Islamic Astronomy of Abbasid Era (750-1258 AD)

Astronomy is a particular field in Islam related to the interests of daily Muslim worship practices, such as determining the beginning of prayer times, qibla direction, and the beginning of the Qamariyah month. During the Abbasid period 750-1258 AD, especially during the reign of Abu Ja'far Al-Mansur, Harun Al-Rashid, and Al-Ma'mun, Islamic astronomy developed significantly. This can be seen from the emergence of astronomers. The love of the three Abbasid caliphs for science significantly influenced the policies related to development in science. The method used in this study is a qualitative method with historical analysis techniques. This study aims to add to the enrichment of historical treasures related to the development of science, especially astronomy, during the Abbasid period. Meanwhile, astronomy during the Abbasid period also had many scientific sources that needed to be studied more comprehensively. That is, many scientific figures in astronomy have never been specifically studied. Therefore, the study of astronomy today in higher education must also seriously focus on learning classical knowledge. This paper discusses the Abbasid state in developing science during its reign by looking at it from the perspective of significant scientific developments during the leadership of its caliph, which was indirectly influenced by socio-religious and intellectual conditions in his time. During the Abbasid era, the progress of science had reached its golden age, especially in Islamic astronomy which had contributed to the development of its science in the field of astronomy in the period after that until now.


Introduction
The history of Islamic civilization in classical times provides a unique pattern in the reality of its culture and society, especially in the Abbasid era. Some historical literature shows that the Abbasid state that once ruled from 750-1258 AD (Sunanto M., 2003, p. 50) , was the state that stood after the collapse of the Umayyad state. The Abbasid state, in its development, showed glory in the field of culture and civilization. The astonishing achievements can be seen from the periodization of the reign of the caliphs. Some of the progress achieved by the Abbasid state include economics, politics, military, and education (science). The achievements of the Abbasid period can still be enjoyed to this day, especially in the academic field.
The rule of the Abbasid state once reached a golden age. Politically the caliphs were compelling figures who were influential in the center of political power and religion. On the other hand, the prosperity of society reaches the highest level. The first period of the Abbasid period succeeded in preparing the foundation for the development of science in Islam. Islamic civilization and culture grew, developed, and even flourished in the Abbasid period. This rapid development is because the Abbasid Dynasty in the early period emphasized the development of Islamic civilization and culture rather than the expansion of territory. The focus on establishing society is one of the differences between the Umayyad and Abbasid states (Wandi, 2020, p. 72).
Scientifically, the Abbasid era was quite prominent. The prominence of the Abbasid Caliphate can be seen from the developments of science that have been achieved. The extraordinary achievements of Muslims before the Abbasid state were achieved during the Umayyad state. Some of the evidence, among others, such as the conquest of the territories of the Roman and Persian empires. It was followed by even more outstanding achievements in mastery in the field of science in the next century. The study of science that began with the Umayyad became a massive undertaking during the Abbasid era. Conditions at the time of the Abbasid had Journal of Islamic History and Manuscript Volume 01, Number 01, April 2022 made it possible to do this, considering that the Arabic language had reached perfection. (Machfud Syaefudin, 2013, p. 75) Several achievements in the field of knowledge were pioneered by the Abbasid rulers who gave direct support and contributed to its development, including Ja'far Al-Mansur, and Harun Al-Rashid.
During the time of Ja'far Al-Mansur, the movement to build knowledge on a large scale began to be intensified (Gurabi, 1959, p. 137) precisely after establishing the city of Baghdad in 762 AD. The discipline of astronomy could not be separated from developments that received special attention from the Abbasid caliphs, especially during the caliphate. Al-Ma'mun.
The study of Islamic astronomy during the Abbasid period has not been discussed explicitly in the contemporary era. However, the development of astronomy in this era still needs to be traced to its historicity. Therefore, the relocation of the capital city is intended to make the center of government safer (Karim, 2011, p. 144). In addition, the election of Baghdad as the center of the Abbasid state government was based on political, security, social and geographical considerations. Damascus, Kuffah, and Basra, which had developed earlier, were not chosen because in these cities, there were still political opponents of the Abbasid State (al-Aziz, 2014, p. 197). When viewed from the division of historical periodization, the first Abbasid period is the best period starting from Abu Abbas as-Saffah and ending with Al-Watsiq.
Three things show the ability of the Abbasid caliphate to develop culture.
Civilization in government, among others, are as follows: a) strengthening the foundations of the Abbasid State and crushing all attempts to seize power, b) enforcing Islamic law, which is relatively successful in uniting all elements of society at that time, c) protecting Islam and its civilization (al- 'Ilm, 2011, p. 93). However, the popularity of the Abbasid State reached its peak during the caliphate Harun Al-Rashid and his son Al-Ma'mun.
At the time of Al-Mahdi, the economy began to show development, which can be seen from the increase in the agricultural sector and mining products such as silver, gold, copper, and iron. While its popularity peaked at the time of Harun Al-Rashid, many educational institutions and social needs began to be established. It shows social welfare, health, education, culture, and science. After Harun's reign, the leadership relay was held by Al-Ma'mun, who showed significant scientific developments (Yatim, 2018, pp. 52-53).
During the reign of Al-Ma'mun, the translation of foreign works began to be encouraged. Such as the translation of Greek books, as well as the establishment of many schools and his greatest work was the construction of Bait al-Hikmah, as a translation center that functioned as a college with a large library. At the time of Al-Ma'mun, Baghdad began to become a center of culture and science (Watt, 1990, p. 68 in full force (Syalabi, 1993, p. 309). As described above, the peak of Islamic culture and thought development occurred during the reign of Bani Abbas. However, not all of them started from the creativity of the ruler of Bani Abbas himself. But some have been built in the early days of the Islamic revival (Yatim, 2018, p. 54).

Social-Religious and Intellectual Conditions of The Abbasid Time
During the reign of the caliph Al-Mansur, the country's capital, which was initially Al-Hashimiyah, close to Kufa, was moved to Baghdad for more profitable reasons. The vast geographical area of the Islamic world stretches from East to West, indirectly influencing the occurrence of social interactions between residents of each region and others. The interaction process allows for the assimilation of Arab culture with other nations, from the assimilation process that has taken place effectively and has practical value in the development of Islamic civilization. During the reign of Bani Abbas, many non-Arab nations embraced Islam (Yatim, 2018, p. 55). This event was motivated by the development of social interactions, including through mixed marriages and cultural exchanges. The poem shows that Arab historians were too concentrated on the issue of the caliphate and political events, so it did not provide an overview of the social life of most people at that time (Hitti, 2018, pp. 414-415).
The Abbasid rulers formed a society based on a sense of equality, the class division in society during the Abbasid era was not very visible. This can be proven by the issue of choosing a wife and mother for the children of the Abbasid's caliphs. Abbasid families who were born to independent mothers were Abu al-Abbas, al-Mahdi, and al-Amin. Among the caliphs of the Abbasid State, Al-Mansur's mother was a Berber slave, Al-Ma'mun's mother was a Persian slave, Al-Watsiq and Al-Muhtadi's mother was of Greek origin, Al-Muntashir's mother was a Greco-Abyssinian, and Harun's mother also slaves from other countries, known as al-Khayzuran the first woman who had great influence in the state affairs of the Abbasid State (Hitti, 2018, p. 414 such as medicine, manthiq (logic), outer space science, sports science, astronomy, and other sciences related to social problems of Muslims (Karim, 2011, pp. 174-175).
During the reign of Caliph Harun Al-Rashid, much of the wealth was used for social purposes, hospitals, medical, educational institutions, and pharmacies. At the time, there were about 800 doctors. In addition, public baths were also built. If we look at this reality, the period of Aaron's caliphate is a manifestation of prosperity in the Abbasid era by considering various walks of life, including social welfare for its people (Yatim, 2018, p. 52).
By the time the Abbasid caliphate was in power, the strong wave of Muslim conquerors had run out of energy. When the Abbasids experienced a decline in power in Baghdad, it did not reduce the influence of Islam, which had taken root and multiplied its adherents. Meanwhile, in its development, the number of regions subject to Islamic rule increased and reached its peak in the sixteenth and seventeenth centuries. However, some success was offset by the loss of both areas and adherents (Levy, 1986, pp. 28-29).
Journal of Islamic History and Manuscript Volume 01, Number 01, April 2022

The Contribution of The Abbasid Caliphate to The Development of Astronomic
Ten (X) century A.D. is often referred to as the century of Islamic development where the Islamic world, from Cordoba in Spain to Multan in Pakistan, experienced growth in various fields, especially in the areas of science, technology, and art. The Islamic world at that time was advanced, victorious, and prosperous; on the other hand, the western world was still dark, stupid, and primitive. The Islamic world is already busy conducting investigations in laboratories and observatories, while the western is still preoccupied with incantations and gods. This is because the religion brought by the Prophet Muhammad has given rise to the impetus to grow a new culture, namely Islamic culture (Sunanto M., 2003, p. 54).
The achievements of Muslims were brilliant during the Umayyad period when they were able to conquer the territory of the Roman and Persian kingdoms, which was followed by even more remarkable achievements in the conquest of the field of science in the next century. The study of science began with the Umayyads and became a massive undertaking during the Abbasid period. The conditions during the Abbasid period had made it possible to do this, considering that the Arabic language had reached perfection. Arabic letters, punctuation marks, and vocabulary is complete. The grammar is perfect. As made by China, the paper industry was cultivated during the time of Harun al-Rashid (Sunanto M., 2003, p. 56). The development of paper also spurred developments in other fields. Stability in the political area allowed the economy to develop rapidly, and development in all fields, both defense and industry and trade, increased tremendously so that the increased and abundant funds supported the development of science (Sunanto M., 2003, p. 54).
An oddity, the golden age of this field of science occurred precisely when the political situation of the Abbasid Caliphate began to decline. This causes an uncertain political problem because power has been divided by the emergence of small daulas in the outskirts (Sunanto M., 2003, p. 82 to Shiaism. However, intellectual and scientific activities were growing when the Islamic world was in decline. The reason is that political life is very dependent on implementing justice and security. While injustice often causes scholars and scientists to leave political practice and run to the field of theory and science (Sunanto M., 2003, p. 83).

Al-Fazari (D. + 777 AD)
Al-Fazari has the full name Muhammad ibn Ibrahim al-Fazari (Hitti, 2018, p. 467). He is a figure who has made a significant contribution in Astronomy. This can be seen through his writing, which began with translating the book Sidhanta from India into Arabic by Al-Fazari in Baghdad in 771 AD. Then the translation of the Pahlavi lists (zÎk) compiled since the Sasanian period continued. After that, the Greek book was translated Almagest by Ptolemy (Sunanto M., 2003, p. 103 (Hitti, 2018, p. 467).
In the early IX century A.D. an observatory with somewhat more accurate Ma'mun soon established a branch of this observatory on Mount Qosayun outside the city of Damascus (Sunanto M., 2003, p. 104).
Among the observatory's complementary instruments at that time, among others, consisted of a quadrant, an astrolabe (a tool for measuring altitude used in the Middle Ages), and a dial (a device for measuring time, speed, temperature), and a globe. Al-Fazari was the first to invent the astrolabe. This astrolabe model is probably taken from the Greek, judging from its Arabic name, Astrulab. The first published books about the astrolabe were those written by Ali ibn Isa al-Astrhurlabi, who lived in Baghdad and Damascus before 830 AD (Sunanto M., 2003, p. 104).
The astronomers al-Ma'mun demonstrated great accuracy in geodetic operations (measurement of the length of the protractor of elevation and sea level). The purpose of this operation is to determine the size of the earth and the distance around the earth with the assumption that the earth is round. These measurements were made on the Sinjar plain between the Furat river and also near Palmira, which yielded 56 2/3 Arabian miles as the arc length of a degree meridian, which is a very accurate result that can, in the extreme, determine the proper length and protractor of the place i.e. ± 2877 feet. Based on the results of this calculation, it is calculated that the distance of the earth's circle is 20,400 miles, and its diameter is 6500 miles. Among those who took part in this operation were the sons of Musa ibn Shakir and perhaps also al-Khwarizmi, whose list a century and a half later was revised by Maslamah al- Al-Battani has the full name of Abu Abdullah Muhammad ibn Jabir al-Battani (Hitti, 2018, p. 471). It is one of the most prominent comparative and diligent At-Tajibi An-Naqasy. He is a scientist who discovered what is called astronomy with the "Toledo Sheet" attributed to his city of Toledo, Spain. This note is known to have been written by earlier scientists such as Bathlemeus, Al-Khwarizmi, and others. In these notes, he recorded the conclusions of astronomical binoculars. He wrote the book "Ash-Shahifatu Az-Zaijiyah" a book that explains how to use the Astrolabe in a new way, namely the Astrolabe tool called surfaces (Zurqalah). He was also the first to prove that the motion of the Sun's orbital tilt (almanac), when attributed to fixed stars, reached 12.05 seconds, then proved later that the correct number was 12.

Conclusion
The Abbasid caliphate stood after the collapse of the Umayyad caliphate, the name of the Abbasid caliphate is derived from one of the uncles of the Prophet named al-Abbas ibn Abd al-Muttalib ibn Hashim. With the establishment of the