Instant · Precise · Universal
28 units available
6 categories total
To convert tropical years to days: multiply by 365.24219. To Julian years: multiply by 365.24219/365.25.
1 tropical year ≈ 365.24219 days ≈ 365 d 5 h 48 min 45 s. Shorter than the sidereal year by about 20 minutes due to precession.
For example, 1 Year (Tropical) (yr (Trop)) = 8789.812655 Hour (Sidereal) (h (Sid)).
| Year (Tropical) (yr (Trop)) | Hour (Sidereal) (h (Sid)) |
|---|---|
| 0.1 | 878.9812655 |
| 0.5 | 4394.906328 |
| 1 | 8789.812655 |
| 2 | 17579.62531 |
| 5 | 43949.06328 |
| 10 | 87898.12655 |
| 25 | 219745.3164 |
| 50 | 439490.6328 |
| 100 | 878981.2655 |
| 500 | 4394906.328 |
| 1000 | 8789812.655 |
The tropical year is the time for the Sun to return to the same equinox point — approximately 365.24219 days (31,556,925.216 seconds).
1 tropical year ≈ 365.24219 days ≈ 365 d 5 h 48 min 45 s. Shorter than the sidereal year by about 20 minutes due to precession.
To convert tropical years to days: multiply by 365.24219. To Julian years: multiply by 365.24219/365.25.
Calendar design — the Gregorian calendar's average year (365.2425 days) approximates the tropical year to within 26 seconds.
The tropical year is slowly shortening — by about 0.53 seconds per century. In the year 1900, it was 365.24220 days.
Confusing tropical year with sidereal year — the tropical year is ~20 minutes shorter due to axial precession.
The tropical year governs seasons. If we used the sidereal year for calendars, seasons would slowly drift through the months over ~26,000 years.
The sidereal hour is 1/24 of a sidereal day — approximately 3,590.17 seconds (59 minutes and 50.17 seconds in solar time).
1 sidereal hour = 3,590.17 solar seconds ≈ 59 min 50.17 s in solar time. 24 sidereal hours = 1 sidereal day.
To convert sidereal hours to solar seconds: multiply by 3,590.17. To solar hours: multiply by 0.99727.
Right ascension in celestial coordinates is measured in hours (0–24 h of sidereal time), directly using sidereal hours.
Right ascension is measured in hours: 1 h of RA = 15° of sky. The entire sky is 24 sidereal hours in rotation.
Treating sidereal hours as exactly 60 solar minutes. The ~10-second difference matters for precision tracking.
If you use a star-tracking telescope, it rotates once per sidereal day (23h 56m). Each sidereal hour, it covers 15° of sky.



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