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: http://sbmg.geol.msu.ru/polinf/calendar.html
Дата изменения: Unknown Дата индексирования: Mon Oct 1 19:52:49 2012 Кодировка: Поисковые слова: moon |
Welcome to Fourmilab's calendar converter! This page allows you to interconvert dates in a variety of calendars, both civil and computer-related. All calculations are done in JavaScript executed in your own browser; complete source code is embedded in this page, and you're free to save the page into a file on your own computer and use it even when not connected to the Internet. To use the page, your browser must support JavaScript and you must not have disabled execution of that language. Let's see...
If the box above says "Your browser supports JavaScript", you're in business; simply enter a date in any of the boxes below and press the "Calculate" button to show that date in all of the other calendars.
The Gregorian calandar is a minor correction to the Julian. In the Julian calendar every fourth year is a leap year in which February has 29, not 28 days, but in the Gregorian, years divisible by 100 are not leap years unless they are also divisible by 400. How prescient was Pope Gregory! Whatever the problems of Y2K, they won't include sloppy programming which assumes every year divisible by 4 is a leap year since 2000, unlike the previous and subsequent years divisible by 100, is a leap year. As in the Julian calendar, days are considered to begin at midnight.
The average length of a year in the Gregorian calendar is 365.2425 days compared to the actual solar tropical year (time from equinox to equinox) of 365.24219878 days, so the calendar accumulates one day of error with respect to the solar year about every 3300 years. As a purely solar calendar, no attempt is made to synchronise the start of months to the phases of the Moon.
A slight modification of the Gregorian calendar would make it even more
precise. If you add the additional rule that years evenly divisible
by 4000 are not leap years, you obtain an average solar year
of 365.24225 days per year which, compared to the actual mean year
of 365.24219878, is equivalent to an error of one day over a period
of about 19,500 years; this is comparable to errors due to tidal
braking of the rotation of the Earth.