:::note
**TL;DR**
- Each nakshatra spans 13°20 (800 arcminutes), each pada 3°20 (200 arcminutes). A 6 arcminute Moon drift can cross a pada boundary.
- A pada flip changes the navamsa sign, which can swing Bhakoot and Nadi koota points and reverse the marriage verdict.
- Three drift sources matter in any API call: ayanamsa version, birth time precision, and location coordinates.
- Build kundli matching with verified Moon nakshatra and pada output. [Vedic Astrology API](/products/vedic-astrology-api "Vedic Astrology API with kundli, dasha, panchang, KP, and Gun Milan").
:::

Two kundli matching apps run the same boy and girl through Ashtakoota Gun Milan and return different verdicts. One returns 24 out of 36 with a clean recommendation. The other returns 18 out of 36 with a Bhakoot dosha warning. The bride and groom are the same. The birth records are the same. The disagreement comes down to a single number: where the Moon sits inside its nakshatra, measured in arcminutes. This post walks through how a 6 arcminute Moon position drift can cross a pada boundary, change the navamsa sign, and break the Gun Milan score that a matrimonial product reports to a family. Then it shows how to call the Vedic kundli endpoint with enough precision to remove the drift.

## Why 6 arcminutes can flip a Vedic marriage match

:::stat 6 arcmin
**Smallest Moon longitude drift that can cross a pada boundary** when the Moon sits within 6 arcminutes of any 3°20 boundary inside a nakshatra. A pada flip changes the navamsa sign and can swing Gun Milan by 5 to 10 points.
:::

A nakshatra pada is a quarter of one nakshatra. Each nakshatra is 13°20 of zodiacal longitude, which is 800 arcminutes; each pada is 3°20, or 200 arcminutes. Pada determines the Navamsa (D9) sign for any planet, and the Moon pada drives Bhakoot and Nadi koota inside Ashtakoota Gun Milan. When the Moon sits inside the last 6 arcminutes of a pada, any small calculation drift can push it across the boundary into the next pada and change the D9 sign. Bhakoot is scored 0 or 7 out of 7 depending on the Moon sign distance between partners; Nadi is scored 0 or 8. A pada flip near a sign boundary can move the Moon to a different rashi, flipping both kootas at once. That is up to 15 of the 36 Gun Milan points moving on a 6 arcminute drift.

Ready to build verified kundli matching? [Vedic Astrology API](/products/vedic-astrology-api "Vedic Astrology API with kundli, dasha, panchang, KP, and Gun Milan") returns Moon longitude, nakshatra, and pada with precision suited for matrimonial matching. [See pricing](/pricing "RoxyAPI pricing and plan tiers").

## How nakshatra padas map to navamsa signs

Pada to navamsa mapping follows a fixed rule per element. For movable signs (Aries, Cancer, Libra, Capricorn) the nine navamsas of the rashi start from the rashi itself. For fixed signs they start from the ninth rashi from the sign; for dual signs from the fifth. Ashlesha is the ninth nakshatra and sits entirely inside Cancer, from 16°40 to 30°00 sidereal. Cancer is movable, so the Cancer navamsas start from Cancer at 0°00. Each navamsa is 3°20 of longitude. The four padas of Ashlesha therefore map to navamsa signs Sagittarius, Capricorn, Aquarius, and Pisces. A Moon at 19°58 Cancer sits in Pada 1, navamsa Sagittarius. A Moon at 20°02 Cancer sits in Pada 2, navamsa Capricorn. The boundary is 4 arcminutes apart.

| Ashlesha pada | Sidereal range (Cancer) | Pada lord | Navamsa sign | Sample Moon |
|---|---|---|---|---|
| Pada 1 | 16°40 to 20°00 | Jupiter | Sagittarius | 19°58 Cancer |
| Pada 2 | 20°00 to 23°20 | Saturn | Capricorn | 20°02 Cancer |
| Pada 3 | 23°20 to 26°40 | Saturn | Aquarius | 24°00 Cancer |
| Pada 4 | 26°40 to 30°00 | Jupiter | Pisces | 28°00 Cancer |

The two sample Moons are 4 arcminutes apart, sit in the same nakshatra, and produce different navamsa signs. Bhakoot uses Moon rashi, but a navamsa change can still alter dasha balance and divisional house lords used in the wider matching report.

## Where pada drift comes from in your API call

Three independent sources can shift the Moon by enough arcminutes to flip a pada. Knowing each source lets you instrument an API integration so the precision floor is known and bounded.

1. **Ayanamsa version.** Lahiri, Raman, and KP Newcomb sit roughly 1° apart in 2026. That is 60 arcminutes. Switching ayanamsa near any pada boundary will flip the pada. Lahiri is the official Indian government ayanamsa and the default in most matrimonial software; Raman is older and trails Lahiri by about 7 arcminutes; KP Newcomb leads Lahiri by about 6 arcminutes. The Moon at 19°55 Cancer sidereal under Lahiri is at 20°02 under KP Newcomb, which is on the other side of the pada boundary.

2. **Birth time precision.** The Moon moves through roughly 13° of longitude per day, which is 32.5 arcminutes per hour or 0.54 arcminutes per minute of clock time. Recording a birth time as 14:00 when the actual time was 14:11 introduces a 6 arcminute Moon drift. Round to the nearest five minutes and you build in up to 1.4 arcminutes of slop on the Moon alone. The Lagna moves about 1° every 4 minutes, which is 15 arcminutes per minute, so birth time uncertainty hits the Ascendant ten times harder than it hits the Moon.

3. **Location precision.** Latitude and longitude only matter for Lagna and house cusps in the Vedic Moon-pada calculation, but if a chart endpoint reads the wrong city centroid (Mumbai versus a suburb 30 km away) the local mean time offset can change by 1 to 2 minutes, which propagates to the Moon as 0.5 to 1 arcminutes. Coordinates from a verified geocoder remove this entirely.

:::warning Ayanamsa version is the dominant drift source
Switching ayanamsa between Lahiri, Raman, and KP Newcomb shifts every sidereal longitude by about 60 arcminutes. That alone will flip multiple padas and can change the recommendation in any kundli matching report. Pin the ayanamsa explicitly in your integration and document the choice. Lahiri is the matrimonial default in India.
:::

## How to verify pada output across two API providers

Cross-checking the Moon nakshatra and pada between two independent providers takes four numbers per chart: Moon sidereal longitude in degrees, nakshatra name, pada (1 to 4), and navamsa sign. If all four agree, the matching report is reproducible. If the longitudes agree to within 0.05° but pada or navamsa disagree, one provider is using a different ayanamsa or a different pada-to-navamsa rule. If the longitudes disagree by more than 0.1°, the time inputs or the ayanamsa differ. Build a verification harness that runs ten test charts with Moon positions deliberately placed within 30 arcminutes of pada boundaries, then run the same inputs against both providers. Boundary cases are where disagreements surface; charts with the Moon mid-pada agree across almost any reasonable provider. The RoxyAPI Vedic kundli response returns `meta.Moon.longitude` (sidereal degrees), `meta.Moon.nakshatra.name`, `meta.Moon.nakshatra.pada`, and `meta.Moon.rashi`. Verification is a four-field comparison.

| Field | Compare | Acceptable drift |
|---|---|---|
| `meta.Moon.longitude` | Decimal degrees | Under 0.02° (1.2 arcminutes) |
| `meta.Moon.nakshatra.name` | String match | Must match exactly |
| `meta.Moon.nakshatra.pada` | Integer 1 to 4 | Must match exactly |
| `meta.Moon.rashi` | Sign name | Must match exactly |

## How to call the nakshatra endpoint correctly

Every Vedic kundli endpoint requires latitude, longitude, and timezone. Never ask users to type coordinates. Call `GET /location/search` first to geocode the birth city, then feed the result into `POST /vedic-astrology/birth-chart`. The IANA timezone string from the city result resolves to the DST-correct offset for the birth date on the server. Read more about the 27 lunar mansions in the [nakshatras complete guide](/blogs/nakshatras-27-lunar-mansions-vedic-astrology-complete-guide "27 nakshatras with ruling planets and characteristics"), and the ayanamsa choices in the [Lahiri, Raman, KP comparison](/blogs/ayanamsa-lahiri-raman-kp-developers "ayanamsa version differences and developer impact"). For accuracy methodology and the gold-standard test set, see the [methodology page](/methodology "test methodology and ephemeris validation").

:::tabs
### curl
```bash
# Step 1: geocode the birth city
curl -s "https://roxyapi.com/api/v2/location/search?q=Mumbai" \
  -H "X-API-Key: $ROXY_API_KEY" | jq '.cities[0]'

# Step 2: birth chart with Moon nakshatra and pada
curl -s "https://roxyapi.com/api/v2/vedic-astrology/birth-chart" \
  -H "X-API-Key: $ROXY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "date": "1992-08-15",
    "time": "14:11:00",
    "latitude": 19.0760,
    "longitude": 72.8777,
    "timezone": "Asia/Kolkata"
  }' | jq '.meta.Moon'
```

### TypeScript
```typescript
import { Roxy } from '@roxyapi/sdk';

const roxy = new Roxy({ apiKey: process.env.ROXY_API_KEY });

const city = await roxy.location.searchCities({ q: 'Mumbai' });
const place = city.cities[0];

const chart = await roxy.vedicAstrology.generateBirthChart({
  date: '1992-08-15',
  time: '14:11:00',
  latitude: place.latitude,
  longitude: place.longitude,
  timezone: place.timezone,
});

console.log(chart.meta.Moon.nakshatra.name, chart.meta.Moon.nakshatra.pada);
```

### Python
```python
from roxy import Roxy
import os

roxy = Roxy(api_key=os.environ["ROXY_API_KEY"])

city = roxy.location.search_cities(q="Mumbai")
place = city.cities[0]

chart = roxy.vedic_astrology.generate_birth_chart(
    date="1992-08-15",
    time="14:11:00",
    latitude=place.latitude,
    longitude=place.longitude,
    timezone=place.timezone,
)

moon = chart.meta["Moon"]
print(moon.nakshatra.name, moon.nakshatra.pada)
```
:::

For the Gun Milan side of matching, post both partners to [`POST /vedic-astrology/compatibility`](/api-reference#tag/vedic-astrology/POST/vedic-astrology/compatibility "Ashtakoota Gun Milan with 36-point breakdown and dosha cancellations"). The response returns `total`, `maxScore` (36), `percentage`, `isCompatible`, the eight koota `breakdown` entries, plus `doshas` and `doshaCancellations`. Bhakoot and Nadi appear in `breakdown` with their scores and in `doshas` if uncancelled.

## FAQ

**What is a nakshatra pada?**

A nakshatra pada is one quarter of a nakshatra. Each of the 27 nakshatras spans 13 degrees 20 arcminutes of sidereal longitude and divides into four padas of 3 degrees 20 arcminutes each. Pada determines the Navamsa (D9) sign for any planet at that longitude, which is used for marriage matching, baby naming, and divisional chart analysis.

**How accurate does a Vedic kundli need to be for marriage matching?**

For Ashtakoota Gun Milan to be reproducible, the Moon longitude needs accuracy to within roughly 1 to 2 arcminutes. That is the precision floor where pada output stays stable across calculation engines. Birth time recorded to the nearest minute and ayanamsa pinned explicitly are the two highest-leverage inputs.

**Why do two Vedic astrology APIs return different Gun Milan scores?**

Different ayanamsa choices, different pada-to-navamsa rules, or different Moon sign lord tables. Lahiri, Raman, and KP Newcomb ayanamsas sit about 1 degree apart in 2026, which can flip pada and navamsa assignments near boundaries. Always pin ayanamsa, time precision, and location source before comparing two reports.

**What is a navamsa sign?**

The navamsa is the ninth divisional chart (D9) used in Vedic astrology, primarily for marriage and dharma analysis. Each rashi divides into nine equal navamsas of 3 degrees 20 arcminutes. Pada 1 of any nakshatra maps to the first navamsa of its rashi group; pada 2 to the second, and so on, following a fixed rule per element.

**Does birth time rounding affect Gun Milan?**

Yes. The Moon moves about 0.54 arcminutes per minute of clock time. Rounding birth time to the nearest five or ten minutes adds up to 5.4 arcminutes of Moon position drift. If the Moon sits within that range of a pada boundary, the recorded pada and the calculated pada will disagree. Use the recorded birth time without rounding.

**How do I verify Moon pada output across two providers?**

Run ten test charts with Moon positions deliberately placed within 30 arcminutes of pada boundaries, then compare four fields per chart: Moon sidereal longitude, nakshatra name, pada (1 to 4), and rashi. Disagreements at the boundary cases reveal the ayanamsa or rule differences between providers.

## Conclusion

Pada precision is the difference between a kundli matching report a family can trust and one that contradicts the report on the next app. Pin ayanamsa, capture birth time without rounding, and geocode the birth city before calling the chart endpoint. Build kundli matching with verified pada output via the [Vedic Astrology API](/products/vedic-astrology-api "Vedic Astrology API with kundli, dasha, panchang, KP, and Gun Milan").