Manasara Series (I. A Dictionary of Hindu Architecture; II. Indian Architecture according to Manasara-Shilpashastra; III. Manasara on Architecture and Sculpture: Sanskrit Text; IV. Architecture of Manasara: Translation; V. Architecture of Manasara: Illustrations; VI. Hindu Architecture in India and Abroad; VII. An Encyclopaedia of Hindu Architecture) v2.c16.250

v2.c16.250

For the orientation of buildings it was necessary for the Indian architects to ascertain the right cardinal points. For this purpose the *Mānasāra* in agreement with all complete works on architecture including Vitruvius, makes use of a gnomon,³ obviously because the mechanism of the compass was not known to the ancient architects. For similar purpose the astronomical treatises⁴ also like the *Sūrya-siddhānta*, and the *Līlāvatī* and the *Siddhānta-śiromaṇi* of Bhāskarāchārya use the gnomon. The calculation of the shadow is the main object in this matter, and the gnomon is used simply to ascertain the shadow. The sun's rays falling on an object like the gnomon causes the shadow. So at first the obstructed light which gives rise to the shadow, must naturally be taken from the sun. But the sun's light is uncertain and cannot be adjusted according to the requirements of the scientific and advanced study. It is, therefore, not difficult to believe that the later astronomers easily found out some artificial and adjustable light to replace the natural and unadjustable light from the sun. In the *Mānasāra* only the sun's light is made use of, while in the *Sūrya-siddhānta* and other astronomical works lamp light was used in order to measure the shadow. These latter works also followed an improved method in ascertaining the level whereupon the gnomon was erected in order to calculate the movement of the shadow accurately. The methods followed in the *Mānasāra* are antiquated. It seems, therefore, that the *Sūrya-siddhānta* and other astronomical works must come after the *Mānasāra*.