Convert Weeks to Sidereal Days

Convert Weeks (wk) to Sidereal Days (sid.d) instantly and accurately.

Conversion Formula

sid.d = wk × 7.019165368

About Weeks

A week (wk) = exactly 7 days = 604,800 s. The 7-day week derives from Babylonian astronomy assigning one of the seven classical celestial bodies to each day - preserved in English (Sun-day, Mon-day, Satur-day) and Romance language day names. It spread globally via Jewish, Christian, and Islamic calendars. ISO 8601 numbers weeks 1-52(53) with Monday as day 1. 365-day years contain 52 weeks + 1 day. 1 wk = 7 d = 604,800 s.

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.

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