Open Directory - Science: Astronomy: Calendars and Timekeeping
See also: This category in other languages: - The calendar has many options with a standard monthly interface, including sunrise, sunset, and Moon phases. - A proposal for a non-sectarian, culturally neutral calendar system. - The worldwide interactive online astronomical/space calendar and calculator - for friends of astronomy, as well as astronomers. - Extensive descriptions of many timing systems, with information on time zones and Julian day numbers. - Features different views of the night sky, constellations, stars, planets, and other celestial wonders. - Applets related to calendars and keeping time, including sidererial time. - Second full moon in a month, or third full moon in a single season. - Britannica.com explores the history of timekeeping, from sundials to cesium atomic clocks. - 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. - History and FAQs of calendars, from ancient Rome to outer space. Including Julian, Gregorian, Jewish, Islamic, Chinese, and Mayan. - The encyclopaedia of calendars. - Published by Cambridge University Press. Gives a unified algorithmic presentation of the Gregorian, ISO, Julian, Coptic, Ethiopic, and Islamic civil calendars. - Complete guide to times in every time zone in the world. - Explains the cosmological and astronomical influences in creating the Indian calendar. - A list of many American Indian tribe's names for months, days, and other calendar related information. - An explanation of the Julian day number system used by astronomers and calendricists. - Civil time is occasionally adjusted by one second increments. A detailed explanation of what a second actually is, and why leap seconds are necessary. - 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. - 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. - Explains the difference between millennium and year 2000 as the absence of a year zero. - A productivity toolkit for global users and businesses that includes world clock and calendar. - An explanation of the calendar including the origin of the day, week, month and year. - The mathematics and rule explanation for the calendar. - Questions and answers to satisfy the hearts of true millennium buffs. - The mathematics of the calendar in Singapore. - Explanations of the Julian Calendar, the Gregorian Reform, the adoption of the Gregorian Calendar, the length of the tropical year and related matters. - Information such as yearly and monthly calendars, counters, countdown, and the world clock which shows the current time in cities all over the world. - An explanation of lunar, solar, lunisolar, rule-based and other calendars. - Information on the origin of the week, and etymology of month and weekday names.
