- Sunrise
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- Sunset
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Traditional
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Ten Exact · your meridian
Your location stays on this device (localStorage). Nothing is sent anywhere.
Star clock
Greenwich —Local —Star-Ten —
Sidereal time follows Earth's spin against the stars (23h 56m 4.09s). It gains about 3m 56s a day on the sun, so it is shown here for reference, not used for Ten.
How Ten works
Ten even hours, starting at sunset
The day starts at sunset, as in the Bible. Ten puts that moment at 0:00:00, which is traditional 6 PM, and that's when the date changes. A day has 10 hours, an hour has 100 minutes and a minute has 100 seconds. That makes 100,000 Ten-seconds a day, each 0.864 ordinary seconds. Midnight is 2:50, 6 AM is 5:00 and noon is 7:50.
Shared and Exact
Shared follows your time zone, so everyone in it reads the same time and can say "call you at 2". Exact is mean solar time on your own line of longitude. It depends only on that longitude, so people due north and due south of you, in either hemisphere, have exactly the same Exact time.
An honest note on the physics
Measured against the stars, Earth turns once every 23h 56m 4.09s (the sidereal day). That's about 4 minutes shorter than the sun day. A clock built on the star day would slip 4 minutes a day against sunset and go a full lap in a year. That's why Ten's hours follow the sun day and the star clock is shown separately. The calendar needs leap days only because a year isn't a whole number of days. A time-of-day clock never needs them.