See also:

• Kids and Teens: School Time: Science: Astronomy and Space: Time  (23)
• Reference: Time  (84)
• Science: Astronomy: Amateur: Sky Calendars  (13)
• Science: Reference: Standards: Individual Standards: ISO: ISO 8601  (50)
• Science: Technology: Metrology  (97)
• Society: Holidays: Calendars and Lists  (23)

ACalendar.com  www.acalendar.com The calendar has many options with a standard monthly interface, including sunrise, sunset, and Moon phases.

Annus Novus Decimal Calendar  www.atlantium.org/calendaran.html A proposal for a non-sectarian, culturally neutral calendar system.

Astro Portal - CalSKY  www.calsky.com The worldwide interactive online astronomical/space calendar and calculator - for friends of astronomy, as well as astronomers.

Astronomical Time Keeping  www.maa.mhn.de/Scholar/times.html Extensive descriptions of many timing systems, with information on time zones and Julian day numbers.

Astronomy and Space Calendar  www.newarkmuseum.org/PermanentCollection/PermanentPlanetariumCollectio… Features different views of the night sky, constellations, stars, planets, and other celestial wonders.

Astronomy by JavaScript: Sun Calculators and More  www.jgiesen.de/astro/astroJS Applets related to calendars and keeping time, including sidererial time.

Blue Moon Myths  www.infoplease.com/spot/bluemoon1.html Second full moon in a month, or third full moon in a single season.

Britannica.com - Clockworks: From Sundials to the Atomic Second  www.britannica.com/clockworks Britannica.com explores the history of timekeeping, from sundials to cesium atomic clocks.

The Calendar, Leap Years and the Year 2000  chemistry.csudh.edu/oliver/smt310-handouts/calendar.htm An explanation of the calendar including the origin of the day, week, month and year.

Calendar Studies  www.hermetic.ch/cal_stud.htm 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  webexhibits.org/calendars History and FAQs of calendars, from ancient Rome to outer space. Including Julian, Gregorian, Jewish, Islamic, Chinese, and Mayan.

Calendopaedia  calendopedia.com The encyclopaedia of calendars.

Calendrical Calculations  emr.cs.uiuc.edu/home/reingold/calendar-book/index.shtml Published by Cambridge University Press. Gives a unified algorithmic presentation of the Gregorian, ISO, Julian, Coptic, Ethiopic, and Islamic civil calendars.

The Chinese Calendar  www.math.nus.edu.sg/aslaksen/calendar/chinese.shtml The mathematics and rule explanation for the calendar.

The Difference Between the Millennium and Year 2000  www.timeanddate.com/counters/mil2000.html Questions and answers to satisfy the hearts of true millennium buffs.

GMT: Greenwich Mean Time  wwp.greenwichmeantime.com Complete guide to times in every time zone in the world.

Hindu Calendar Dates 52nd Century  senthilarumugam.tripod.com/id10.html Explains the cosmological and astronomical influences in creating the Indian calendar.

Indian Moons  www.americanindian.net/moons.html A list of many American Indian tribe's names for months, days, and other calendar related information.

The Islamic Calendar  www.math.nus.edu.sg/aslaksen/calendar/islamic.shtml The mathematics of the calendar in Singapore.

The Julian and Gregorian Calendars  www.hermetic.ch/cal_stud/cal_art.html Explanations of the Julian Calendar, the Gregorian Reform, the adoption of the Gregorian Calendar, the length of the tropical year and related matters.

Julian Day Numbers  www.hermetic.ch/cal_stud/jdn.htm An explanation of the Julian day number system used by astronomers and calendricists.

Leap Seconds  tycho.usno.navy.mil/leapsec.html Civil time is occasionally adjusted by one second increments. A detailed explanation of what a second actually is, and why leap seconds are necessary.

LunarCal - A Perpetual Chinese Lunar Calendar  www.lunarcal.org 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  www.pburch.net/lunarcal.html 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  mayacalendar.com 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  www.millenniummistake.net Explains the difference between millennium and year 2000 as the absence of a year zero.

PlexGlobe: International Clock and Global Kit  www.plexobject.com/software/plexglobe A productivity toolkit for global users and businesses that includes world clock and calendar.

Time and Date  www.timeanddate.com Information such as yearly and monthly calendars, counters, countdown, and the world clock which shows the current time in cities all over the world.

Types of Calendars  www.hermetic.ch/cal_stud/lunarcal/types.htm An explanation of lunar, solar, lunisolar, rule-based and other calendars.

World Holidays: Weeks and Months  www.gkindia.com/holidays/weekdays.htm Information on the origin of the week, and etymology of month and weekday names.