Convert Sidereal Months to Julian Years
Convert Sidereal Months (sid.mo) to Julian Years (a_J) instantly and accurately.
Conversion Formula
a_J = sid.mo × 0.07480263296
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.
About Julian Years
The Julian year (a_J) = exactly 365.25 days = 31,557,600 s - the IAU standard year for astronomical distances. The light-year is formally 1 ly = c × 1 a_J = 9.461 × 10¹⁵ m (IAU 2012 B2). Julian years differ from Gregorian years by only 648 s (~10.8 min/year); important for high-precision astrometry or calculations spanning centuries. 1 a_J = 365.25 d = 31,557,600 s.
Quick Reference Table
| Sidereal Months (sid.mo) | Julian Years (a_J) |
|---|---|
| 1 sid.mo | 0.0748026 a_J |
| 2 sid.mo | 0.149605 a_J |
| 5 sid.mo | 0.374013 a_J |
| 10 sid.mo | 0.748026 a_J |
| 25 sid.mo | 1.87007 a_J |
| 50 sid.mo | 3.74013 a_J |
| 100 sid.mo | 7.48026 a_J |