The Surya Siddhanta

original: "सूर्यसिद्धान्त:" — The "Sun Treatise," the foundational text of Indian astronomy.

That is called a day of the gods. And so, between the gods and the demons, there is a distinction in the day and night due to their inversion The gods are said to dwell at the North Pole and the demons at the South Pole; thus, when it is day for one, it is night for the other, but not in the actual measurement of time. Since their full day-and-night cycle is identical, the measurement of the day-and-night of the demons is implicitly stated by the description of the day-and-night of the gods. To explain the Great Age, the author defines a "divine year" in another way to highlight its specific nature, even though it is easy to understand. "Sixty of those," he says. Sixty divine day-and-night cycles make a divine season. Multiplied by the six seasons of the year, this constitutes a divine year, also pertaining to the demons original: "दैत्य" (Daitya). The word "and" implies the inclusion of both. The word "only" original: "एव" (eva) is used to dispel the foolish doubt that there might be a difference in their years because of the difference in their days and nights. || 14 || Now, wishing to describe the measurement of a Kalpa A "Kalpa" is an immense cosmic period equal to a day of Brahma, he first describes the measurement of the Great Age and its components in two verses:

Twelve thousand of those divine years constitute a Four-Age Cycle Chaturyuga: a cycle of four cosmic ages. This refers to the Great Age Mahayuga, which is the sum or combination of the four ages known as Krita, Treta, Dvapara, and Kali. The word "four" is used specifically to indicate this; otherwise, simply saying "Age" Yuga would be redundant. This has been stated by those expert in measurements. Now, he provides the specific number according to solar measurement. "In the count of solar years," he says. That Four-Age Cycle, which was said to consist of twelve thousand years in the measurement of the gods and demons, is a Great Age including the "twilight" Sandhya and "twilight-portion" Sandhyamsha. Each stage of the age is joined at its beginning and end by a twilight and a twilight-portion respectively; these are included within the age, not separate from it. And such is the solar—