Helios calendar

Time on Earth has little meaning to someone who spends their life on another planet. While Martian calendars and clocks have existed since the 20th century, coordinating calendars for every last rock is untenable. As the years progress, precession, tidal dragging, and other factors adjust the time it takes for a body to rotate and orbit - already responsible for a day of error since Egyptian times. Even relativity causes problems. Compared to a stationary observer outside of the solar gravitational well, a second on Earth is, in actuality, only 0.999999984345 of a second.

The following was devised as a solution, at least in the context of the Solar System. As humanity takes the stars, the Silver Calendar will be refined and implemented, though the Helios Calendar is still fairly accurate on these scales. The Helios Calendar is also sometimes referred to as 'the' Solar Calendar (note capitalization). This use is somewhat frowned upon since it has little in common with the standard idea of a solar calendar.

See the Arean calendar for timekeeping on Mars, and Gregorian calendar for the (slightly) modified Earth calendar.

Mechanics

At its core, the Helios Calendar is a simple calendar, with the only traditionally defined unit being the Solar Month, of exactly 3,600,000 seconds, or a thousand hours even. It has a lot in common with the Julian Date, though the intent is to have a reference completely independent of Earth.

The epoch of the Helios Calendar begins with the legendary June 15th, 763 B.C.E solar eclipse during its maximum at 08:23 UT ('GMT') on the Julian Calendar (Julian Date 1,442,902). According to Roman legend, Remus was conceived during this eclipse, and it is mentioned in an Assyrian tablet known as the Eponym Canon. It is perhaps the most familiar as the eclipse referred to in Amos 8: "And it shall come to pass in that day, saith the Lord GOD, that I will cause the sun to go down at noon, and I will darken the earth in the clear day." (KJV)

Common Usage

A date is typically written as 26,153.410 (January 1st, 2222), or, spoken, "Cycle twenty-six, month one-fifty-three, hour four-ten". A cycle being, obviously, 1,000 months (in Terrestrial time, about 114 years, 30 days, 16 hours and 40 minutes).

Since the basic subunit is the hour, outside of Earth, Luna, and Mars, a day is frequently considered to be 25 hours long, with 40 days to the month. A week is usually considered to be ten days long, referred to as quarters - "first week/quarter, second week/quarter", etc.

While it was not, originally, intended as a social calendar, it has quickly gained acceptance as such, even on Earth, due to communication between planets through satmets requiring a mure universal timescheme.