Difference between revisions of "Darian calendar variants"

Latest revision as of 03:02, 21 January 2009

All variants of the Darian calendar have some common properties derived from the original:

• The Martian year (called mir) is divided into 24 months of approximately equal duration
• Have 7 or 6 days per week, and 27 or 28 days per month
• The year is 668 martian sols long
• One leap day, at the end of the leap year
• It has an accuracy of 7750 years
• Begins the year on the vernal equinox
• Each month begins on the first day of the week, and hence so does each mir. The week at the end of each quarter contains only six days. So, it has cycle of perpetuity of 28 days.

Original Darian calendar

Created by Thomas Gangale, it was first published in a paper in 1986. It was names after the author's son, Darius.

A mir is divided into 24 months, resulting a mean month of 27.8579 sols. It is probably much easier for humans to adjust to a slightly shorter month than to accept one that is nearly twice as long, as in other calendars with 12 months.

In the Darian calendar, common years of 668 sols contain 20 months of 28 sols and four months of 27 sols. The 27-sol months occur at the end of each quarter. In leap years of 669 sols, the last month of the year (which also ends the fourth quarter, of course), instead of containing 27 sols, is a normal length of 28 sols. The leap sol is therefore the last sol of the year, rather than being stuck somewhere in the middle as it is on Earth's Gregorian calendar.

Names of the months come from the names of constellations through which the sun appears to pass as seen from Mars during the course of a year. But there are only 12 such constellations, so two names must be used for each constellation. Thus, the first name is the latin name of the constellation, while he second it's the Sanskrit name.

The fact that a martian month has 28 or 27 days makes it even more easier to implement weeks on Mars than Earth. The Latin names of the days of the week are prescribed as a starting point: Dies Solis, Dies Lunae, Dies Martis, Dies Mercurii, Dies Jovis, Dies Veneris, and Dies Saturni.

By choosing the Martian vernal equinox occurring on 1609 March 11 as the epoch for the Darian calendar, any recorded telescopic observation of Mars can be expressed in a common chronological reference system without negative values.

Areosynchronous Calendar

Created by Shaun Moss.

It is identical in structure with the Darian calendar, but with an alternative system of month and day names.

Months are named after the Rotterdam Monthnaming System, but weeks have the names (in order): Heliosol, Neriosol, Libersol, Terrasol, Venusol, Mercusol, Jovisol. The terms Neriosol and Libersol appear instead of Phobosol and Deimosol, which translated would mean "Fear Day" and "Terror Day". (see also: Renaming of Mars' Moons).

Darian Defrost Calendar

Created by Frans Blok.

Identical as structure to the original Darian calendar, but with month and day names based on the Rotterdam system, to eliminate any cultural bias, thus making it probably the best choice for a calendar.

Leap mirs for Darian calendar variants

• If the mir is odd then it is a leap mir having 669 sols (an odd number). This rule accounts for 5000 leap mirs per 10000.
• If the mir is divisible by 10 then this also is a leap mir (in most cases - see following rules). This rule adds a further 1000 leap mirs per 10000, totalling 6000.
• BUT, if the mir is divisible by 100 then it is not a leap mir. This reduces the number of leap mirs per 10000 by 100, bringing us back to 5900.
• BUT, if the mir is divisible by 500 then it is a leap mir. This accounts for 20 more leap mirs per 10000, bringing us to a total of 5920.

Month names for Darian calendar variants

Day of week names for Darian calendar variants

External links and references

• Martian Time
• The Rotterdam Month and Weekday Naming System