Etymologie, Etimología, Étymologie, Etimologia, Etymology, Etymologi
DK Dänemark, Dinamarca, Danemark, Danimarca, Denmark
Kalender, Calendrier, Calendar

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tondering
Frequently Asked Questions about Calendars
by Claus Tøndering

• As a set of web pages
• As a single text file
• As an Adobe Acrobat (PDF) file

• Copyright and disclaimer
• Introduction
• Changes in version 2.7
• Writing dates and years
• The "mod" operator
• The text in square brackets
• Contents
• 1. What Astronomical Events Form the Basis of Calendars?
• 1.1 What are equinoxes and solstices?
• 2. The Christian Calendar
• 2.1 What is the Julian calendar?
• 2.1.1 What years are leap years?
• 2.1.2 What consequences did the use of the Julian calendar have?
• 2.2 What is the Gregorian calendar?
• 2.2.1 What years are leap years?
• 2.2.2 Isn't there a 4000-year rule?
• 2.2.3 Don't the Greek do it differently?
• 2.2.4 When did country X change from the Julian to the Gregorian calendar?
• 2.3 What day is the leap day?
• 2.4 What is the Solar Cycle?
• 2.5 What is the Dominical Letter?
• 2.6 What day of the week was 2 August 1953?
• 2.7 When can I reuse my 1992 calendar?
• 2.8 What is the Roman calendar?
• 2.8.1 How did the Romans number days?
• 2.9 What is the proleptic calendar?
• 2.10 Has the year always started on 1 January?
• 2.11 Then what about leap years?
• 2.12 What is the origin of the names of the months?
• 2.13 What is Easter?
• 2.13.1 When is Easter? (Short answer)
• 2.13.2 When is Easter? (Long answer)
• 2.13.3 What is the Golden Number?
• 2.13.4 How does one calculate Easter then?
• 2.13.5 What is the Epact?
• 2.13.6 How does one calculate Gregorian Easter then?
• 2.13.7 Isn't there a simpler way to calculate Easter?
• 2.13.8 Isn't there an even simpler way to calculate Easter?
• 2.13.9 Is there a simple relationship between two consecutive Easters?
• 2.13.10 How frequently are the dates for Easter repeated?
• 2.13.11 What about Greek Orthodox Easter?
• 2.13.12 Did the Easter dates change in 2001?
• 2.14 How does one count years?
• 2.14.1 How did Dionysius date Christ's birth?
• 2.14.2 Was Jesus born in the year 0?
• 2.14.3 When did the 3rd millennium start?
• 2.14.4 What do AD, BC, CE, and BCE stand for?
• 2.15 What is the Indiction?
• 2.16 What is the Julian Period?
• 2.16.1 Is there a formula for calculating the Julian day number?
• 2.16.2 What is the modified Julian day number?
• 2.16.3 What is the Lilian day number?
• 2.17 What is the correct way to write dates?
• 3. The Hebrew Calendar
• 3.1 What does a Hebrew year look like?
• 3.2 What years are leap years?
• 3.3 What years are deficient, regular, and complete?
• 3.4 When is New Year's day?
• 3.5 When does a Hebrew day begin?
• 3.6 When does a Hebrew year begin?
• 3.7 When is the new moon?
• 3.8 How does one count years?
• 4. The Islamic Calendar
• 4.1 What does an Islamic year look like?
• 4.2 So you can't print an Islamic calendar in advance?
• 4.3 How does one count years?
• 4.4 When will the Islamic calendar overtake the Gregorian calendar?
• 4.5 Doesn't Saudi Arabia have special rules?
• 5. The Persian Calendar
• 5.1 What does a Persian year look like?
• 5.2 When does the Persian year begin?
• 5.3 How does one count years?
• 5.4 What years are leap years?
• 6. The Week
• 6.1 What is the origin of the 7-day week?
• 6.2 What do the names of the days of the week mean?
• 6.3 What is the system behind the planetary day names?
• 6.4 Has the 7-day week cycle ever been interrupted?
• 6.5 Which day is the day of rest?
• 6.6 What is the first day of the week?
• 6.7 What is the week number?
• 6.8 How can I calculate the week number?
• 6.9 Do weeks of different lengths exist?
• 7. The French Revolutionary Calendar
• 7.1 What does a Republican year look like?
• 7.2 How does one count years?
• 7.3 What years are leap years?
• 7.4 How does one convert a Republican date to a Gregorian one?
• 8. The Maya Calendar
• 8.1 What is the Long Count?
• 8.1.1 When did the Long Count start?
• 8.2 What is the Tzolkin?
• 8.2.1 When did the Tzolkin start?
• 8.3 What is the Haab?
• 8.3.1 When did the Haab start?
• 8.4 Did the Mayas think a year was 365 days?
• 9. The Chinese Calendar
• 9.1 What does the Chinese year look like?
• 9.2 What years are leap years?
• 9.3 How does one count years?
• 9.4 What is the current year in the Chinese calendar?
• 10. Frequently Asked Questions about this FAQ
• 10.1 Why doesn't the FAQ describe calendar X?
• 10.2 Why doesn't the FAQ contain information X?
• 10.3 Why don't you reply to my e-mail?
• 10.4 How do I know that I can trust your information?
• 10.5 Can you recommend any good books about calendars?
• 10.6 Do you know a web site where I can find information about X?
• 11. Date
• About this document ...

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