Calendars – keeping track of time
Useful Sites
Calendars (University of Sydney Library)
Provides information on the history of calendars, an opportunity to make your own calendar, and links to perpetual, ecclesiastical, historical, and literary calendars. You can also search for world public holidays and festivals.
The measurement of time (National Physics Laboratory, UK)
This site gives the definition of time and time scales (eg, calendars, the Earth's rotation, atomic time, the World time standard). It also answers the questions 'Why do we need accurate time?' and 'What are leap seconds and why do we need them?'
Keeping time (In Depth, 18 December 2008, Australian Broadcasting Corporation)
Looks at historical and proposed ways of measuring time (by Carmelo Amalfi).
How time works (How Stuff Works, USA)
Information about measuring time, time zones and daylight-saving time.
Time keeping (National Maritime Museum, Greenwich, UK)
Covers a number of topics relating to time. Of particular interest are 'Leap years' and 'The calendar'.
Calendars (Astronomy Department, New Mexico State University, USA)
By L.E. Doggett and reprinted from the Explanatory Supplement to the Astronomical Almanac, this article provides a detailed look at the Gregorian, Hebrew, Islamic, Indian, Chinese and Julian calendars.
Page updated February 2009.