Convert Draconic Months to Sidereal Days
Convert Draconic Months (drac.mo) to Sidereal Days (sid.d) instantly and accurately.
Conversion Formula
sid.d = drac.mo × 27.2867246
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 Days
A sidereal day = Earth's rotation period relative to the stars = 23 h 56 min 4.0905 s = 86,164.0905 s - ~3 min 56 s shorter than the 24 h solar day because Earth advances ~1° in its orbit each day. Equatorial telescope mounts rotate at one turn per sidereal day to track stars. VLBI, GPS orbit determination, and polar-motion monitoring use sidereal rotation as their reference. 1 sid. day = 86,164.0905 s.
Quick Reference Table
| Draconic Months (drac.mo) | Sidereal Days (sid.d) |
|---|---|
| 1 drac.mo | 27.2867 sid.d |
| 2 drac.mo | 54.5734 sid.d |
| 5 drac.mo | 136.434 sid.d |
| 10 drac.mo | 272.867 sid.d |
| 25 drac.mo | 682.168 sid.d |
| 50 drac.mo | 1364.34 sid.d |
| 100 drac.mo | 2728.67 sid.d |