Convert Anomalistic Months to Sidereal Months
Convert Anomalistic Months (anom.mo) to Sidereal Months (sid.mo) instantly and accurately.
Conversion Formula
sid.mo = anom.mo × 1.008523982
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 Months
The sidereal month = Moon's orbital period relative to the fixed stars = 27.3217 days = 2,360,591.6 s - the shortest lunar month. It is ~2.21 days shorter than the synodic month (29.53 d) because Earth advances ~27° along its orbit in the same period; the Moon must travel further to re-align with the Sun. Used in GPS orbit design, tidal modelling, and lunar laser ranging. 1 sid.mo = 27.3217 d.
Quick Reference Table
| Anomalistic Months (anom.mo) | Sidereal Months (sid.mo) |
|---|---|
| 1 anom.mo | 1.00852 sid.mo |
| 2 anom.mo | 2.01705 sid.mo |
| 5 anom.mo | 5.04262 sid.mo |
| 10 anom.mo | 10.0852 sid.mo |
| 25 anom.mo | 25.2131 sid.mo |
| 50 anom.mo | 50.4262 sid.mo |
| 100 anom.mo | 100.852 sid.mo |