Vedic astrology: an introduction to Jyotish

What “Jyotish” means

Jyotish comes from the Sanskrit jyoti, light, and is often translated as “the science of light”. It is listed among the six Vedangas, the auxiliary disciplines connected with the Vedas, where it originally served calendar-keeping and the timing of rituals. Horoscopic astrology developed within it over many centuries, with classical texts such as the Brihat Parashara Hora Shastra and Varahamihira’s Brihat Jataka still widely referenced.

Sidereal vs tropical zodiac

Both zodiacs divide the sky into twelve 30° signs with the same names. They differ in where they start:

• Tropical zodiac (most Western astrology) starts 0° Aries at the March equinox, so it is fixed to the seasons.
• Sidereal zodiac (Vedic astrology) anchors the signs to the background stars.

Because Earth’s axis slowly wobbles (precession of the equinoxes), the equinox point drifts backwards against the stars by about 1° every 72 years. The two zodiacs coincided roughly 1,700 to 1,800 years ago and are now about 24° apart. That is why someone who is a Western Leo is often a Vedic Cancer.

Ayanamsa

The ayanamsa is the angle between the tropical and sidereal starting points. To get a sidereal position, you subtract the ayanamsa from the tropical longitude. Several ayanamsas exist; the Lahiri (Chitrapaksha) ayanamsa, which places the star Spica (Chitra) at 0° Libra, is the most widely used in India and is the default at AstroVeda AI.

The nine grahas

Graha literally means “one that grasps”. The nine grahas are the seven visible bodies plus Rahu and Ketu, the points where the Moon’s orbit crosses the Sun’s apparent path (the points associated with eclipses). Rahu and Ketu are always exactly opposite each other and usually move backwards through the zodiac.

Outer planets such as Uranus and Neptune are not part of classical Jyotish and are not used in AstroVeda AI interpretations.

The twelve bhavas (houses)

The houses describe areas of life. They are counted from the Ascendant (Lagna). In the whole sign system, which we use, the entire rising sign is the 1st house, the next sign is the 2nd house and so on. Each house has a traditional name and a cluster of meanings:

Our guide to reading a Vedic birth chart shows how houses, signs and planets combine.

Signs and Nakshatras

The twelve signs, or Rashis, each span 30°. Overlaid on them are the 27 Nakshatras, lunar mansions of 13°20′ each. The sign the Moon occupies is your Rashi; the Nakshatra the Moon occupies is your birth star, and it drives the dasha calculation.

Dashas: how Vedic astrology handles timing

A distinctive feature of Jyotish is the dasha system, a sequence of planetary periods. The most widely used is Vimshottari (“120”), whose nine periods add up to 120 years:

Your sequence starts with the lord of the Nakshatra the Moon occupied at birth, and the balance of that first period depends on how far the Moon had travelled through the Nakshatra. Each Mahadasha is subdivided into nine Antardashas in the same order. Astrologers read a period through the condition of its ruling planet in your chart.