The 12 rashis and the sidereal zodiac

Two zodiacs, one sky

A rashi is a 30° slice of the ecliptic, the path the Sun appears to follow through the year. Twelve slices make 360°. Both Western and Vedic astrology use these twelve names, but they start counting from different places. The Western (tropical) zodiac starts 0° Aries at the spring equinox, the point where the Sun crosses the celestial equator going north. The Vedic (sidereal) zodiac starts 0° Mesha at a fixed point among the stars, traditionally opposite the star Chitra (Spica).

Those two starting points were the same about 1,700 years ago. Because the Earth's axis slowly wobbles (precession), the equinox drifts backwards through the stars by about one degree every 72 years. Today the gap is close to 24°. That gap is the ayanamsa.

The ayanamsa

Sidereal longitude = tropical longitude − ayanamsa. Several ayanamsa values are in use because astronomers and astrologers disagree on exactly where the fixed starting point is. Lahiri (Chitrapaksha), adopted by the Indian government's calendar reform committee in 1955, is the default in most Indian almanacs and in LifeAstroAPI; Raman, Krishnamurti (KP) and others differ from it by up to a degree. On 15 January 2027 the Lahiri ayanamsa is about 24.2°. The practical effect: a Sun at 5° tropical Leo is at about 11° sidereal Karka. This is why so many people change sign when they first see a Vedic chart: anyone born in the first three weeks of a Western sign usually moves back one rashi.

The twelve rashis

Each rashi has a ruling planet (lord), an element and a modality. The lords repeat in a mirror pattern around the Sun and Moon: Mesha and Vrishchika belong to Mangal, Vrishabha and Tula to Shukra, Mithuna and Kanya to Budha, Dhanu and Meena to Guru, Makara and Kumbha to Shani; Simha is the Sun's and Karka the Moon's.

The elements run fire, earth, air, water and repeat three times. The modalities run movable (chara), fixed (sthira), dual (dvisvabhava) and repeat four times. So each sign is a unique pair: Mesha is movable fire, Vrishabha fixed earth, Mithuna dual air, and so on. Muhurat uses the modality (fixed signs rising for lasting works), matching uses the lord and element, and the dignity of every planet is read against the sign it sits in: a planet in its own sign or its exaltation sign is strong, in its debilitation sign weak.

Exaltation and debilitation

Each of the seven classical planets has one sign where it is exalted (uchcha) and the opposite sign where it is debilitated (neecha): the Sun in Mesha / Tula, the Moon in Vrishabha / Vrishchika, Mars in Makara / Karka, Mercury in Kanya / Meena, Jupiter in Karka / Makara, Venus in Meena / Kanya, Saturn in Tula / Mesha. Each has an exact degree of deepest exaltation, listed on every rashi page.

Moon sign, lagna, Sun sign: which one is "your sign"?

A Western horoscope column means your Sun sign. A Hindi rashifal means your Moon sign(chandra rashi): the sign the Moon occupied at birth, which also fixes your janma nakshatra. The lagna (ascendant) is the sign rising in the east at the moment of birth; it changes every two hours, which is why the birth time matters, and it sets the first house of the kundli. Jyotish reads the lagna chart first, the Moon chart second, and uses the Sun sign least. Each rashi page carries the authored reading for that sign as the lagna.

Rashi and nakshatra together

A rashi holds two and a quarter nakshatras (nine padas). Knowing the Moon's rashi tells you the broad temperament; the nakshatra inside it refines it and sets the dasha. Mesha, for example, contains Ashwini, Bharani and the first pada of Krittika. The nakshatra chaptercovers that layer.

Finding your rashi

You need the birth date, time and place. Compute the Moon's sidereal longitude and divide by 30: 0 is Mesha, 11 is Meena. LifeAstroAPI returns the Moon sign, lagna and every planet's sign in one call (/v1/chart/planets, sign_index per planet), using Lahiri unless you pass anotherayanamsa.