since the ancient times, has been the best known and the most referred astronomical text in the Indian tradition. The fourteen chapters of the Surya Siddhanta are as follows, per the much cited Burgess translation: The methods for computing time using the shadow cast by a gnomon are discussed in both Chapters 3 and 13. Description of Time The author of Surya Siddhanta defines time as of two types: the first which is continuous and endless, destroys all animate and inanimate objects and second is time which can be known. This latter type is further defined as having two types: the first is Murta (Measureable) and Amurta (immeasureable because it is too small or too big). The time Amurta is a time that begins with an infinitesimal portion of time (Truti) and Murta is a time that begins with 4-second time pulses called Prana as described in the table below. The further description of Amurta time is found in Puranas where as Surya Siddhanta sticks with measurable time. The text measures a savana day from sunrise to sunrise. Thirty of these savana days make a savana month. A solar (saura) month starts with the entrance of the sun into a zodiac sign, thus twelve months make a year. North pole star and South pole star Surya Siddhanta asserts that there are two pole stars, one each at north and south celestial pole. Surya Siddhanta chapter 12 verse 43 description is as following: मेरोरुभयतो मध्ये ध्रुवतारे नभ:स्थिते। निरक्षदेशसंस्थानामुभये क्षितिजाश्रिये॥१२:४३॥ This translates as "On both sides of the Meru (i.e. the north and south poles of the earth) the two polar stars are situated in the heaven at their zenith. These two stars are in the horizon of the cities situated on the equinoctial regions". The Sine table The Surya Siddhanta provides methods of calculating the sine values in chapter 2. It divides the quadrant of a circle with radius 3438 into 24 equal segments or sines as described in the table. In modern-day terms, each of these 24 segments has angle of 3.75°. The 1st order difference is the value by which each successive sine increases from the previous and similarly the 2nd order difference is the increment in the 1st order difference values. Burgess says, it is remarkable to see that the 2nd order differences increase as the sines and each, in fact, is about 1/225th part of the corresponding