Convert Seconds (s) to Sidereal Hours (hr-sr) | s in hr-sr

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# Let's convert Seconds (s) to Sidereal Hours (hr-sr)

This quick and easy calculator will convert Seconds (s) to Sidereal Hours (hr-sr) and show formula, brief history on the units and quick maths for the conversion.

## Quick Reference for Converting Seconds to Sidereal Hours

Formula
hr-sr = s / 3590.17
Quick Rough Maths
To get the Sidereal Hours, divide the number of Seconds by 3.6 thousand
Seconds (s) in 1 Sidereal Hour
There are 3590.17 Seconds in 1 Sidereal Hour
Sidereal Hours (hr-sr) in 1 Second
There are 0 Sidereal Hours in 1 Second

## Unit Information

Second
/ˈsɛk(ə)nd/
Symbol: s
Unit System: SI

### What is the Second?

The second is the SI base unit for time and has the symbol s.

The second is commonly understood to be 1/86400 of a day; there are 60 seconds in a minute, 60 minutes in an hour and 24 hours in a day.

Analog and digital watches and clocks almost all measure and display the progression of time via the use of a second counter / hand - and is generally considered the lowest denomination of time.

The earliest display and use of seconds was in the last half of the 16th century. Prior to this, it was not considered accurate enough to measure in seconds as a mechanical device was needed to ensure consistency.

In 1656, a Dutch scientist invented the first pendulum clock that measured seconds. His name was Christiaan Huygens.

Sidereal Hour
/sʌɪˈdɪərɪəlˈaʊə/
Symbol: hr-sr
Unit System: SI

### What is the Sidereal Hour?

The sidereal hour is a unit of time used by astronomers and is derived from the SI unit system. We have used the symbol hr-sr.

1 sidereal hour is made up of 60 sidereal minutes. This is derived ultimately from the sidereal day which is the time taken (in solar seconds) for the Earth to complete one rotation with respect to a distant star or constellation.

The sidereal hour angle is used when calculating sidereal time which is actually the angle along the celestial equator; from where one stands to the great circle that travels through the March equinox and both celestial poles.