Convert month to octennial

month

Definition: A month (symbol: mo) is a unit of time used with calendars that approximates the period required for the moon to revolve around Earth. A lunar month lasts approximately 29.53 days, where days are defined based on the SI (International System of Units) base unit of seconds. The Gregorian calendar is the most widely used calendar worldwide, with 365 days (366 in a leap year), 30 or 31 days in each of its 12 months, and 28 or 29 days in February depending on whether or not the year is a leap year.

History/origin: Numerous different calendars have been used throughout history with varying definitions of what constitutes a month. Some of these were lunar calendars based on the monthly cycles of the moon, others were solar calendars that indicated seasons based on the position of the sun relative to the stars, and some were lunisolar calendars that dictated the phase of the moon alongside the time of the solar year. The Gregorian calendar, currently the preferred calendar for civil use, is a reformed version of the Julian calendar which originated from the ancient Roman calendar. It was introduced in 1582 as a reform to the previous Julian calendar which drifted with respect to the equinoxes by 11 minutes per year, which by 1582, resulted in a difference of 10 days from what was expected. In comparison, although the Gregorian calendar is imperfect, it has an error of 1 day in 3,030 years with respect to the current value of the mean solar year, rather than 1 day in 128 years. Though there have since been proposals to further reform the calendar (to make it even more accurate), the Gregorian calendar is deeply ingrained in civil use and shows little sign of changing, barring any new significant discoveries.

Current use: The month is still used in various forms throughout the world. The most common is the use of a month within the Gregorian calendar. Certain cultures, such as that of the Chinese, use a lunisolar calendar in addition to the Gregorian calendar. Chinese New Year for example occurs at a different time each year. Other types of months are also used within astronomy, but the most typically understood form of the month is that of the Gregorian calendar.

octennial

Definition: Octennial is a measure of time duration. For conversion purposes, its value is 252288000 times the reference unit, second.