Vedic Astrology (Jyotisha)

Jyotisha ("the science of light") shares ancient Babylonian roots with Western astrology but diverged on three foundational choices: it uses the sidereal zodiac (anchored to the actual fixed stars) rather than the tropical zodiac (anchored to the seasons); it treats the Moon sign (Chandra Rashi) as the chart's primary emotional/psychological anchor rather than the Sun sign; and it adds Rahu and Ketu (the lunar nodes — mathematical points, not physical bodies, marking where the Moon's orbit crosses the ecliptic) in place of the outer planets Uranus, Neptune, and Pluto. Because the stars have slowly drifted relative to the seasons over roughly two millennia (precession), the tropical and sidereal zodiacs no longer line up — the gap between them, the ayanamsa, is currently about 24 degrees, nearly a full sign, which is why most people's Vedic Sun sign runs one sign "earlier" than their Western one. The 9 grahas ("seizers" — usually translated "planets," though two have no physical body at all: Rahu and Ketu) sit within the 12 Rashis (the same 12 signs conceptually as Western astrology, with Sanskrit names, each roughly one sign behind its tropical counterpart). The system's layer with no real Western equivalent is the 27 Nakshatras — lunar mansions, each a 13°20' slice of the zodiac the Moon passes through roughly one per day across its ~27-day orbit, giving a far more specific "neighborhood" than the 12 broad Rashis; a person's Moon Nakshatra at birth is what determines which planet opens their Vimshottari Dasha sequence. The 12 Bhavas (houses) are conceptually close to Western houses, most often read as whole-sign (the entire sign containing the Ascendant becomes the 1st house, and so on, rather than dividing houses by exact degree). The Vimshottari Dasha is a 120-year cycle divided among the 9 grahas, each ruling a fixed block of years (Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17 — totaling exactly 120), running in fixed order and repeating past age 120; which period a person is born into, and how far into it, is determined entirely by their Moon's exact Nakshatra degree at birth. Each major Dasha further subdivides into 9 Antardasha sub-periods, proportional to that graha's own length — a 20-year Venus Dasha still contains shorter Saturn and Sun sub-periods within it. Glossary: Navamsa/D9 (a secondary harmonic chart used specifically for marriage and inner dharma) and Yoga (a specific planetary combination read to produce a particular life theme — distinct from the meditative practice of the same name).