Verified against Swiss Ephemeris

An astrology API is only useful if the astronomy is right. Below, every planet, the ascendant, the ayanamsa and today's panchanga from Asterwise are placed next to an independent calculation made directly with the Swiss Ephemeris library, for one fixed birth. You can rerun it yourself in a minute.

Reference birth

DateTimePlaceTimezoneAyanamsa
12 November 198506:45Mumbai, 19.0760 N, 72.8777 EAsia/KolkataLahiri

Sidereal positions (Vedic)

BodyAsterwiseIndependent Swiss EphemerisNakshatraMatch
SunLibra 25.94°Libra 25.94°Vishakhaidentical
MoonLibra 18.18°Libra 18.18°Swatiidentical
MarsVirgo 15.99°Virgo 16.00°Hastaidentical
MercuryScorpio 18.52°Scorpio 18.52°Jyeshthaidentical
JupiterCapricorn 15.96°Capricorn 15.96°Shravanaidentical
VenusLibra 9.37°Libra 9.38°Swatiidentical
SaturnScorpio 5.74°Scorpio 5.75°Anuradhaidentical
Rahu (mean)Aries 14.81°Aries 14.81°Bharaniidentical
AscendantLibra 25.30°Libra 25.30°Vishakhaidentical
Ayanamsa (Lahiri)23.6596°23.6596°identical

Differences in the second decimal come from rounding; the underlying longitudes agree to better than one arc-second. Combustion flags (Moon and Saturn within orb of the Sun), the Yogakaraka and its cancellation for Saturn, Malavya Yoga for Venus in Libra in the first house, and the Rahu dasha balance of about 2.45 years all follow from these positions by the classical rules.

Tropical positions (Western, Placidus)

BodyAsterwiseIndependent Swiss EphemerisMatch
SunScorpio 19.60°Scorpio 19.60°identical
MoonScorpio 11.84°Scorpio 11.84°identical
MercurySagittarius 12.18°Sagittarius 12.18°identical
VenusScorpio 3.03°Scorpio 3.03°identical
MarsLibra 9.65°Libra 9.65°identical
JupiterAquarius 9.62°Aquarius 9.62°identical
SaturnScorpio 29.40°Scorpio 29.40°identical
AscendantScorpio 18.96°Scorpio 18.96°identical
MidheavenLeo 20.34°Leo 20.34°identical

Panchanga, 4 September 2026, Delhi

ElementAsterwiseIndependentMatch
TithiKrishna AshtamiKrishna Ashtamiidentical
NakshatraRohiniRohiniidentical
VaraShukravar (Friday)Fridayidentical

What this looks like inside Claude

The same reference birth, asked for in one sentence in Claude Desktop with the Asterwise MCP server connected. Unedited apart from trimming the wait.

Reproduce it

The independent side uses pyswisseph directly, with the Lahiri ayanamsa and the same Swiss Ephemeris data files. Nothing from Asterwise is imported.

pip install pyswisseph
python3 - <<'PY'
import swisseph as swe
from datetime import datetime
from zoneinfo import ZoneInfo
dt = datetime(1985,11,12,6,45,tzinfo=ZoneInfo("Asia/Kolkata")).astimezone(ZoneInfo("UTC"))
jd = swe.julday(dt.year, dt.month, dt.day, dt.hour + dt.minute/60)
swe.set_sid_mode(swe.SIDM_LAHIRI)
for name, pid in [("Sun",swe.SUN),("Moon",swe.MOON),("Mars",swe.MARS),("Mercury",swe.MERCURY),
                  ("Jupiter",swe.JUPITER),("Venus",swe.VENUS),("Saturn",swe.SATURN),("Rahu",swe.MEAN_NODE)]:
    lon = swe.calc_ut(jd, pid, swe.FLG_SWIEPH | swe.FLG_SIDEREAL)[0][0]
    print(f"{name:8s} sign {int(lon//30)}  {lon%30:.2f}°")
cusps, ascmc = swe.houses_ex(jd, 19.076, 72.8777, b'P', swe.FLG_SIDEREAL)
print(f"Asc      sign {int(ascmc[0]//30)}  {ascmc[0]%30:.2f}°   ayanamsa {swe.get_ayanamsa_ut(jd):.4f}")
PY

Then call POST /v1/astro/natal with the reference birth, or ask the MCP server for the natal chart, and compare.

This page checks Asterwise against the Swiss Ephemeris it is built on. For a check against a source that shares no code with it, see the comparison with NASA JPL Horizons: 80 positions from 1950 to 2050, median difference 0.046 arcseconds.