The Confusion: "I'm Aries, or Am I Pisces?"
"My Western horoscope says I'm Aries, but when I look up my Jyotish chart it says Meena (Pisces). Which one is right?" The answer: both are right. They simply measure different things.
Western astrology assigns your sign based on the Sun's position on the day you were born, measured relative to the vernal equinox. Tamil and Vedic astrology assign your sign based on the Moon's position, measured relative to the actual fixed stars. The two reference lines are not the same, and they keep drifting further apart.
Tropical vs Sidereal Zodiac
The tropical zodiac is anchored to the seasons: 0° Aries begins at the vernal equinox, around March 21 in the Northern Hemisphere. This system was standardised by Ptolemy in the 2nd century and forms the basis of Western astrology.
The sidereal zodiac is anchored to the stars: 0° Mesha (Aries) is defined by a fixed star, in the Lahiri system, the star Spica (Chitra) is locked to exactly 180°. The 12 signs and 27 nakshatras are laid out on this fixed framework.
The gap exists because of precession, Earth's rotational axis wobbles like a spinning top, causing the equinox point to shift relative to the stars. A full cycle takes about 26,000 years.
Ayanamsa, The Drift Between the Two Systems
The angle by which the equinox point has shifted from the sidereal zero point is called ayanamsa (Sanskrit: ayana = movement, amsha = portion). It grows by approximately 50.3 arcseconds per year.
About 1,700 years ago the two zodiacs were aligned, tropical and sidereal 0° Aries were the same point. Today the ayanamsa is approximately 24°, meaning the tropical zodiac has moved nearly a full sign (30°) ahead of the sidereal one.
Worked example
Example: what ayanamsa does to a sign
A person born with the Sun at 15° tropical Taurus.
- Tropical longitude
- 45° (15° into Taurus)
- Ayanamsa (Lahiri, 2026)
- approx. 24° 08′
- Sidereal longitude
- 45° − 24° 08′ ≈ 20° 52′
Western astrology: sign is Taurus.
20° 52′ falls in Mesha (Aries), 0°–30°.
The same person is Taurus in Western astrology but Aries (Mesha) in Vedic astrology.
Practical Impact: What Does Your Sign Shift To?
With an ayanamsa of about 24°, most people shift back by one sign in the sidereal system. The table below shows what your Western Sun sign typically corresponds to in Jyotish, but remember, Jyotish uses the Moon's position, so your actual janma rashi requires a precise calculation with birth time and place.
| Western Sign | Tropical Range | Typical Jyotish Rashi |
|---|---|---|
| Aries (Mar 21–Apr 19) | 0°–30° | Meena (Pisces) |
| Taurus (Apr 20–May 20) | 30°–60° | Mesha (Aries) |
| Gemini (May 21–Jun 20) | 60°–90° | Rishabha (Taurus) |
| Cancer (Jun 21–Jul 22) | 90°–120° | Mithuna (Gemini) |
| Leo (Jul 23–Aug 22) | 120°–150° | Kataka (Cancer) |
| Virgo (Aug 23–Sep 22) | 150°–180° | Simha (Leo) |
| Libra (Sep 23–Oct 22) | 180°–210° | Kanya (Virgo) |
| Scorpio (Oct 23–Nov 21) | 210°–240° | Thula (Libra) |
| Sagittarius (Nov 22–Dec 21) | 240°–270° | Vrischika (Scorpio) |
| Capricorn (Dec 22–Jan 19) | 270°–300° | Dhanus (Sagittarius) |
| Aquarius (Jan 20–Feb 18) | 300°–330° | Makara (Capricorn) |
| Pisces (Feb 19–Mar 20) | 330°–360° | Kumbha (Aquarius) |
Which One Is "Right"?
Neither is wrong. They measure different things. The tropical system tracks seasons; the sidereal system tracks fixed stars. Different tools for different purposes.
Western astrology focuses on the Sun's cycle and the march of the seasons, the tropical zodiac is a seasonal tool. Vedic astrology focuses on the Moon's position among the stars, the sidereal zodiac is a star map.
This site uses the sidereal system because panchangam is a sidereal system. Tithi, nakshatra, yoga, and karana all require sidereal calculations (tithi is itself ayanamsa-independent, but the other four limbs are sidereal). When we show rashi, we show the sidereal Moon rashi.
The 12 Rashis, The Tamil Zodiac
The sidereal zodiac has the same 12 signs as the Western one, but shifted by about 24°. Each sign spans 30° and has a ruling planet.
| No. | Tamil | Sanskrit | Western Name | Ruler |
|---|---|---|---|---|
| 1 | மேஷம் (Mesham) | Mesha | Aries | Mars |
| 2 | ரிஷபம் (Rishabam) | Rishabha | Taurus | Venus |
| 3 | மிதுனம் (Mithunam) | Mithuna | Gemini | Mercury |
| 4 | கடகம் (Kadakam) | Kataka | Cancer | Moon |
| 5 | சிம்மம் (Simmam) | Simha | Leo | Sun |
| 6 | கன்னி (Kanni) | Kanya | Virgo | Mercury |
| 7 | துலாம் (Thulaam) | Thula | Libra | Venus |
| 8 | விருச்சிகம் (Viruchigam) | Vrischika | Scorpio | Mars |
| 9 | தனுசு (Dhanusu) | Dhanus | Sagittarius | Jupiter |
| 10 | மகரம் (Makaram) | Makara | Capricorn | Saturn |
| 11 | கும்பம் (Kumbam) | Kumbha | Aquarius | Saturn |
| 12 | மீனம் (Meenam) | Meena | Pisces | Jupiter |
Rashi from Nakshatra, 2.25 per Sign
In Jyotish, your Moon sign (janma rashi) is not determined by the Sun's position as in Western astrology. It is determined by the Moon's position, specifically, by the nakshatra and pada (quarter) the Moon occupies at your birth.
The 27 nakshatras have 108 padas in total (27 × 4). The 12 rashis have 108 quarters in total (12 × 9). So each rashi contains exactly 9 padas, equivalent to 2.25 nakshatras. Mesha, for example, contains all of Ashwini (4 padas), all of Bharani (4 padas), and the first pada of Krittikai.
- Mesha (Aries): Ashwini (1–4), Bharani (1–4), Krittikai (1)
- Rishabha (Taurus): Krittikai (2–4), Rohini (1–4), Mrigashirsham (1–2)
- Mithuna (Gemini): Mrigashirsham (3–4), Thiruvadhirai (1–4), Punarpoosam (1–3)
- Kataka (Cancer): Punarpoosam (4), Poosam (1–4), Ayilyam (1–4)
- Simha (Leo): Magam (1–4), Pooram (1–4), Uthiram (1–2)
- Kanya (Virgo): Uthiram (3–4), Astham (1–4), Chithirai (1–2)
- Thula (Libra): Chithirai (3–4), Swathi (1–4), Visakam (1–3)
- Vrischika (Scorpio): Visakam (4), Anusham (1–4), Kettai (1–4)
- Dhanus (Sagittarius): Moolam (1–4), Pooradam (1–4), Uthiradam (1–2)
- Makara (Capricorn): Uthiradam (3–4), Thiruvonam (1–4), Avittam (1–2)
- Kumbha (Aquarius): Avittam (3–4), Sadhayam (1–4), Poorattadhi (1–3)
- Meena (Pisces): Poorattadhi (4), Uthirattadhi (1–4), Revathi (1–4)