Annosphere Accuracy

Most people can tell you that a year has 365 days. If you want to be fastidious, you can say that a year has 365.25 days, to account for the extra day we add once every four years in the leap year.
 
But that’s not exactly right. The rules governing leap years are complex. In 1923, a calendar adjustment eliminated the extra day for years divisible by 100 that do not leave a remainder of 200 or 600 when divided by 900.

The net result is that according to the revised Julian calendar, a year has 365.24222... days.
 
But even that is not exactly right. From an astronomical perspective, a year has 365.24219 days. By design, a year on the annosphere has 365.24221 days, making it marginally closer than our calendar to the true astronomical length of a year.

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