Convert Seconds to Sidereal Months
Convert Seconds (s) to Sidereal Months (sid.mo) instantly and accurately.
Conversion Formula
sid.mo = s × 4.236226261e-7
About Seconds
The second (s) is the SI base unit of time, defined since 1967 as exactly 9,192,631,770 periods of the caesium-133 ground-state hyperfine transition at 0 K. Caesium fountain clocks realise this to ~10⁻¹⁶ (1 s lost per ~300 million years); optical lattice clocks (Sr, Yb) reach ~10⁻¹⁸. The second links to the metre via the defined speed of light c = 299,792,458 m/s exactly. 1 s = 1,000 ms = 1/60 min.
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
| Seconds (s) | Sidereal Months (sid.mo) |
|---|---|
| 1 s | 4.236 × 10-7 sid.mo |
| 2 s | 8.472 × 10-7 sid.mo |
| 5 s | 2.118 × 10-6 sid.mo |
| 10 s | 4.236 × 10-6 sid.mo |
| 25 s | 1.059 × 10-5 sid.mo |
| 50 s | 2.118 × 10-5 sid.mo |
| 100 s | 4.236 × 10-5 sid.mo |