What is Vedic astrology?

The word jyotisha comes from a Sanskrit root meaning light or heavenly body. The field covers astronomy, timekeeping and astrology together.

A jyotisha chart measures its twelve signs (rashis) from a point fixed against the stars. Western astrology measures from the March equinox. The gap between the two zero points, roughly 24 degrees today, is called the ayanamsa, and Indian authorities have not agreed on one value for it.

Two features stand out. The sky is also divided into 27 lunar mansions (nakshatras) of 13 degrees 20 minutes each. And the list of nine grahas includes Rahu and Ketu, the two points where the Moon's path crosses the Sun's.

An astrologer starts from the rising sign (lagna) and counts twelve houses (bhavas) from it. The Moon's nakshatra at birth sets the opening of the planetary periods (dashas), most often the system called Vimshottari, which are used to time stages of a life. Each sign is also cut into nine parts, the navamsa, a division found in all surviving Indian horoscopy and not attested in Greek sources.

Families in India have used these charts in naming children and in weighing marriage, business and moves. The sixth-century writer Varahamihira already composed separate treatises on marriage and on military campaigns.

The oldest surviving Indian text on the heavens is the Vedanga Jyotisha, attributed to Lagadha. It gives rules for locating the Sun, the Moon and the nakshatras so that a lunisolar calendar could be kept, and it works in a five-year cycle.

This text contains no horoscopes. According to the historian of Indian astral science Bill Mak, horoscopy was unknown in Vedic India, and the planetary lore and the zodiac of twelve equal signs are absent from it.

Sanskrit horoscopy is first seen in texts tied to the Yavanas, the Sanskrit name for Greeks. The Yavanajataka, whose title means roughly Birth Astrology of the Greeks, runs to about 2,270 verses and is attributed to Sphujidhvaja. Mak argues that a related work, the Vriddhayavanajataka of Minaraja, is probably older.

These books are adaptations. The Yavanajataka uses words of Greek origin such as drekkana, a third of a sign, from the Greek dekanos. It also brings in uniquely Indian material, including karma, Ayurvedic medicine, caste and nakshatra lore.

Varahamihira lived near Ujjain in the sixth century. His Brihat Jataka became, in David Pingree's assessment, the standard Indian work on birth charts, and he openly built on earlier writers. His Brihat Samhita deals with omens and other divination.

The Brihat Parashara Hora Shastra carries the name of the ancient sage Parashara. David Pingree, in the History of Indian Literature series edited by Jan Gonda, dated its first part to roughly 600 to 750 CE and described it as deeply indebted to Varahamihira. It was first printed in 1905.

Jyotisha remains active in Indian public life. After the University Grants Commission moved to introduce astrology as a university subject, India's Supreme Court in 2004 dismissed a petition against the plan.

The name Vedic is misleading for the horoscope itself. Mak writes that horoscopy has a Greco-Babylonian origin, and Pingree held a similar view. Other writers argue that jyotisha developed independently and only later met Greek ideas. The texts above do not show horoscopic methods in the Vedas.

The date of the Vedanga Jyotisha is contested. Subhash Kak reads an internal date of about 1350 BCE from its solstice positions, while Pingree, as reported on Wikipedia, placed it between 513 and 326 BCE.

The Yavanajataka was long dated to 269 or 270 CE, as a verse form of a lost prose translation made in 149 or 150 CE from a Greek book. That account appears in older reference works, including Pingree's. Mak argues from the manuscripts, including one found in Kathmandu in 2011, that the two dates rest on misreadings and that the text belongs between 550 and 600 CE. He also notes that the Brihat Jataka never names it or Sphujidhvaja, though its references to Yavana could mean either Greek-styled author. Pingree treated it as Varahamihira's main source.

The Parashara text is harder still to trace. The commentator Bhattotpala is reported to have heard of it without seeing it. Printed versions run from 25 to 97 chapters, and the editor of a 1944 edition is reported to have admitted altering what he found. Its authorship by a Vedic sage cannot be confirmed.