Convert Day (Sidereal) (d (sidereal)) to Second (Sidereal) (s (sidereal)) instantly.
About these units
Day (Sidereal) (d (sidereal))
A sidereal day is the time Earth takes to rotate exactly 360 degrees relative to the distant stars—about 23 hours, 56 minutes, 4 seconds. In contrast, the solar day is slightly longer because Earth advances in its orbit each day and must rotate extra degrees for the Sun to appear in the same position in the sky. Sidereal days are fundamental to astronomy: telescopes use sidereal time to track stars, which appear in the same position in the sky at the same sidereal moment each night. This unit anchors astronomical observation to the cosmos rather than to the Sun.
Second (Sidereal) (s (sidereal))
A sidereal second is 1/60 of a sidereal minute, equal to about 0.99727 solar seconds. While the difference seems small, it accumulates noticeably over long observing sessions. Sidereal seconds ensure that telescope mounts and tracking systems remain synchronized with the rotation of the celestial sphere. The distinction between solar and sidereal seconds underscores the complexity of Earth's rotational dynamics—reminding us that even "one second" depends on which cosmic frame of reference we choose.