The work of medieval Eastern astronomers, including Central Asian scientists, has a special place in the development of world astronomy. During this period, Central Asian scholars, especially Uzbeks, left a very rich legacy, especially on the theory of motion of the Sun, Moon and planets, practical astronomy on determining the geographical coordinates of time and place. During this period, hundreds of great thinkers from Muslim countries were engaged in research in astronomy, mathematics and philosophy. Among them are Muhammad al-Khwarizmi, Ahmad al-Farghani, Abu Nasr al-Farabi, Abu Rayhan Beruni, Abu Ali ibn Sina, Umar Khayyam, Abu Mahmud Hamid al-Khojandi, Nasiruddin at-Tusi, Mahmud al-Chag. Famous figures such as Mini, Qazizoda Rumi, Giyosiddin Jamshid Kashi, Ulugbek, with their works and scientific heritage, have become the wealth not only of the peoples of Central Asia, but also of the peoples of the world, and today are revered among all peoples of the world.
The Baghdad Observatory, first established during the reign of Caliph Ma'mun (ninth century) and operated by Al-Khwarizmi, followed by the observatories of Umar Khayyam in Isfahan, Nasir al-Din al-Tusi in Maragha, and Abu Mahmud Hamid al-Khojandi, and finally Among them, the scientific heritage of the Ulugbek Observatory and its school, the size of which is superior to all in terms of accuracy of the main astronomical instrument, recognized an important stage in the formation of astronomy as a science in the Middle Ages.
The enthusiastic activity of Eastern astronomy, which lasted almost seven centuries, ended with the rich scientific heritage of Ulugbek and his academy. When the observatory was launched, the accuracy of its main "telescope" was only a few arc seconds, and until the invention of optical telescopes in the XVII century, its results served as a record for astronomical observations for medieval astronomers. This instrument took the theories of motion of the Sun, Moon, and planets to a new level, allowing them to achieve high accuracy in measuring time, which is one of the main subjects of eclipse theory and applied astronomy.
For hundreds of years after the great legacy of the Ulugbek School of Astronomy, Ziji Jadidi Koragoniy, scientists from many major observatories not only in the East but also in the West have used it as a program.
History of observatory construction
Usually in the Middle Ages, there were astrologers in every royal palace. Astrologers observed celestial bodies for astrological purposes, studying the positions of the Moon, stars, and planets, and making "predictions" about the fate of courtiers, the country, and the kingdom. In particular, it is known from historical sources that astrologers such as Mawlana Ahmad and Mawlana Abdullah worked in the palace of Amir Temur. Of these, Mawlana Ahmad, who also ruled the palace, predetermined the 200-year condition of the planets and prepared tables for their use for various purposes. Consequently, in the Middle Ages, it was very important for astrologers to match the results obtained from observations with the pre-calculated states of the planets.
With this in mind, there was a need to update the tables based on the results of observations made in observatories launched in the East in the IX-XII centuries. This, in turn, required the construction of new, observatories equipped with powerful astronomical instruments that would give accurate results. As a result, Genghis Khan's grandson, the astrologer of the Hulagu Khan's palace, the famous scientist Nasir al-Din al-Tusi, built an observatory in the XNUMXth century in Maragha, near present-day Tabriz (Iran), Azerbaijan. On the basis of many years of observations, Tusi prepared new astronomical tables and dedicated them to Huloguhan and called them "Ziji Elkhani". However, it soon became clear that by the end of the fourteenth century, the data in the tables compiled by Nasir al-Din began to differ significantly from the results of the observations. In this regard, there was a need to build an observatory that would provide more accurate data, better and more accurate astronomical devices than before.
In view of this, the mathematician and astronomer Giyosiddin Jamshid, who lived in Kashan, the country ruled by Ulugbek's father Shahrukh, developed the "Ziji Elkhaniy" (improvement of the "Ziji Elkhaniy"). finished his famous pamphlet. This work, written in 1413, was dedicated to Ulugbek's father Shahrukh. The theoretical part and astronomical tables of Hakan Ziji were slightly different from such parts of Ziji Elkhani and enriched with new information.
However, these corrections could only ensure the accuracy of the findings of the Sun, Moon, and planets for a few years. In order to accurately predict the positions of the Sun, Moon, and planets over decades, we need to determine their orbital elements (the Sun's annual apparent path to the ecliptic, their periods, the moments when the Moon and the planets cross the ecliptic, it was necessary to redefine the inclination of the ecliptic to the celestial equator, the exact location of the spring equinox, which is important for observations, and several other astronomical magnitudes). This, in turn, determines the coordinates of the Sun, Moon and planets, the geographical longitude and latitude of the earth, the times of solar and lunar eclipses, the times of approach and "joining" of the Moon and planets to make astrological predictions. the year of the star and the lengths of the tropical year were considered very important for the precise determination of the seasons. To address these issues, the launch of a high-precision astronomical instrument that would allow observations and measurements, i.e. the construction of a new observatory, was a pressing issue for astronomers.
The intention to build a new observatory on the territory of Shahrukh's country had long been burning Giyasiddin Jamshid Kashi, a Kashan man known at the time for his several notable works in mathematics and astronomy. Therefore, it is believed that Kashi not only expressed his respect for Shah Rukh through his Zij, but also told him that there were plans to build a new observatory. However, the outbreak of disputes over the throne among his descendants on the occasion of Amir Temur's death, including the revolt against the governor of Kashan and its surrounding provinces Said Waqqas Shahrukh in 1415, prevented him from embarking on such good deeds.
His son Iskander (Shahrukh's eldest nephew), who was appointed governor of Fergana in 1399 by Timur's decree, took advantage of Said Vaqqas's march towards Azerbaijan and invaded and conquered Jamshid Kashi's homeland, Kashan. Jamshid Kashi, who now remained in the country ruled by Alexander, appealed to Alexander in the winter of 1415 with a plan to build an observatory. After obtaining Alexander's consent, Academician Barthold discovered that in January 1416, Cauchy wrote a pamphlet, A Review of Astronomical Instruments, which described the astronomical instruments needed to equip the observatory, and presented it to Alexander, giving him a new observatory. puts forward a proposal to build. However, due to the untimely death of Alexander, Cashi's plan did not materialize this time either.
This work, written in Persian, was added to the work of academician W. Barthold "Ulugbek and his time", published in 1918 in Petrograd. In the early 1940s, Cauchy's mentioned pamphlet was written by the orientalist, astronomer G. The fifth of the instruments proposed for the observatory, first translated by Jalolov, was invented in the 1th century by our compatriot astronomer Abu Mahmud Hamid ibn Khidr al-Khojandi, and was built at the foot of Mount Tabarak near the Iranian city of Ray. ("Suds" - one-sixth of the Arabic, that is, 6/XNUMX of the arc of the circle - means a sextant). At that time, Khojandi's observatory was located in the territory of the Fakhr ud-Dawla kingdom, and since it was built under his leadership, the instrument was named "Sudsi Fakhriy".
Formation of Ulugbek school
According to the astronomer G. Jalolov, Kashi was invited to Samarkand by Ulugbek after the death of Alexander in the summer of 1416. Orientalists B. Rosenfeld and G. Matvievskaya say that Kashi came to Samarkand in 1417. In any case, when Kashi arrived in Samarkand, he informed Ulugbek that he intended to build an observatory there, and handed him the pamphlet "Review of Astronomical Instruments" intended for the construction of the observatory. Historian Salih Zaki explains the reason for this request: "Ulugbek states that he has heard many times from Giyosiddin Jamshid that the information given in" Ziji Elkhoniy "does not correspond to the results of the latest observations."
As a result, Ulugbek, who had a great knowledge of mathematics and astronomy, agreed to build an observatory. In this regard, Ulugbek gathered many scientists and in 1417 convened a meeting dedicated to the construction of the observatory. Historian Abdurazzaq Samarkandi, a contemporary of Ulugbek on the construction of the observatory, writes about this assembly: “The assembly should build the future observatory in such a way that it does not shake over time, does not move, and lasts for many years. For this (construction of an observatory) (meeting) indicated a favorable location from the North-East of Samarkand. Until its construction is completed, the following should be done: to improve the knowledge of future employees of the observatory, to create additional tables and to prepare the necessary (monitoring) equipment uz ”.
Unfortunately, there is no clear information from historical sources about the date of construction of the Ulugbek Observatory, which puts an end to the controversy so far. W. Barthold concludes from the words of the historian Abdurazzaq about the events of 1420 in "Ulugbek and his period" and concludes that the construction of the madrasah and observatory was completed in 1420. Archaeologist V. Shishkin talks about three coins found by him in the south during the excavation of the remains of the observatory, two of which have the inscription 823 AH (1420 CE) on the edge. According to Mirkhand in Ravzat us-safo, given that the observatory was built at a rapid pace, it is clear that it was built in 1420 or 1421. In Salih Zaki's Osar al-Baqiya, Ulugbek named Giyosiddin Jamshid and Qazizada Rumi as leaders in the observatory built in 824 AH (1420 CE).
appointed. In the foreword to Ziji Guragoni: “We have resolved the issue of lighting monitoring. We did them in collaboration with Qazizada Rumi and Ghiyosiddin Jamshid muhim At the beginning of writing and formalizing an important work (“Zij”) (G. Jalolov translated the Persian words “fake and fake” and gave him some examples) iyosiddin, later Rumi died in Qaziza. After that, the case was finalized together with Ali ibn Muhammad Kushchi, the precious son of (Ulugbek).
"Ziji Koragoniy" is a monument to Ulugbek Academy
Astronomer G. Jalolov, as a member of the Commission on the History of Astronomy under the Astronomical Council of the former Soviet Union, took an active part in the study of the history of Eastern astronomy in the 1950s, including the history of the Ulugbek School of Astronomy. In the first issue of his book, Studies in the History of Ziji, he published an article that fully covered the differences and advantages of Ziji Koragoniy from several other similar Zijis.
The main research work of the Samarkand Observatory consists of the preface "Ziji Koragoniy", the theoretical part and zij (tables), which occupies a total of 430 pages. The non-tabular text part of Zij is 60 pages, and the remaining 370 pages are astronomical, trigonometric, geographical and astrological tables.
The preface is only two pages long. It tells about the observatory and the scientists who participated in the preparation of Zij. The theoretical part consists of four sections (articles), the first of which was considered one of the main calendars at that time - Hijri, Yazdigird, Jalali (a calendar reformed by Malikshah in the XI century on the project of Umar Khayyam), includes Chinese, Uyghur, and several other calendars, as well as calculations on the transition from one to the other.
The second section deals with spherical and applied astronomy and describes methods for determining the azimuths of lights, the direction to Mecca, and the calculation of the longitude and latitude of settlements on Earth. Here you will find the content of these tables, guidelines and tips for their use.
The third section is devoted to the theory of motion of the Sun, Moon, and other planets. Determining their positions along astronomical longitudes and latitudes and the events associated with it, in particular, solar and lunar eclipses.
Finally, the fourth section is not very large and is devoted to information about "other astronomical works," including a few pages of astrological tables.
Among them is an important astronomical constant related to the theory of the annual apparent motion of the Sun against the background of stars — the magnitude of the angle of inclination of the Sun's annual visible path plane (ecliptic) to the celestial equatorial plane (plane parallel to the Earth's equator) a very large number of medieval astronomers were engaged in its detection. Below we present some of them and compare them with the results achieved by Ulugbek Observatory:
Navoi's contemporary astronomer Birjandi in his commentary on "Ziji Koragoniy": "With the help of the Honorary Sextant (astronomical observations) can be measured to the nearest second of the arc. Astronomers from Samarkand measured the mentioned deviation (deviation of the ecliptic to the celestial equator - MM) using the Honorary Sextant. In it, the distance of the Sun from the zenith is determined during its culmination (i.e., during a clear dream). Based on the measurement of this arc distance, they found that the magnitude of this deviation changes over time.
Birjandiy also writes about the ecliptic deviation in his book "Commentary to Asturlob": "The ecliptic deviation varies in size at different times." managed to get the value. It should be noted that the angle of inclination of the ecliptic to the equator changes over time (decreases in the Middle Ages), and its value for the time of Ulugbek is 23o 30 ′ 17 ″. Therefore, the error of Samarkand scientists in this regard is only 23 arc seconds, which is a very high accuracy.
The main "telescope" of the Ulugbek Observatory was that the plane of the sextant had to be set along the exact meridian plane, ie the azimuth had to be zero. In 1941 and 1946, measurements were made using modern instruments to determine how accurately this problem was solved in the Middle Ages. As a result, the azimuth of the sextant axis (i.e., the axis of the Universe, the inclination to the plane of the celestial meridian passing through the zenith - MM) was 7,5. Although this error had almost no effect on the value of the heights of the lights on the meridian, it did result in an error of up to 30 seconds at noon.
Academician VPShcheglov, director of the Tashkent Astronomical Observatory, wrote about this error: “During the reign of Ulugbek, the instrument was precisely mounted along the meridian, probably during five centuries the azimuth of the instrument plane changed, various events (earthquakes, sinking of the device, etc. - MM) may have occurred due to deformation of the device. It should be noted that the meridian direction for the sextant of the Ulugbek Observatory is the only and most ancient device on Earth, which was found with the highest accuracy for that period.
Scientists from the Ulugbek School found that the latitude of the observatory was 39o 37 ′ 28 ″. However, when VPShcheglov made observations using precision optical devices in the 1940s to redefine the value of this magnitude, it turned out to be 39o 40 ′ 40 ″. In other words, in the Middle Ages, only 3,2 ′ ′ error was made in measuring the width of the Samarkand Observatory.
The geographical coordinates of many settlements on the border of the Arab and Persian Eastern countries were found on the basis of astronomical observations, and the coordinates of places outside the caliphate mentioned in Zij were apparently given on the basis of data given in previous Zij.
Ziji Koragoniy's tables on the positions of the Sun, Moon and planets, the tables of more than a thousand directly visible stars, were mostly the result of direct observations by scientists at the Samarkand Observatory and were among the most accurate tables of medieval astronomy. Therefore, in the Middle Ages, the manuscript "Ziji Koragoniy" began to be copied and reproduced at great speed in various places.
Speaking about Ulugbek Ziji, Babur noted that the work was one of the most widespread astronomical tables in the world in the XVI century. Especially in recent centuries, the accuracy of the catalog of stars belonging to "Ulugbek Ziji" has aroused great interest among many Western astronomers.
In the 1000nd century BC, a table of stars reflecting the coordinates and brightness of more than 1028 stars was compiled by the Greek astronomer Hipparchus. This catalog was later determined to some extent by the famous Egyptian astronomer Ptolemy (second century AD), and the number of stars reached XNUMX.
Abu Husayn ibn 'Umar al-Sufi (903-998), who lived and worked in Ray, was one of the first to determine the coordinates and clarity of the 1017 stars mentioned in Ptolemy's book Al-Majisti, and to draw an atlas of stars through an allegorical depiction of the relative positions of the constellations. formed.
The star catalog of Ziji Koragoniy contains 1018 stars, which are arranged according to the constellations of Beruni as in the star catalog. This table is well studied by the Uzbek astronomer G. Jalolov. According to the scientist, the As-Sufi catalog was widely used in this "Zij" to determine the magnitudes that characterize the brightness of the stars.
Astronomer G. Jalolov quotes the following words from "Zij": "The stars we have mentioned in our catalog were replaced by the beginning of 841 AH (ie, the 1st of Muharram, which is the 1437th of July 4 in the melodic account). ri comes - G'.J.) relative. However, given that their correct outputs (the coordinates associated with the position of the spring equinox) are 70 degrees ahead in the solar year (in terms of the coordinates called the correct outputs - MM), at any time We can clearly find the place of each of them. "
Accordingly, this phenomenon, known as precession in astronomy, which is associated with a change in the correct output of stars (precession, is a period of 26 millennia around the ecliptic axis of the Earth's axis). It should be noted that Samarkand astronomers are not only well aware of this delicate phenomenon, which occurs due to its rotation and is very difficult to predict even in 5-10 years due to its small size. To find the magnitude of the precession they determined, it is necessary to divide the displacement equal to 70o found in 1 by 70 solar years, i.e. 1o: 70 = 3600 ″: 70 = 51 ″, 4. In fact, given that the size of the precession is 50 ″, 2, it is clear that the error made by the scientists of the Ulugbek school in this regard is only 1,2 ″. This was a great clarity for medieval astronomy.
The table of the stars "Ulugbek Ziji" was studied in detail by the American orientalist E. Noble, who studied at the Samarkand Observatory in astronomical longitude 900, latitude878 stars have been studied, and the coordinates of the remaining stars have been determined by longitudinal correction from the As-Sufi catalog of stars.
Only 430% of the 5-page Ziji Koragoniy is a star chart. It should be noted that the main task of astronomers of the Samarkand Observatory is not to create a catalog of stars, as many think, but to study the Sun, Moon and planets (including Utorud, Venus, Mars, Client and Saturn). on the basis of systematic observation, the main constants in astronomy were to find the exact values of the ecliptic's inclination to the equator, the annual process, the length of the stellar year, and many other similar astronomical quantities.
About 80 percent of the Ziji Vision tables are dedicated to the Sun, Moon, and five planets. Based on the data in this table, at the end of "Ulugbek Ziji" there are several tables necessary for the needs of astrology. In this regard, Navoi's contemporary astronomer Abd al-Ali Birjandi in his commentary on "Ziji Koragoniy" said: "The task of astronomers is to study the movement of the seven lights mentioned above, to determine their basic constant quantities. The ultimate goal is to determine their future position based on these magnitudes and predict events that will occur depending on their position on Earth in the sky. ”
In order to predict the timing of various astronomical events, especially solar and lunar eclipses, it is necessary to determine the longitude and latitude of the cities and settlements where these eclipses are observed. "Ziji Koragoniy" -
The coordinates of 247 cities and settlements are given in It is difficult to say how many cities' geographical coordinates were directly determined by observatory scientists. This is because a certain part of the cities mentioned in Zij is also mentioned in Nasir al-Din al-Tusi's Ziji Elkhani.
Scientists of the Samarkand Academy have chosen the lunar-Hijri calendar as the exact calendar in compiling the Ziji Koragoniy tables. The moon, the sun, and the planets were taken as the beginning of the month of Muharram in 841 AH, in other words, the beginning of the new year, the day of the new year. . This day falls on July 1437 (Thursday) in 4 AD. Considering this period as the equinox of the stellar catalog, firstly, that this day corresponds approximately to the middle of the period of astronomical observations at the Samarkand Observatory (1420-1450); secondly, this equation coincided with the beginning of the next 30-year cycle (order 29 cycles) adopted to mark the leap years of the Hijri calendar. The Zij tables give changes in the positions of the Sun, Moon, and some other data for the years 841-871 (i.e., the years of the full 30-year cycle), which was important because of the ease of use of these tables.
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Engraving in the book "Astronomical Tree" by Jan Heveli (XVII century).
The god of astronomy is Uranus in the middle. To his right are Mirzo Ulugbek, Wilhelm IV (German scientist), Jan Geveli. On the left are Ptolemy, Ticho Brage (Danish astronomer), Richchi Ole (Italian scientist).
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A look into the depths of the Universe from an observatory set up by Ulugbek and his comrades at the foot of Samarkand, a great city almost six centuries ago, reveals the "undiscovered reserve" of world science and culture - the study of the universe was a big step forward. The reason for this first step was the launch of a series of large, well-equipped observatories in Europe. The heliocentric theory of the structure of the universe in Poland (by N. Copernicus), the idea of the infinity of the universe in Milan (Italy) and the fact that the solar system is a system formed by the satellites of a simple star (by Jordano Bruno), the sky representing the laws of motion of celestial bodies in Germany Mechanics (by I. Kepler), the method of calculating the masses of celestial bodies in England (by I. Newton) were the first streams of Samarkand astronomers to study the movements of the Sun, Moon and planets. Ulugbek's school made a great contribution to the formation of a special science called theoretical astronomy.
Exploring the universe, being aware of its mysteries, is important as it fulfills the function of worldview, such as determining the purpose of man's coming to Earth. He said that man is a part of the infinite universe and the product of its evolution over billions of years, that the life he lived is only a minute before the age of the universe, that the "instantaneous" life of every human being is miraculous, and that this "instantaneous" life It is of paramount importance in that it realizes the need to live for great goals, not to be thrown away, and to live without tarnishing this great name.
This, in turn, allows a person to appreciate his life, the fate and personality of others, a rare gift of nature - not to take life lightly, to act with great noble goals, to enrich its content with his positive activities. , encourages content.
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