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Jalali Calendar
The Jalali calendar is a solar calendar, was compiled during the reign of Jalaluddin Malik-Shah I of Seljuk by the order of Nizam al-Mulk and the place of observation were the cities of Isfahan (the capital of the Seljuks), Rey, and Nishapur. Variants of the Jalali calendar are still in use today in Iran and Afghanistan. In Iran, the Persian names of the zodiac are used while in Afghanistan the original Arabic names are used. It gains approximately 1 day on the Julian calendar every 128 years. The tropical Jalali calendar ( fa, گاه‌شماری جلالی or تقویم جلالی), which inherited some aspects from the Yazdgerdi calendar, was adopted on 15 March 1079 by the Seljuk Sultan Jalal al-Din Malik Shah I (for whom it was named), based on the recommendations of a committee of astronomers, including Omar Khayyam, at the imperial observatory in his capital city of Isfahan. Month computations were based on solar transits through the zodiac. It remained in use for eight ...
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Solar Calendar
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 type of calendar is a lunar 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. Examples The oldest solar calendars include the Julian calendar a ...
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Omar Khayyam
Ghiyāth al-Dīn Abū al-Fatḥ ʿUmar ibn Ibrāhīm Nīsābūrī (18 May 1048 – 4 December 1131), commonly known as Omar Khayyam ( fa, عمر خیّام), was a polymath, known for his contributions to mathematics, astronomy, philosophy, and Persian poetry. He was born in Nishapur, the initial capital of the Seljuk Empire. As a scholar, he was contemporary with the rule of the Seljuk dynasty around the time of the First Crusade. As a mathematician, he is most notable for his work on the classification and solution of cubic equations, where he provided geometric solutions by the intersection of conics. Khayyam also contributed to the understanding of the parallel axiom.Struik, D. (1958). "Omar Khayyam, mathematician". ''The Mathematics Teacher'', 51(4), 280–285. As an astronomer, he calculated the duration of the solar year with remarkable precision and accuracy, and designed the Jalali calendar, a solar calendar with a very precise 33-year intercalation cycle''The Cam ...
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Calendar Eras
A calendar is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years. A date is the designation of a single and specific day within such a system. A calendar is also a physical record (often paper) of such a system. A calendar can also mean a list of planned events, such as a court calendar or a partly or fully chronological list of documents, such as a calendar of wills. Periods in a calendar (such as years and months) are usually, though not necessarily, synchronized with the cycle of the sun or the moon. The most common type of pre-modern calendar was the lunisolar calendar, a lunar calendar that occasionally adds one intercalary month to remain synchronized with the solar year over the long term. Etymology The term ''calendar'' is taken from , the term for the first day of the month in the Roman calendar, related to the verb 'to call out', referring to the "calling" of the new moon when it was first se ...
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Armenian Calendar
Armenian may refer to: * Something of, from, or related to Armenia, a country in the South Caucasus region of Eurasia * Armenians, the national people of Armenia, or people of Armenian descent ** Armenian Diaspora, Armenian communities across the world * Armenian language, the Indo-European language spoken by the Armenian people ** Armenian alphabet, the alphabetic script used to write Armenian ** Armenian (Unicode block) * Armenian Apostolic Church * Armenian Catholic Church People * Armenyan, or in Western Armenian, an Armenian surname **Haroutune Armenian (born 1942), Lebanon-born Armenian-American academic, physician, doctor of public health (1974), Professor, President of the American University of Armenia **Gohar Armenyan (born 1995), Armenian footballer **Raffi Armenian (born 1942), Armenian-Canadian conductor, pianist, composer, and teacher Others * SS ''Armenian'', a ship torpedoed in 1915 See also * * Armenia (other) * Lists of Armenians This is a list o ...
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Solar Hijri Calendar
The Solar calendar ( fa, گاه‌شماری هجری خورشیدی, Gâhšomâri-ye Xoršidi; ps, لمريز لېږدیز کلیز, lamrez legdez kalhandara; ku, ڕۆژژمێری کۆچیی ھەتاوی, Salnameya Koçberiyê) is a solar calendar and one of the various ancient Iranian calendars. It begins on the March equinox as determined by astronomical calculation for the Iran Standard Time meridian (52.5°E, UTC+03:30) and has years of 365 or 366 days. It is the modern principal calendar of both Iran and Afghanistan, and is sometimes also called the Shamsi calendar, and abbreviated as SH, HS or, by analogy with AH, AHSh. The Ancient Iran Solar calendar is one of the oldest calendars in the world, as well as the most accurate solar calendar in use today. Since the calendar uses astronomical calculation for determining the vernal equinox, it has no intrinsic error. It is older than the Lunar Hijri calendar used by the majority of Muslims (known in the West as the Isla ...
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Iranian Calendars
The Iranian calendars or Iranian chronology ( fa, گاه‌شماری ایرانی, ) are a succession of calendars invented or used for over two millennia in Iran, also known as Persia. One of the longest chronological records in human history, the Iranian calendar has been modified time and again during its history to suit administrative, climatic, and religious purposes. The most influential person in laying the frameworks for the calendar and its precision was the 11th century Persian polymath, hakim Omar Khayyam. The modern Iranian calendar is currently the official civil calendar in Iran and Afghanistan. The Iranian new year begins at the midnight nearest to the instant of the northern spring equinox, as determined by astronomic calculations for the meridian (52.5°E). It is, therefore, an observation-based calendar, unlike the Gregorian, which is rule-based. This equinox occurs on or about 20 March of the Gregorian calendar. The time zone of Iran is Iran Standard Time, ...
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Ephemeris
In astronomy and celestial navigation, an ephemeris (pl. ephemerides; ) is a book with tables that gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky, i.e., the position (and possibly velocity) over time. Historically, positions were given as printed tables of values, given at regular intervals of date and time. The calculation of these tables was one of the first applications of mechanical computers. Modern ephemerides are often provided in electronic form. However, printed ephemerides are still produced, as they are useful when computational devices are not available. The astronomical position calculated from an ephemeris is often given in the spherical polar coordinate system of right ascension and declination, together with the distance from the origin if applicable. Some of the astronomical phenomena of interest to astronomers are eclipses, apparent retrograde motion/planetary stations, planetary es, sidereal tim ...
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Hindu Calendar
The Hindu calendar, Panchanga () or Panjika is one of various lunisolar calendars that are traditionally used in the Indian subcontinent and Southeast Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, but differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start. Of the various regional calendars, the most studied and known Hindu calendars are the Shalivahana Shaka (Based on the King Shalivahana, also the Indian national calendar) found in the Deccan region of Southern India and the Vikram Samvat (Bikrami) found in Nepal and the North and Central regions of India – both of which emphasize the lunar cycle. Their new year starts in spring. In regions such as Tamil Nadu and Kerala, the solar cycle is emphasized and this is calle ...
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Surya Siddhanta
The ''Surya Siddhanta'' (; ) is a Sanskrit treatise in Indian astronomy dated to 505 CE,Menso Folkerts, Craig G. Fraser, Jeremy John Gray, John L. Berggren, Wilbur R. Knorr (2017)Mathematics Encyclopaedia Britannica, Quote: "(...) its Hindu inventors as discoverers of things more ingenious than those of the Greeks. Earlier, in the late 4th or early 5th century, the anonymous Hindu author of an astronomical handbook, the ''Surya Siddhanta'', had tabulated the sine function (...)" in fourteen chapters.Plofkerpp. 71–72 The ''Surya Siddhanta'' describes rules to calculate the motions of various planets and the moon relative to various constellations, diameters of various planets, and calculates the orbits of various astronomical bodies. The text is known from a palm-leaf manuscript, and several newer manuscripts. It was composed or revised c. 800 CE from an earlier text also called the ''Surya Siddhanta''. The ''Surya Siddhanta'' text is composed of verses made up of two lines, each ...
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Nowruz
Nowruz ( fa, نوروز, ; ), zh, 诺鲁孜节, ug, نەۋروز, ka, ნოვრუზ, ku, Newroz, he, נורוז, kk, Наурыз, ky, Нооруз, mn, Наурыз, ur, نوروز, tg, Наврӯз, tr, Nevruz, tk, Nowruz, uz, Navro'z is the Persian-language term for the day of the Iranian New Year, also known as the Persian New Year. It begins on the spring equinox and marks the beginning of Farvardin, the first month of the Solar Hijri calendar (an Iranian calendar used officially in Iran and Afghanistan). The day is celebrated worldwide by various ethnolinguistic groups and falls on or around the date of 21 March on the Gregorian calendar. The day of Nowruz has its origins in the Iranian religion of Zoroastrianism and is thus rooted in the traditions of the Iranian peoples; however, it has been celebrated by diverse communities for over 3,000 years in Western Asia, Central Asia, the Caucasus, the Black Sea Basin, the Balkans, and South Asia. Presently, ...
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March Equinox
The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (spring equinox) in the Northern Hemisphere and as the autumnal equinox in the Southern Hemisphere. On the Gregorian calendar, the northward equinox can occur as early as 19 March or as late as 21 March at 0° longitude. For a common year the computed time slippage is about 5 hours 49 minutes ''later'' than the previous year, and for a leap year about 18 hours 11 minutes ''earlier'' than the previous year. Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than one day from 20 March each year. The March equinox may be taken to mark the beginning of astronomical spring and the end of astronomical winter in the Northern Hemisphere but m ...
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Coptic Calendar
The Coptic calendar, also called the Alexandrian calendar, is a liturgical calendar used by the Coptic Orthodox Church and also used by the farming populace in Egypt. It was used for fiscal purposes in Egypt until the adoption of the Gregorian calendar on 11 September (6 Nesi) 1875. This calendar is based on the ancient Egyptian calendar. To avoid the calendar creep of the latter (which contained only 365 days each year, year after year, so that the seasons shifted about one day every four years), a reform of the ancient Egyptian calendar was introduced at the time of Ptolemy III (Decree of Canopus, in 238 BC) which consisted of adding an extra day every fourth year. However, this reform was opposed by the Egyptian priests, and the reform was not adopted until 25 BC, when the Roman Emperor Augustus imposed the Decree upon Egypt as its official calendar (although initially, namely between 25 BC and AD 5, it was unsynchronized with the newly introduced Julian calendar which ha ...
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