Convert Hours to Sidereal Years
Convert Hours (h) to Sidereal Years (a_sid) instantly and accurately.
Conversion Formula
a_sid = h × 0.0001140751288
About Hours
An hour (h) = exactly 3,600 s. The 24-hour day traces to ancient Egypt (10 daylight hours + 2 twilight + 12 night star-rise periods). Time zones are integer or half-hour UTC offsets (exceptions: India +5:30, Nepal +5:45). The kilowatt-hour = 3,600,000 J; Tc-99m half-life = 6.0067 h. Drug dosing and pharmacokinetics are expressed in hours. 1 h = 3,600 s = 60 min = 1/24 day.
About Sidereal Years
The sidereal year = Earth's orbital period relative to the stars = 365.25636 days = 31,558,149.8 s - about 20 min 24 s longer than the tropical year. The gap arises from precession of the equinoxes (~50 arcsec/year westward drift), which causes the tropical year to end slightly before the sidereal orbit completes. JPL DE440 ephemerides and J2000.0 epoch are anchored to the sidereal frame. 1 a_sid = 365.25636 d.
Quick Reference Table
| Hours (h) | Sidereal Years (a_sid) |
|---|---|
| 1 h | 0.000114075 a_sid |
| 2 h | 0.00022815 a_sid |
| 5 h | 0.000570376 a_sid |
| 10 h | 0.00114075 a_sid |
| 25 h | 0.00285188 a_sid |
| 50 h | 0.00570376 a_sid |
| 100 h | 0.0114075 a_sid |