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Solar calendar

April 07, 2023

A solar calendar is a calendar whose dates indicate the season or almost equivalently the apparent position of the Sun relative to the stars. The Gregorian calendar, widely accepted as a standard in the world, is an example of a solar calendar. The main other types of calendar are lunar calendar and lunisolar calendar, whose months correspond to cycles of Moon phases. The months of the Gregorian calendar do not correspond to cycles of the Moon phase.

The Egyptians appear to have been the first to develop a solar calendar, using as a fixed point the annual sunrise reappearance of the Dog Star—Sirius, or Sothis—in the eastern sky, which coincided with the annual flooding of the Nile River. They constructed a calendar of 365 days, consisting of 12 months of 30 days each, with 5 days added at the year’s end. The Egyptians’ failure to account for the extra fraction of a day, however, caused their calendar to drift gradually into error.[1]

Examples

The oldest solar calendars include the Julian calendar and the Coptic calendar. They both have a year of 365 days, which is extended to 366 once every four years, without exception, so have a mean year of 365.25 days. As solar calendars became more accurate, they evolved into two types.

Tropical solar calendars

If the position of the Earth in its orbit around the Sun is reckoned with respect to the Equinox, the point at which the orbit crosses the celestial equator, then its dates accurately indicate the seasons, that is, they are synchronized with the declination of the Sun. Such a calendar is called a tropical solar calendar[citation needed].

The duration of the mean calendar year of such a calendar approximates some form of the tropical year, usually either the mean tropical year or the vernal equinox year.

The following are tropical solar calendars:

Every one of these calendars has a year of 365 days, which is occasionally extended by adding an extra day to form a leap year, a method called "intercalation", the inserted day being "intercalary".

The Baháʼí calendar, another example of a solar calendar, always begins the year on the vernal equinox and sets its intercalary days so that the following year also begins on the vernal equinox. The moment of the vernal equinox in the northern hemisphere is determined using the location of Tehran "by means of astronomical computations from reliable sources".[2]

Sidereal solar calendars

Further information: Sidereal time

If the position of the Earth (see above) is reckoned with respect to the fixed stars, then the dates indicate the zodiacal constellation near which the Sun can be found. A calendar of this type is called a sidereal solar calendar.[3]

The mean calendar year of such a calendar approximates the sidereal year.

Leaping from one lunation to another, but one Sidereal year is the period between two occurrences of the sun, as measured by the stars' solar calendar, which is derived from the Earth's orbit around the sun every 28 years.[4]

Indian calendars like the Hindu calendar, Tamil calendar, Bengali calendar (non-revised) and Malayalam calendar are sidereal solar calendars. The Thai solar calendar when based on the Hindu solar calendar was also a sidereal calendar. They are calculated on the basis of the apparent motion of the Sun through the twelve zodiacal signs rather than the tropical movement of the Earth.

Non-solar calendars

The Islamic calendar, which is a purely lunar calendar and has a year, whose start drifts through the seasons and so is not a solar calendar. The Maya Tzolkin calendar, which follows a 260-day cycle, has no year, therefore it is not a solar calendar. Also, any calendar synchronized only to the synodic period of Venus would not be solar.

Lunisolar calendars

Lunisolar calendars are lunar calendars that have additional intercalation rules to roughly synchronize the solar year and the seasons. Typical lunisolar calendars have years marked with a whole number of lunar months, so they can not indicate the position of Earth relative to the Sun with the same accuracy as a purely solar calendar.

List of solar calendars

The following is a list of current, historical, and proposed solar calendars:

See also

References

  1. ^ "Solar calendar | chronology | Britannica".
  2. ^ The Universal House of Justice (2014-07-10). "To the Bahá'ís of the World". Retrieved 2014-07-10.
  3. ^ Helen R. Jacobus. (2014). Zodiac Calendars in the Dead Sea Scrolls and Their Reception : Ancient Astronomy and Astrology in Early Judaism. Brill
  4. ^ Leofranc Holford-Strevens. (2005). The History of Time: A Very Short Introduction. OUP Oxford
  5. ^ Denis Feeney. (2007). Caesar's Calendar : Ancient Time and the Beginnings of History. University of California Press

External links

  •   Media related to Solar calendars at Wikimedia Commons
  • Correspondence between Hebrew and Islamic calendars, months and holidays (pdf)

April 07, 2023
solar, calendar, this, article, multiple, issues, please, help, improve, discuss, these, issues, talk, page, learn, when, remove, these, template, messages, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding. This article has multiple issues Please help improve it or discuss these issues on the talk page Learn how and when to remove these template messages This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Solar calendar news newspapers books scholar JSTOR January 2017 Learn how and when to remove this template message This article may be too technical for most readers to understand Please help improve it to make it understandable to non experts without removing the technical details January 2017 Learn how and when to remove this template message Learn how and when to remove this template message A solar calendar is a calendar whose dates indicate the season or almost equivalently the apparent position of the Sun relative to the stars The Gregorian calendar widely accepted as a standard in the world is an example of a solar calendar The main other types of calendar are lunar calendar and lunisolar calendar whose months correspond to cycles of Moon phases The months of the Gregorian calendar do not correspond to cycles of the Moon phase The Egyptians appear to have been the first to develop a solar calendar using as a fixed point the annual sunrise reappearance of the Dog Star Sirius or Sothis in the eastern sky which coincided with the annual flooding of the Nile River They constructed a calendar of 365 days consisting of 12 months of 30 days each with 5 days added at the year s end The Egyptians failure to account for the extra fraction of a day however caused their calendar to drift gradually into error 1 Contents 1 Examples 1 1 Tropical solar calendars 1 2 Sidereal solar calendars 2 Non solar calendars 3 Lunisolar calendars 4 List of solar calendars 5 See also 6 References 7 External linksExamples EditThe oldest solar calendars include the Julian calendar and the Coptic calendar They both have a year of 365 days which is extended to 366 once every four years without exception so have a mean year of 365 25 days As solar calendars became more accurate they evolved into two types Tropical solar calendars Edit This section needs expansion You can help by adding to it January 2017 If the position of the Earth in its orbit around the Sun is reckoned with respect to the Equinox the point at which the orbit crosses the celestial equator then its dates accurately indicate the seasons that is they are synchronized with the declination of the Sun Such a calendar is called a tropical solar calendar citation needed The duration of the mean calendar year of such a calendar approximates some form of the tropical year usually either the mean tropical year or the vernal equinox year The following are tropical solar calendars Ancient Armenian calendar Gregorian calendar Bengali calendar National and official calendar in Bangladesh Iranian calendar Jalali calendar Tabarian calendar Tabarian calendar Indian national calendar Saka calendar Every one of these calendars has a year of 365 days which is occasionally extended by adding an extra day to form a leap year a method called intercalation the inserted day being intercalary The Bahaʼi calendar another example of a solar calendar always begins the year on the vernal equinox and sets its intercalary days so that the following year also begins on the vernal equinox The moment of the vernal equinox in the northern hemisphere is determined using the location of Tehran by means of astronomical computations from reliable sources 2 Sidereal solar calendars Edit Further information Sidereal timeThis section needs expansion You can help by adding to it January 2017 If the position of the Earth see above is reckoned with respect to the fixed stars then the dates indicate the zodiacal constellation near which the Sun can be found A calendar of this type is called a sidereal solar calendar 3 The mean calendar year of such a calendar approximates the sidereal year Leaping from one lunation to another but one Sidereal year is the period between two occurrences of the sun as measured by the stars solar calendar which is derived from the Earth s orbit around the sun every 28 years 4 Indian calendars like the Hindu calendar Tamil calendar Bengali calendar non revised and Malayalam calendar are sidereal solar calendars The Thai solar calendar when based on the Hindu solar calendar was also a sidereal calendar They are calculated on the basis of the apparent motion of the Sun through the twelve zodiacal signs rather than the tropical movement of the Earth Non solar calendars EditThis section needs expansion You can help by adding to it January 2017 The Islamic calendar which is a purely lunar calendar and has a year whose start drifts through the seasons and so is not a solar calendar The Maya Tzolkin calendar which follows a 260 day cycle has no year therefore it is not a solar calendar Also any calendar synchronized only to the synodic period of Venus would not be solar Lunisolar calendars EditThis section needs expansion You can help by adding to it January 2017 Lunisolar calendars are lunar calendars that have additional intercalation rules to roughly synchronize the solar year and the seasons Typical lunisolar calendars have years marked with a whole number of lunar months so they can not indicate the position of Earth relative to the Sun with the same accuracy as a purely solar calendar List of solar calendars EditThe following is a list of current historical and proposed solar calendars Assamese calendar Assyrian calendar Astronomical year numbering Badi calendar Basotho calendar Bengali calendar Berber calendar Bulgar calendar Byzantine calendar Caesar s Calendar 5 Coptic calendar Discordian calendar Era Fascista Ethiopian calendar Florentine calendar French Republican Calendar Gregorian calendar Hanke Henry Permanent Calendar Holocene calendar Indian national calendar International Fixed Calendar Invariable Calendar Jalali calendar Javanese calendar Juche era calendar Julian calendar Malayalam calendar Minguo calendar Nanakshahi calendar Odia calendar Old Icelandic calendar Pancronometer Pataphysical calendar Pax Calendar Pentecontad calendar Pisan calendar Positivist calendar Revised Julian calendar Roman calendar citation needed Runic calendar Solar Hijri calendar Soviet calendar Swedish calendar Symmetry454 Tamil calendar Thai solar calendar Tulu calendar World Calendar World Season CalendarSee also EditList of calendars Lunar calendar Lunisolar calendar Analemma calendar Astronomical clock Daytime astronomy References Edit Solar calendar chronology Britannica The Universal House of Justice 2014 07 10 To the Baha is of the World Retrieved 2014 07 10 Helen R Jacobus 2014 Zodiac Calendars in the Dead Sea Scrolls and Their Reception Ancient Astronomy and Astrology in Early Judaism Brill Leofranc Holford Strevens 2005 The History of Time A Very Short Introduction OUP Oxford Denis Feeney 2007 Caesar s Calendar Ancient Time and the Beginnings of History University of California PressExternal links Edit Media related to Solar calendars at Wikimedia Commons Correspondence between Hebrew and Islamic calendars months and holidays pdf Retrieved from https en wikipedia org w index php title Solar calendar amp oldid 1148082628, wikipedia, wiki, book, books, library,

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