Astroyana research · ayanamsa
Does astrology even agree with itself?
Sidereal astrology requires a starting point for the zodiac, called the ayanamsa, and astrologers do not all use the same one. We recomputed 50,000 charts under the four systems in common use (Lahiri, KP, Raman and True-Chitra) and checked how often the basic verdicts change. Three of the four agree closely. The older Raman system is the outlier, which helps explain why two astrologers can produce different charts.
10.8%
of charts: the four systems don't all agree on your nakshatra
18.5%
have some disagreement on Moon sign, nakshatra or ascendant
10.8%
Raman differs from Lahiri on the nakshatra
5.2%
have a Manglik verdict that depends on the system
Most systems agree; Raman is the outlier
Lahiri, KP and True-Chitra sit within a few arc-minutes of each other, so they almost never disagree on the nakshatra. Raman sits roughly a degree away, which is enough to push the Moon across a nakshatra boundary about one time in nine.
Why a fraction of a degree matters
A nakshatra is only 13°20′ wide and a sign is 30°, so most placements sit comfortably inside one. Near a boundary, however, a small ayanamsa difference can move the Moon into the next slot. That can change the nakshatra, dasha sequence and any verdict that depends on them. The ascendant, which moves about one degree every four minutes, is the most sensitive.
What it means for your chart
The disagreement is real but limited. The mainstream ayanamsas agree in most cases. Astroyana uses Lahiri, the official Indian standard, across every calculator and report so your nakshatra, dasha and doshas stay consistent from page to page. If a reading surprises you, check the ayanamsa first.
More on this in which ayanamsa is correct and why astrology sites show different charts.
Methodology
Synthetic study — no real user data. Birth moments are sampled uniformly across the date range and clock; birthplaces are sampled across major Indian cities weighted by population. Percentages are the mathematical base rate per birth moment, not a population census. Reproducible from the committed script with the fixed seed. Each chart is recomputed under Lahiri, KP, Raman and True-Chitra; the 'ayanamsa' field below is the Lahiri baseline the others are compared against.
- Sample size
- 50,000 charts
- Birth date range
- 1950-01-01 to 2009-12-31
- Timezone
- IST (UTC+5:30)
- Birth hour
- uniform
- Locations
- population-weighted across 25 major Indian cities
- Ayanamsa
- lahiri
- Nodes
- mean
- House system
- whole_sign
- Seed
- 20260603
FAQ
Why do two astrologers give me different charts?
Often because they use a slightly different starting point for the zodiac, known as the ayanamsa. Across 50,000 charts, switching system changed the nakshatra in up to 10.8% of cases and the Manglik verdict in 5.2%.
Which ayanamsa is correct?
Lahiri (Chitrapaksha) is the Indian government standard and what most Vedic software uses; True-Chitra is a refinement of it, and KP is very close. Raman is an older alternative about one degree away, so it produces the most disagreements.
Which ayanamsa does Astroyana use?
Astroyana uses Lahiri, the official Indian standard, across every calculator and report so results remain consistent.
Free to cite with attribution to Astroyana. Figures are the mathematical base rate per birth moment from a synthetic sample, computed with our Swiss-Ephemeris (Lahiri) engine — not a survey of real people, and not a claim about anyone’s life.