Sidereal Minute

Sidereal time is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky. A mean sidereal day is about $23 h 56 m 4.1 s$ in length. However, due to variations in the rotation rate of the Earth, the rate of an ideal sidereal clock deviates from any simple multiple of a civil clock. In practice, the difference is kept track of by the difference UTC-UT1, which is measured by radio telescopes and kept on file and available to the public at the IERS and at the United States Naval Observatory. A Sidereal Minute is $1/60^{th}$ of a Sidereal Hour, which is $1/24^{th}$ of a Sidereal Day.