Convert Anomalistic Months to Sidereal Days
Convert Anomalistic Months (anom.mo) to Sidereal Days (sid.d) instantly and accurately.
Conversion Formula
sid.d = anom.mo × 27.62999291
About Anomalistic Months
The anomalistic month = interval between successive Moon perigees = 27.5546 days = 2,380,713.2 s. Slightly longer than the sidereal month because the Moon's perigee precesses, completing one revolution in ~8.85 years. Governs 'supermoons': a full moon at perigee appears ~14% wider and 30% brighter. Tidal forces at perigee are ~30% stronger than at apogee. 1 anom.mo = 27.5546 d.
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.
Quick Reference Table
| Anomalistic Months (anom.mo) | Sidereal Days (sid.d) |
|---|---|
| 1 anom.mo | 27.63 sid.d |
| 2 anom.mo | 55.26 sid.d |
| 5 anom.mo | 138.15 sid.d |
| 10 anom.mo | 276.3 sid.d |
| 25 anom.mo | 690.75 sid.d |
| 50 anom.mo | 1381.5 sid.d |
| 100 anom.mo | 2763 sid.d |