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. 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 2,520,000 seconds. It is based (very loosely), on the rough comparison of the Martian month (~2485709 seconds), the Lunar month (~2,551,443 seconds), and the rotation of the Sun (2,192,832 seconds).

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

The last three integral digits (938 in the 42,938th month, for example), are often used in much the same way the last two digits of a year are on Earth.

'Dot' is often considered in much the same way an hour is. At 42,133.416, the specific time of the month would be called 'Dot four-sixteen'. Individually, a dot is .001 of a month, or 2,520 seconds (42 minutes).