Convert Sidereal Days to Milliseconds

Convert Sidereal Days (sid.d) to Milliseconds (ms) instantly and accurately.

Conversion Formula

ms = sid.d × 86164090.5

About Sidereal Days

A sidereal day = Earth's rotation period relative to the stars = 23 h 56 min 4.0905 s = 86,164.0905 s - ~3 min 56 s shorter than the 24 h solar day because Earth advances ~1° in its orbit each day. Equatorial telescope mounts rotate at one turn per sidereal day to track stars. VLBI, GPS orbit determination, and polar-motion monitoring use sidereal rotation as their reference. 1 sid. day = 86,164.0905 s.

About Milliseconds

A millisecond (ms) = 10⁻³ s. Human visual reaction time 150-300 ms; auditory reaction 140-160 ms. Echo delays below ~30 ms cause Haas reinforcement; 100-500 ms are perceived as distinct echoes. One cinema frame at 24 fps = 41.7 ms; 60 fps gaming requires 16.7 ms/frame. Millisecond pulsars rotate in 1.4-30 ms. MIDI keyboard on-latency 1-3 ms. 1 ms = 10⁻³ s.

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