Convert Anomalistic Months to Sidereal Years
Convert Anomalistic Months (anom.mo) to Sidereal Years (a_sid) instantly and accurately.
Conversion Formula
a_sid = anom.mo × 0.07543893504
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 Years
The sidereal year = Earth's orbital period relative to the stars = 365.25636 days = 31,558,149.8 s - about 20 min 24 s longer than the tropical year. The gap arises from precession of the equinoxes (~50 arcsec/year westward drift), which causes the tropical year to end slightly before the sidereal orbit completes. JPL DE440 ephemerides and J2000.0 epoch are anchored to the sidereal frame. 1 a_sid = 365.25636 d.
Quick Reference Table
| Anomalistic Months (anom.mo) | Sidereal Years (a_sid) |
|---|---|
| 1 anom.mo | 0.0754389 a_sid |
| 2 anom.mo | 0.150878 a_sid |
| 5 anom.mo | 0.377195 a_sid |
| 10 anom.mo | 0.754389 a_sid |
| 25 anom.mo | 1.88597 a_sid |
| 50 anom.mo | 3.77195 a_sid |
| 100 anom.mo | 7.54389 a_sid |