Convert Sidereal Days to Anomalistic Months
Convert Sidereal Days (sid.d) to Anomalistic Months (anom.mo) instantly and accurately.
Conversion Formula
anom.mo = sid.d × 0.03619255362
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 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.
Quick Reference Table
| Sidereal Days (sid.d) | Anomalistic Months (anom.mo) |
|---|---|
| 1 sid.d | 0.0361926 anom.mo |
| 2 sid.d | 0.0723851 anom.mo |
| 5 sid.d | 0.180963 anom.mo |
| 10 sid.d | 0.361926 anom.mo |
| 25 sid.d | 0.904814 anom.mo |
| 50 sid.d | 1.80963 anom.mo |
| 100 sid.d | 3.61926 anom.mo |