|
Jalali Calendar
The Jalali calendar, also referred to as ''Malikshahi'' and ''Maliki'', is a solar calendar compiled during the reign of Jalaluddin Malik-Shah I, the Sultan of the Seljuk Empire (1072–1092 CE), by the order of Grand Vizier Nizam al-Mulk, using observations made in 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. The Jalali calendar gains approximately 1 day on the Julian calendar every 128 years. The tropical Jalali calendar (), which inherited some aspects from the Yazdgerdi calendar, was adopted on 15 March 1079 by the Sultan, based on the recommendations of a committee of astronomers, including Omar Khayyam, at the imperial observatory in the capital city of Isfahan. It was Khayyam who positioned Isfahan as the prime meridian, otherwise known as the nasf. Month co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Calendar
A solar calendar is a calendar whose dates indicates 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. Examples The oldest solar calendar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isfahan Observatory
The Isfahan Observatory ( Persian: رصدخانه اصفهان) or Malikshah Observatory (رصدخانه ملکشاه) was an astronomical observatory constructed during the reign of Sultan Malik Shah I by Omar Khayyam, closing shortly after his death in 1092. It was from the work at the observatory that the Jalali Calendar was adopted. Aside from the work on the calendar, little is known about the purpose of the observatory, as no comprehensive sources from its time period are known to exist about the work performed there. History In 1073, Malik Shah invited the astronomer-poet-mathematician Omar Khayyam to oversee an observatory being constructed in Isfahan. The observatory was completed and began operating in 1074. It was scheduled to operate for thirty years, the length of Saturn's revolution around the Sun. Five years after research began, in 1079, Khayyam revealed his corrected calendar and a zīj (a book used for calculating planetary positions), both named after the Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armenian Calendar
The Armenian calendar is the calendar traditionally used in Armenia, primarily during the medieval ages. Since 1918, the civil calendar in Armenia is the Gregorian calendar. The Armenian calendar was based on an invariant year length of 365 days. Because a solar year is about 365.25 days and not 365 days, the correspondence between the Armenian calendar and both the solar year and the Julian calendar slowly drifted over time, shifting across a year of the Julian calendar once in 1,461 calendar years (see Sothic cycle). Thus, the Armenian year 1461 ( Gregorian & Julian 2011) completed the first Sothic cycle, and the Armenian Calendar was one year off. In A.D. 352, tables compiled by Andreas of Byzantium were introduced in Armenia to determine the religious holidays. When those tables exhausted on 11 July 552 (Julian Calendar), the Armenian calendar was introduced. Year 1 of the Armenian calendar began on 11 July 552 of the Julian calendar. The calendar was adopted at the Secon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Hijri Calendar
The Solar Hijri calendar is the official calendar of Iran. It is a solar calendar, based on the Earth's orbit around the Sun. Each year begins on the day of the March equinox and has years of 365 or 366 days. It is sometimes also called the Shamsi calendar, Khorshidi calendar or Persian calendar. It is abbreviated as SH, HS, AP, or, sometimes as AHSh, while the lunar Hijri calendar (commonly known in the West as the 'Islamic calendar') is usually abbreviated as AH. The epoch (very first day) of the Solar Hijri calendar was the day of the spring equinox, March 19, 622 CE. The calendar is a "Hijri calendar" because that was the year that Mohammed is believed to have left from Mecca to Medina, which event is referred to as the Hijrah. Since the calendar uses astronomical observations and calculations for determining the vernal equinox, it theoretically has no intrinsic error in matching the vernal equinox year. According to Iranian studies, it is older than the lunar Hijri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iranian Calendars
The Iranian calendars or Iranian chronologies (, ) are a succession of calendars created and 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 many times for administrative purposes. The most influential person in laying the frameworks for the calendar and its precision was the 11th century Persian polymath, Omar Khayyam. The modern Iranian calendar is the Solar Hijri calendar, currently the official civil calendar in Iran. Nowruz, 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 of Tehran (52.5°E). Thus the calendar is observation-based, unlike the Gregorian calendar, 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, UTC+03:30. Ancient calendars The earliest evidence of Ir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ephemeris
In astronomy and celestial navigation, an ephemeris (; ; , ) is a book with tables that gives the trajectory of naturally occurring astronomical objects and 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 time, positions for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hindu Calendar
The Hindu calendar, also called Panchangam, Panchanga (), 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, 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 Shaka era, Shalivahana Shaka (Based on the Shalivahana, King Shalivahana, also the Indian national calendar) found in the Deccan Plateau, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surya Siddhanta
The ''Surya Siddhanta'' (; ) is a Sanskrit treatise in Indian astronomy dated to 4th to 5th century,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 probably c. 800 CE from an earlier text also called the ''Surya Siddhanta''. The ''Surya Siddhanta'' text is composed of verses mad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nowruz
Nowruz (, , () , () , () , () , Kurdish language, Kurdish: () , () , () , () , , , , () , , ) is the Iranian or Persian New Year. Historically, it has been observed by Iranian peoples, but is now celebrated by many ethnicities worldwide. It is a festival based on the March equinox, Northern Hemisphere spring equinox, which marks the first day of a new year on the Iranian calendars and the currently used Solar Hijri calendar; it usually coincides with a date between 19 March and 22 March on the Gregorian calendar. The roots of Nowruz lie in Zoroastrianism, and it has been celebrated by many peoples across West Asia, Central Asia, the Caucasus and the Black Sea Basin, the Balkans, and South Asia for over 3,000 years. In the modern era, while it is observed as a Secularism, secular holiday by most celebrants, Nowruz remains a holy day for Zoroastrians, Baháʼís, and Isma'ilism, Ismaʿili Shia Muslims. For the Northern Hemisphere, Nowruz marks the beg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (or spring equinox) in the Northern Hemisphere and as the autumnal equinox (or fall equinox) in the Southern Hemisphere. On the Gregorian calendar at 0° longitude, the northward equinox can occur as early as 19 March (which happened most recently in 1796, and will happen next in 2044), and it can occur as late as 21 March (which happened most recently in 2007, and will happen next in 2102). 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coptic Calendar
The Coptic calendar, also called the Alexandrian calendar, is a liturgical calendar used by the farming populace in Egypt and used by the Coptic Orthodox and Coptic Catholic churches. It was used for fiscal purposes in Egypt until the adoption of the Gregorian calendar on 11 September 1875 (1st Thout 1592 AM). 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 unsynchronised with the original i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
