Discernment of the Truth of Astronomical Principles

Some scholars state that a month is determined by a single revolution of the Bhacakraoriginal: bhacakra; the "Wheel of Stars" or the entire zodiacal circle. However, the wise authors of the Saṃhitās traditional collections of knowledge or astrological treatises declare that the Sāvanaoriginal: sāvana; refers to "civil" or terrestrial time, measured from one sunrise to the next measurement is the standard, which is always established within the context of the celestial sphere, as joined with the scriptures. 20

By understanding the westward rotation of the celestial sphere and the simultaneous eastward speed of the planets, the wise have proclaimed the Sāvana day to be the period from one sunrise to the next. 21 For the Sun, this constitutes the seasonal month; for the other planets, there are various Sāvana measures. In this context, the Sun’s measure is called the "Terrestrial" or "Solar" day. 22 From New Moon to New Moon original: amāntād amāntaṃ; the "Amanta" system where the month ends on the New Moon is a month, and the Sauraoriginal: saura; solar time month proceeds in regular order. This is described as consisting of thirty Tithisoriginal: tithi; a lunar day, which is 1/30th of a lunar month or based on the Sun's movement through the degrees of the zodiac. 23

The Sāvana day is considered steady and is calculated based on the rotation of the celestial circle. It is said to consist of sixty Ghaṭikāsoriginal: ghaṭikā; a unit of time equal to 24 minutes. 24-25 A day and night for the Pitṛsoriginal: pitṝṇāṃ; the Ancestors or Manes is said to be equivalent to one human lunar month. For the Gods, a day and night is equivalent to one human year, but in a reversed manner implying their day is our six-month northward sun-path and their night is the six-month southward path. Thus, the day and night of the gods increase according to the movements of the celestial body. 26

One year, known as a Saṃvatsaraoriginal: saṃvatsara; a full Jovian or solar year, is defined by the Sun’s complete transit. In this cycle, the two Ayanasoriginal: ayana; the two halves of the year, the northern and southern transits occur for everyone, while the wheel of the stars rotates continuously in the sky. 27-28 It is not possible for those who do not know the scriptures to speak of these movements accurately at any time; the ancients described the rotations within the wheel of the stars. 29 Regarding the calculation of these periods, there are the "nodes" the points where planetary orbits cross the ecliptic and other factors which belong to the various Great Ages. When all these elements are combined through the primary calculation, they describe what is called "True Time" or "Clear Time." 30

The holy sages say that when time is calculated using improper methods, it is "Unclear Time." However, the revolutions of the planets that were described in the ancient scriptures by the Lord are beyond the reach of the ordinary senses. 31 The measurements of Solar, Lunar, and Civil time, the eastward motions of the planets, and the Great Ages—when all these are freed from doubt and completed, it is called "True Time" by the wise. 32 Those who know the celestial sphere speak of this precise calculation; it has been refined by the descendants of Brahma over five thousand five hundred (5,500) years. 33 This likely refers to the time elapsed since a specific epoch, such as the start of the Kali Yuga, relative to the author's era.

The sages say the measure of a Kalpaoriginal: kalpa; a "Day of Brahma," equaling 4.32 billion years is like a vast ocean of time. From the beginning of the creation's resolve, this has been the rule. 34 Because of the characteristics mentioned, this Time is divided into different types, such as "True" and "Mean," according to its results. 35

A Mahāyugaoriginal: mahāyuga; a "Great Age" consists of one thousandth of a Kalpa. Within a Mahāyuga, there are four smaller ages (Yugas). 36 These are the Kṛta, Tretā, Dvāpara, and Kali ages. In these, the practice of Dharma righteousness or cosmic order decreases in a regular sequence. 37 Thus, the four ages are said to follow the directions of the Vedas. The total length of a Mahāyuga is 4,320,000 solar years. 38

The individual ages, measured in solar years, are:

• Kṛta Yuga: 1,728,000 years
• Tretā Yuga: 1,296,000 years
• Dvāpara Yuga: 864,000 years