is the true rotational period of the Earth.
(Professional astronomers; rotate; the polar axis of their telescopes; T:once every sidereal day (23 hours, 56 minutes, and 4 seconds of clock time), which is the true rotational period of the Earth)
Professional astronomers
rotate
the polar axis of their telescopes T:once every sidereal day (23 hours, 56 minutes, and 4 seconds of clock time), which is the true rotational period of the Earth