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The Rennali Calendar

The year is 760(24) Genu Rennalio (760 GR).

The Rennali Calendar is a straight Solar calendar based on the length of the vernal year. A normal Rennali year is 468 days. Since this is 0.15606 days longer than the actual vernal year, some years have only 467 days.

The approach to intercalation that the Rennali calendar is very different from the approach of our Julian-descended solar calendar. Though it is a solar calendar, in some ways the Rennali calendar is more like Earth's lunisolar calendars based on the Metonic cycle, such as the Hebrew calendar, or the calendars of Babylon or ancient Athens.

The Rennali calendar follows a basic pattern where short years alternate between being spaced 6 years apart, and being spaced 7 years apart. Specifically in a 32-year cycle the 6th, 13th, 19th, 26th, and 32nd year are short. Then it starts a new 32-year cycle, so counting from the same starting point, the 38th year will be short, then the 45th, etc.

Each year is divided into 13 months of 36 days each. On short years, the 7th month has only 35 days.

Standardly, the years are numbered from a starting point 760 years before the present day. Some people claim it counts from the date of the founding of Tal Katar, or various other historical events, but the exact signifigance is controversial and unproven.

Sometimes the number of the year is followed by the number of the year it is in the current 32-year cycle. So the current year is sometimes written as 760(24) GR meaning that it is 760th Year of Rennali and the 24th year of the current 32-year cycle. Thus the last short year was five years ago in 755(19), and the next will be in 762(26); In nine years it will be the start of a new 32-year cycle, 769(1).

Gnomish Refinements

Largely ignored by most laymen, and many non-gnomish matheticians and astronomers, there is an ongoing debate among gnome astronomers as to how the Rennali calendar should be made more exact. Since the "problem" in question is that the calendar will drift over a scale of hundreds of thousands or millions of years, and the solutions are proposed to be implemented on cycles of 480 years or more, the debate is widely regarded lacking practicality.

In the early 600's GR, a gnomish mathematician named Gianv wrote and distributed a book in which he calculated the length between vernal equinoxes to be 467.84394 days (or rather he calculated it to 32B.A164 in duodecimal), and that the with only the 32 year cycle the vernal equinox would move one day later in the year every 5,184 years. He proposed that an extra 7 years be added to every fifteenth "32"-year cycle, so that it had short days on years 6, 13, 19, 26, 32, and 39, before starting a new, normal cycle in order to solve this problem. He calculated that with this correction the equinox would move only one day later in 2.5 million years.

A decade later, in 624, another gnomish mathematician, Kepr, found an even more precise value for the vernal year, 32B.A163B12. By her new calculations, Gianv's proposed calendar would cause the equinox to move a day earlier every quarter million years, rather than a day later in ten times as long. She proposed instead that after every 20 32-year cycles, an extra, 20-year cycle be added in which the 7th, 13th, and 20th years were short. By her calculations, this would have the equinox moving one day later in the calendar every 2 million years.

Kepr's proposal is still highly regarded by the debators to this day, though there is heated debate over whether an 833-year cycle would be even better.

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