Convert Draconic Months to Sidereal Months
Convert Draconic Months (drac.mo) to Sidereal Months (sid.mo) instantly and accurately.
Conversion Formula
sid.mo = drac.mo × 0.9959943253
About Draconic Months
The draconic (nodical) month = 27.2122 days = 2,351,135.8 s - the interval between successive Moon passages through the same orbital node. Named from the Latin 'draco' (dragon): eclipses only occur near the nodes, where the Moon can align with the Sun or Earth's shadow. The Saros cycle (18 yr 11 d) equals ~242 draconic months, enabling eclipse sequence forecasting. 1 drac.mo = 27.2122 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
| Draconic Months (drac.mo) | Sidereal Months (sid.mo) |
|---|---|
| 1 drac.mo | 0.995994 sid.mo |
| 2 drac.mo | 1.99199 sid.mo |
| 5 drac.mo | 4.97997 sid.mo |
| 10 drac.mo | 9.95994 sid.mo |
| 25 drac.mo | 24.8999 sid.mo |
| 50 drac.mo | 49.7997 sid.mo |
| 100 drac.mo | 99.5994 sid.mo |