Calendar sytem

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Calendar sytem

• By
• Sheela vasantha kumari
• M.TECH (COS)

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Introduction

• A calendar is a system of organizing days for
  social, religious, commercial or administrative
  purposes.
• This is done by giving names to periods of time,
  typically days, weeks, months, and years.
• Periods in a calendar (such as years and months)
  are usually, synchronized with the cycle of the
  sun or the moon.

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CONT.

• Calendars that contain one level of cycles
• week and weekday this system (without year, the
  week number keeps on increasing) is not very
  common year and ordinal date within the year,
  e.g. the ISO 8601 ordinal date system
• Calendars with two levels of cycles
• year, month, and day most systems, including
  the Gregorian calendar (and its very similar
  predecessor, the Julian calendar), the Islamic
  calendar, and the Hebrew calendar year, week, and
  weekday e.g. the ISO week date

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Maya calendar

• The Maya calendar is a system of calendars used
  in pre-Columbian Mesoamerica, and in many modern
  communities in highland Guatemala and in
  Veracruz, Oaxaca and Chiapas, Mexico.
• The Maya calendar consists of several cycles or
  counts of different lengths. The 260-day count is
  known to scholars as the Tzolkin, or Tzolk'in.
• The Tzolkin was combined with a 365-day vague
  solar year known as the Haab' to form a
  synchronized cycle lasting for 52 Haab', called
  the Calendar Round.

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Maya calendar
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Arithmetic and astronomical calendar

• An arithmetic calendar is one that is based on a
  strict set of rules an example is the current
  Jewish calendar. Such a calendar is also referred
  to as a rule-based calendar.
• The advantage of such a calendar is the ease of
  calculating when a particular date occurs. The
  disadvantage is imperfect accuracy. Furthermore,
  even if the calendar is very accurate, its
  accuracy diminishes slowly over time, owing to
  changes in Earth's rotation.

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Gregorian calendar

• Calendars in widespread use today include the
  Gregorian calendar, which is the de facto
  international standard, and is used almost
  everywhere in the world for civil purposes.
• Due to the Gregorian calendar's obvious
  connotations of Western Christianity,
  non-Christians and even some Christians sometimes
  replace the traditional era notations "AD" and
  "BC" ("Anno Domini" and "Before Christ") with
  "CE" and "BCE" ("Common Era" and "Before Common
  Era")..

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Islamic calendar

• The Islamic calendar, Muslim calendar or Hijri
  calendar is a lunar calendar consisting of 12
  lunar months in a year of 354 or 355 days. It is
  used to date events in most of the Muslim
  countries (concurrently with the Gregorian
  calendar), and used by Muslims everywhere to
  determine the proper day on which to celebrate
  Islamic holy days and festivals.
• The first year was the year during which the
  emigration of the Prophet Muhammad from Mecca to
  Medina, known as the Hijra, occurred.With an
  annual drift of 11 or 12 days, the seasonal
  relation is repeated approximately each 33
  Islamic years.

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Islamic Hijri Calendar 1434
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Hindu calendar

• The lunisolar Hindu calendars are some of the
  most ancient calendars of the world. The
  standardized Indian national calendar based on
  Saka era with 78 CE as the start of the calendar
  is a lunar Hindu calendar used by the government
  together with Gregorian calendar. However, it is
  not used by the general public which widely uses
  the Vikrami lunar calendar Vikram Samvat with 56
  BCE as the start of the calendar for religious
  activities and festivals. Vikram Samvat is also
  the official calendar in Nepal. A lunar month may
  have 29 or 30 days. All Hindu calendars have
  about 360 days and they insert an additional 13th
  month (by repeating a month twice in that year)
  every few years to synchronize with solar
  calendar.

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Fiscal calendars

• A fiscal calendar generally means the accounting
  year of a government or a business. It is used
  for budgeting, keeping accounts and taxation. It
  is a set of 12 months that may start at any date
  in a year.
• The US government's fiscal year starts on 1
  October and ends on 30 September. The government
  of India's fiscal year starts on 1 April and ends
  on 31 March.

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Physical calendars

• A calendar is also a physical device (often
  paper) (for example, a desktop calendar or a wall
  calendar). In a paper calendar one or two sheets
  can show a single day, a week, a month, or a
  year. If a sheet is for a single day, it easily
  shows the date and the weekday.
• If a sheet is for multiple days it shows a
  conversion table to convert from weekday to date
  and back. With a special pointing device, or by
  crossing out past days, it may indicate the
  current date and weekday. This is the most common
  usage of the word.

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Bulgar calendar

• The Bulgar calendar was a calendar system used by
  the Bulgars, a seminomadic people, originally
  from Central Asia, who from the 2nd century
  onwards dwelled in the Eurasian steppes north of
  the Caucasus and around the banks of river Volga.
• The main source of information used for its
  reconstruction is a short 15th century transcript
  in Russian language called Nominalia of the
  Bulgarian Khans, which contains 10 pairs of
  calendar terms.

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Religious Calendar

• Religious holidays are determined by a lunisolar
  calendar that is based on calculations of the
  actual postions of the Sun and Moon. Most
  holidays occur on specified lunar dates (tithis),
  a few occur on specified solar dates.
• The calendrical methods presented here are those
  recommended by the Calendar Reform Committee
  (1957). They serve as the basis for the calendar
  published in The Indian Astronomical Ephemeris

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Religious calendar
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Zodiac calendar
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NAMES OF THE WEEKS

• Sunday- sun day
• Monday-moon day
• Tuesday-mars roman god of war
• Wednesday-mercury roman god of peace
• Thursday-Jupiter it is the king of roman god
• Friday-venus roman goodness of love
• Saturday-Saturn day roman god of planting and
  harvest

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• THANK YOU