Calendars and the Sky

Choose a historical or fictional culture which had a reasonably sophisticated way of reckoning time: a calendar. Some possible suggestions: the Julian calendar (of the Romans, named after Julius Caesar); the traditional Chinese calendar; any of the Hindu calendars of India; any of the Buddhist calendars used in Southeast Asia; the Hijra calendar (used by many Muslims); the Hebrew calendar; the Korean calendar; any of the traditional Japanese calendars; the ancient Egyptian calendar; the traditional Ethiopian calendar; the pagan/neopagan Wheel of the Year; the Zoroastrian calendar. If you choose Mayan calendar, be aware that it is somewhat complicated, and there is only speculation as to what the tzolk’in might be used for. Give me that speculation and discuss its astronomical implications.

If you have a background in a particular culture, you may write about your own culture’s calendar (and teach me something I didn’t know!)

Alternatively, you may choose to write about the reckoning of time used in any major work of speculative fiction (science fiction, fantasy), including the concept of “astrological ages”; do they themselves form a very long calendar?
Write a short essay of at least a single-spaced page in 12-point font (or two double-spaced pages) about how your calendar relates to the sky. You should address:

how the calendar you have chosen is connected to the motion of the Sun, the stars, the Moon, and anything else of note. How and how well do they line up with the days, months, years, or whatever else the calendar has. Which motions in the sky are treated as more important, and which are treated as less important?
how your calendar accounts for the fact that the Earth’s rotation, the Earth’s orbit, and the Moon’s orbit don’t synch up well. I described what effects this has in the Gregorian calendar above; tell me about the one you have chosen.
any “intercalary months” or leap-whatevers needed to keep your calendar in sync with the various celestial cycles, why they are needed, and how they work
what celestial events your calendar’s reckoning predicts exactly, and which ones are only approximate (for instance, the winter solstice is sometimes 21 December and sometimes 22 December in the Gregorian calendar, because we consider the daily rotation of the Earth to be more important than the exact moment that the axis of the Earth’s tilt is maximally toward or away from the Sun.
You might also write about:

How are the dates of holidays or religious observances reckoned in your calendar? Are all of them the same? Why or why not? (For instance, Easter moves every year but Christmas doesn’t. Why is this?)
Are there any particularly interesting features of your chosen culture’s traditions, geographical origin, or history that inform the calendar, especially those that connect to the stars?
What are the historical ancestors of your calendar (for instance, the Gregorian calendar draws inspiration from the Julian calendar)?
How has this calendar adapted to the modern world?
How will this be graded?
We will grade you out of ten points. The grading will be done mostly by the TA’s, and perhaps partly by me (Dr. Freeman).

Sample Solution