Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s5.71
Bhāratīya Jyotiḥśāstra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s5.71
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- English
v2.c12.s5.71.1
Let us now consider the question ofobservatories. It is evident that if the instruments of observation are permanently fixed they will be found more useful for observation. A building is specially erected for this purpose, and instruments are fixed in it and the work of taking observations is carried on there. Such a place is called ‘Vedhaśālā’ (or Observatory). It seems probable that in ancient times in our country such places might have been built under royal patronage and reserved for this purpose ; but we do not anywhere find their description. In some places, stone slabs are found on which lines showing directions are marked. It has been mentioned before, that Cintāmaṇi Dikṣit had such an arrangement for showing directions made at his place of residence in Sātārā. In 1884, the author had gone to Indore for taking part in the Sāyana pañcāṅga controversy. There he learnt that a place had been purposely set apart in the palace area, where lines showing directions have been marked, and astronomers, engaged by the Mahārājā Tukoji Rao, sometimes used to take observations there. The author met an astronomer from Bid who told him that some years ago some instruments had been constructed for the purpose of carrying on the work of taking continuous observations with the help of a party of astronomers maintained by the Moghul Government at Hyderabad ; but the work was later on discontinued. The author has seen astronomers at times taking observations by means of tube instruments.
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Such attempts on a moderate scale must have always been made in the past, but we have at present a reliable information about only one attempt of this kind made on a very big scale. It is as follows :—Jaya Simha (page 169) built five observatories. The author is giving below, an extract** from the introduction to his own works KSIZ MOHOMED by name. It will give a complete idia about his efforts :— “so incapable are human beings of comprehending the powers of the Almighty that Hipparchus can be said to be simply a rustic, and Ptolemy only a swallow. The theorems of Euclid are but an imperfect form of divine work. Similar by, thousands of people like Jamsedkasī and Nasīrtusī, have laboured in vain and became fatigued. The calculations made from works on astronomy like those of Sayad Gurganī and Khayānī, the Ākbarśāhi work of Inśil-al-Mulācand and astronomical works of Hindu writers as also those of European writers, do not agree with observed phenomena ; especially, the new moon’s appearance, risings and settings of planets, eclipses and conjunctions of planets do not agree with observation at all. When this fact was told to Emperor Mohomadsāh†, he asked him (i.e. Jaya Simha) to decide the matter. He erected at Delhi instruments like those erected by Mirzā Ulugbeg at Samar-kand . . . . .
v2.c12.s5.71.3
Jaya Simha found that his ideas about the correctness of results could not be realized by brass instruments, because the instruments were small, not convenient for showing minutes of arc, their axes shift their places and get worn out ; the centres of circular plates also shift their places and the planes of instruments get twisted. He thought these to be the reasons why the calculations of Hipparchus and Ptolemy did not tally with observed results. He, therefore, erected the Jaya Prakāś, the Rāma, and the Samrāt instruments which were perfectly stable and built in mortar and stone, whose semi-diameters were 18 cubits, and one grain (yava) in the circumference of which would represent 1 minute of arc. These were constructed and erected with due consideration of geometrical theory, the meridian, and latitude of the place and with careful measurements. They were so designed that it wold be possible to repair the defects caused by the sinking of circular planes, wearing out of axes, shifing of the central points, and irregular spacing of minute divisions. An observatory of this type was built at Delhi. Corrections to be applied to mean motions of planets, which never agreed with observation, were finally determined on the basis of observations taken with these instruments. In order to test the correctness of results of observations taken at the Delhi observatory, he erected similar observatories at Sawai, Jaipur, Mathura, Vāranasī and Ujjayinī.
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Observations taken at all these places tallied with one another. After seven years were spent in taking these observations, it was learnt that similar work was being done in Europe also. Hence, MANUEL, the priest and some other scholars were sent there and the planetary tables compiled 30 years ago and published in the name of LIEL*, were brought through them. The calculations made from them, however, did not agree with observations; it was found that there was an error of about 1/2 degree and some perceptible etror in the case of other planets. Hence, under the direction of the Emperor, a work was compiled containing formulae and mathematical processes for calculation, which were very precise and correct. Its calculation exactly tallies with observation. (The emperor’s name was given to the work as a mark of honour.)”