Search Home : Science : Astronomy : Calendars and Timekeeping
- Annus Novus Decimal Calendar: A proposal for a non-sectarian, culturally neutral calendar system.
- Astro Portal - CalSKY: The worldwide interactive online astronomical/space calendar and calculator - for friends of astronomy, as well as astronomers.
- Astronomical Time Keeping: Extensive descriptions of many astronomical time keeping systems, with information on time zones and Julian day numbers.
- Blue Moon Myths: Second full moon in a month, or third full moon in a single season?
- Britannica.com - Clockworks: From Sundials to the Atomic Second: Britannica.com explores the history of timekeeping, from sundials to cesium atomic clocks.
- Calendar Studies: Articles on the Gregorian and Julian calendars, the ISO date format, the Julian day number system, the Maya calendar, the Goddess lunar calendar, the Liberalia Triday Calendar and C functions for date conversion; plus software for calendrical conversion.
- Calendars through the Ages: History and FAQs of calendars, from ancient Rome to outer space. Including Julian, Gregorian, Jewish, Islamic, Chinese, and Mayan.
- Calendopaedia: The Encyclopaedia of Calendars.
- Calendrical Calculations: Published by Cambridge University Press. Gives a unified algorithmic presentation of the Gregorian, ISO, Julian, Coptic, Ethiopic, and Islamic civil calendars.
- Indian Moons: A list of many American Indian tribe's names for months, days, and other calendar related information.
- Leap Seconds: Civil time is occasionally adjusted by one second increments called leap seconds. A detailed explanation of what a second actually is, and why leap seconds are necessary.
- LunarCal - A Perpetual Chinese Lunar Calendar: LunarCal is a 160-year perpetual Chinese Lunar Calendar for 1900 to 2060. Chinese festivals are listed and the moon phase is displayed.
- Lunisolar Calendar: Lunar calendar with lunations, from new moon to new moon, instead of months. Moon phase on each day. Chinese, Jewish, and Islamic months. Eclipses, meteors, planets, star charts. Christian, Pagan, Islamic, Hindu, and Jewish holidays.
- Maya Calendar 2000: The calendar was the center of Maya life and their greatest cultural achievement. To carry out their astronomical calculations they developed a sophisticated mathematical system. The Maya Calendar website is developing with the intent of providing a complete view of Maya culture.
- Millennium Mistake: Explains the difference between millenium and year 2000 as the absence of a year zero.
- Rosetta Calendar: An online handy tool for converting to and from the Gregorian, Julian and Jewish calendars.
- The Calendar, Leap Years and the Year 2000: An explanation of the calendar including the origin of the day, week, month and year.
- The Chinese Calendar: The mathematics of the Chinese calendar. Explains the rules for the Chinese calendar.
- The Difference Between the Millennium and Year 2000: Questions and answers to satisfy the hearts of true millennium buffs.
- The Islamic Calendar: The mathematics of the Islamic calendar in Singapore.
- Time and Date: Lots of time and date related information, such as yearly and monthly calendars, counters, countdown, and the world clock which shows the current time in cities all over the world.
- Time and Dates: Information on date, time, and time zones from the New York Public Library.
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