Vedanga Jyotisha: the early text
Vedanga Jyotisha is one of the earliest surviving Jyotish texts. It is one of the six Vedangas, the auxiliary disciplines of the Vedas, and it is concerned with the timing of sacrifices.
What it is
The text describes the motion of the Sun and Moon, the lunar and solar years and the timing of rituals. It is traditionally attributed to Lagadha, and its date is debated, with many scholars placing it in the first millennium BCE.
How it is worked out or read
The text is a useful reference for the early calendar and the idea of nakshatras as a sequence, which later Jyotish built on. It does not give the planetary and house systems of later texts.
Where it appears on this site
The early calendar ideas are discussed in the history article.
What the text is for
Vedanga Jyotisha belongs to the group of six Vedangas, the auxiliary disciplines that help in the correct recitation and performance of the Vedic texts. Its purpose is practical: to fix the timing of the sacrifices by the positions of the Sun and Moon, and to reconcile the lunar and solar years. The text is short, and it is written in a compressed style that later commentators had to unpack.
Its surviving versions are generally dated by scholars to a period in the first millennium before the Common Era, although the exact date is debated and the text may have been compiled over time.
What it shows about early Jyotish
The text shows that early Indian observers had already identified the nakshatras as a sequence of lunar positions, and that they were using a five-year cycle to bring the lunar and solar years into step. These ideas are the foundations on which the later calendar and the later Jyotish were built. A reader who studies the text sees the origin of the practical concern with time that runs through the whole tradition.
Two recensions
The text survives in two main versions: one attached to the Rigveda, of 36 verses, and one attached to the Yajurveda, of 43 or 44 verses, which overlap a great deal. Tradition names Lagadha as the author or teacher behind it. A related later text, the Atharva Jyotisha, deals mainly with muhurta and the qualities of times.
The five-year yuga
The text's calendar uses a cycle of five years, called a yuga, of 1,830 days. In that period it counts 62 synodic months and 67 sidereal months of the Moon, which allowed two intercalary months to be inserted to keep the lunar months in step with the solar year. The scheme was approximate, and later astronomers replaced it with more accurate models.
The solstice clue
The text places the winter solstice at the beginning of the nakshatra Shravishtha, now called Dhanishta. Because precession moves the solstice slowly against the stars, some scholars have used this statement to estimate the period of the observations it records, arriving at dates in the second millennium BCE. Such estimates depend on assumptions about the observations and remain debated.