Persian astronomy or Iranian astronomy refers to the

astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...

in ancient Persian history.

Pre-Islamic history

Ancient

Persians The Persians are an Iranian ethnic group who comprise over half of the population of Iran. They share a common cultural system and are native speakers of the Persian language as well as of the languages that are closely related to Persian. ...

celebrated the

vernal equinox Spring equinox or vernal equinox or variations may refer to: * March equinox, the spring equinox in the Northern Hemisphere * September equinox, the spring equinox in the Southern Hemisphere Other uses * Nowruz, Persian/Iranian new year which be ...

summer solstice The summer solstice, also called the estival solstice or midsummer, occurs when one of Earth's poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere ( Northern and Southern). For that hemisphere, the summer ...

, autumnal equinox, and

winter solstice The winter solstice, also called the hibernal solstice, occurs when either of Earth's poles reaches its maximum tilt away from the Sun. This happens twice yearly, once in each hemisphere ( Northern and Southern). For that hemisphere, the winte ...

through a variety of different festivals and traditions.

Vernal equinox

Nowruz is the day of the

and the moment the Sun crosses the celestial equator has been calculated for years. Nowruz was an important day during the

Achaemenid period The Achaemenid Empire or Achaemenian Empire (; peo, 𐎧𐏁𐏂, , ), also called the First Persian Empire, was an ancient Iranian empire founded by Cyrus the Great in 550 BC. Based in Western Asia, it was contemporarily the largest emp ...

and continued in importance through the

Sasanian dynasty The Sasanian dynasty was the house that founded the Sasanian Empire, ruling this empire from 224 to 651 AD in Persia (modern-day Iran). It began with Ardashir I, who named the dynasty as ''Sasanian'' in honour of his grandfather (or father), Sasa ...

Summer solstice

Tirgan is an ancient Iranian festival celebrating the

Autumnal equinox

Mehregan is an ancient

Zoroastrian Zoroastrianism is an Iranian religion and one of the world's oldest organized faiths, based on the teachings of the Iranian-speaking prophet Zoroaster. It has a dualistic cosmology of good and evil within the framework of a monotheistic on ...

and Persian festival celebrating the autumnal equinox since at least the

4th century BC The 4th century BC started the first day of 400 BC and ended the last day of 301 BC. It is considered part of the Classical era, epoch, or historical period. This century marked the height of Classical Greek civilization in all of its aspects ...

Winter solstice

Yaldā Night is an ancient Iranian festival celebrating the

of the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

Star systems

Some old

Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples ** Persian language, an Iranian language of the ...

names in astronomy have barely survived; the names of the four

Royal stars In astrology, the royal stars of Achaemenid Empire, Persia are Aldebaran, Regulus, Antares and Fomalhaut. They were regarded as the guardians of the sky during the time of the Persian Empire (550 BC–330 BC) in the area of modern-day Iran. The Pe ...

that were used by the Persians for almanacs are Aldeberan,

Regulus Regulus is the brightest object in the constellation Leo and one of the brightest stars in the night sky. It has the Bayer designation designated α Leonis, which is Latinized to Alpha Leonis, and abbreviated Alpha Leo or α Leo. Re ...

, Antares and Fomalhaut, and are thought by scientists to equate to the modern-day

star systems A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a ''star cluster'' or ''galaxy'', although, broadly speaking, ...

Alcyone In Greek mythology, Alcyone or Halcyone (; grc, Ἀλκυόνη, Alkyónē derived from grc, ἀλκυών, alkyṓn, kingfisher, label=none) and Ceyx (; grc, Κήϋξ, Kḗÿx) were a wife and husband who incurred the wrath of the god Zeus ...

Albireo Albireo is a double star designated Beta Cygni (β Cygni, abbreviated Beta Cyg, β Cyg). The International Astronomical Union uses the name "Albireo" specifically for the brightest star in the system. Although designated ' beta', ...

, and Bungula (Alpha Centauri) for almanacs.

Planets

Tablet Tablet may refer to: Medicine * Tablet (pharmacy), a mixture of pharmacological substances pressed into a small cake or bar, colloquially called a "pill" Computing * Tablet computer, a mobile computer that is primarily operated by touching the s ...

inscriptions set forth observations of

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

from the 43rd year of the reign of Artaxerxes II to the thirteenth year of

Alexander the Great Alexander III of Macedon ( grc, wikt:Ἀλέξανδρος, Ἀλέξανδρος, Alexandros; 20/21 July 356 BC – 10/11 June 323 BC), commonly known as Alexander the Great, was a king of the Ancient Greece, ancient Greek kingdom of Maced ...

. The positions of the planets throughout the year were determined using astrological charts.

After Muslim conquests

After the

Muslim conquest of Persia The Muslim conquest of Persia, also known as the Arab conquest of Iran, was carried out by the Rashidun Caliphate from 633 to 654 AD and led to the fall of the Sasanian Empire as well as the eventual decline of the Zoroastrian religion. Th ...

, much of Persian astronomy and

astrology Astrology is a range of Divination, divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of Celestial o ...

became intertwined with the

astronomy in the medieval Islamic world Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age (9th–13th centuries), and mostly written in the Arabic language. These developments mostly took place in the Middle ...

, paving way for the

Islamic Golden Age The Islamic Golden Age was a period of cultural, economic, and scientific flourishing in the history of Islam, traditionally dated from the 8th century to the 14th century. This period is traditionally understood to have begun during the reign ...

. Scientists translated studies in

Sanskrit Sanskrit (; attributively , ; nominally , , ) is a classical language belonging to the Indo-Aryan branch of the Indo-European languages. It arose in South Asia after its predecessor languages had diffused there from the northwest in the late ...

Middle Persian Middle Persian or Pahlavi, also known by its endonym Pārsīk or Pārsīg () in its later form, is a Western Middle Iranian language which became the literary language of the Sasanian Empire. For some time after the Sasanian collapse, Middle Per ...

, and Greek into

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

, where the Indian Sanskrit and Persian Pahlavi (Middle Persian) sources taught medieval astronomers methods for calculating the position of heavenly bodies, and for creating tables recording the movement of the sun, the

moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, and the five known planets. The first major Muslim work of astronomy was ''Zij al-Sindhind'' by Persian mathematician al-Khwarizmi in 830. The work contains tables for the movements of the Sun, the moon and the five planets known at the time, and is significant as it introduced

Ptolemaic Ptolemaic is the adjective formed from the name Ptolemy, and may refer to: Pertaining to the Ptolemaic dynasty * Ptolemaic dynasty, the Macedonian Greek dynasty that ruled Egypt founded in 305 BC by Ptolemy I Soter * Ptolemaic Kingdom Pertaining ...

concepts into Islamic sciences. This work also marks the turning point in Islamic astronomy. Hitherto, Muslim astronomers had adopted a primarily research approach to the field, translating works of others and learning already discovered knowledge. Al-Khwarizmi's work marked the beginning of nontraditional methods of study and calculations.Dallal (1999), pg. 163

References

{{Astronomy navbox Astronomy in Iran Persian culture Iranian culture