Second (Sidereal) to Hour (Sidereal) Converter
Unit Converter
Instant · Precise · Universal
28 units available
6 categories total
How to Convert Second (Sidereal) to Hour (Sidereal)
To convert sidereal seconds to solar seconds: multiply by 0.99727. One solar second ≈ 1.00274 sidereal seconds.
1 sidereal second ≈ 0.99727 solar seconds. 86,400 sidereal seconds = 1 sidereal day.
For example, 1 Second (Sidereal) (s (Sid)) = 0.0002777777902 Hour (Sidereal) (h (Sid)).
Second (Sidereal) to Hour (Sidereal) — Common Values
| Second (Sidereal) (s (Sid)) | Hour (Sidereal) (h (Sid)) |
|---|---|
| 0.1 | 0.00002777777902 |
| 0.5 | 0.0001388888951 |
| 1 | 0.0002777777902 |
| 2 | 0.0005555555803 |
| 5 | 0.001388888951 |
| 10 | 0.002777777902 |
| 25 | 0.006944444754 |
| 50 | 0.01388888951 |
| 100 | 0.02777777902 |
| 500 | 0.1388888951 |
| 1000 | 0.2777777902 |
About Second (Sidereal) (s (Sid))
Definition
The sidereal second is 1/60 of a sidereal minute — approximately 0.99727 solar seconds.
Mathematical Relationship
1 sidereal second ≈ 0.99727 solar seconds. 86,400 sidereal seconds = 1 sidereal day.
Conversion Formula
To convert sidereal seconds to solar seconds: multiply by 0.99727. One solar second ≈ 1.00274 sidereal seconds.
Practical Applications
Telescope tracking motors rotate at sidereal rate (1 revolution per sidereal day) to follow stars across the sky.
Interesting Facts
The difference between sidereal and solar seconds (2.73 ms) seems tiny, but over a day it adds up to the full ~236 s difference.
Common Mistakes
Assuming sidereal seconds equal solar seconds. The ~0.27% difference is critical in precision astronomy.
Educational Tips
Multiply any sidereal time interval by 0.99727 to get the solar equivalent. This ratio stays constant at all time scales.
About Hour (Sidereal) (h (Sid))
Definition
The sidereal hour is 1/24 of a sidereal day — approximately 3,590.17 seconds (59 minutes and 50.17 seconds in solar time).
Mathematical Relationship
1 sidereal hour = 3,590.17 solar seconds ≈ 59 min 50.17 s in solar time. 24 sidereal hours = 1 sidereal day.
Conversion Formula
To convert sidereal hours to solar seconds: multiply by 3,590.17. To solar hours: multiply by 0.99727.
Practical Applications
Right ascension in celestial coordinates is measured in hours (0–24 h of sidereal time), directly using sidereal hours.
Interesting Facts
Right ascension is measured in hours: 1 h of RA = 15° of sky. The entire sky is 24 sidereal hours in rotation.
Common Mistakes
Treating sidereal hours as exactly 60 solar minutes. The ~10-second difference matters for precision tracking.
Educational Tips
If you use a star-tracking telescope, it rotates once per sidereal day (23h 56m). Each sidereal hour, it covers 15° of sky.