Working with Sidereal Positions

The sidereal zodiac is fixed to the stars rather than the equinoxes. It's used in Vedic/Jyotish astrology and some Western sidereal traditions. The difference between tropical and sidereal zodiacs is called the ayanamsha.

Requesting sidereal positions

Add the sidereal parameter to any position or chart request:

# Lahiri ayanamsha (Indian government standard)
curl "https://api.morphemeris.com/v1/positions?\
datetime=2024-03-20T12:00:00Z\
&sidereal=lahiri" \
  -H "Authorization: Bearer morphemeris_live_YOUR_KEY"

The response positions will be in the sidereal zodiac. For example, the Sun at the tropical vernal equinox (0° Aries tropical) would appear around 6° Pisces in the Lahiri sidereal zodiac.

Full Vedic chart

For a traditional Jyotish chart, combine sidereal positions with whole-sign houses:

curl "https://api.morphemeris.com/v1/chart?\
datetime=1990-06-15T18:30:00Z\
&lat=40.7128\
&lon=-74.0060\
&sidereal=lahiri\
&system=whole_sign\
&bodies=sun,moon,mercury,venus,mars,jupiter,saturn,mean_node" \
  -H "Authorization: Bearer morphemeris_live_YOUR_KEY"

The response includes an ayanamsha field showing the exact offset used:

{
  "data": {
    "positions": [...],
    "houses": {...},
    "ayanamsha": 23.7190
  }
}

Checking the ayanamsha value

To see the ayanamsha value for any system without computing positions:

# Single system
curl "https://api.morphemeris.com/v1/ayanamsha?datetime=2024-01-01T00:00:00Z&system=lahiri"

# All 47 systems at once
curl "https://api.morphemeris.com/v1/ayanamsha?datetime=2024-01-01T00:00:00Z&system=all"

Common ayanamsha choices

See Ayanamshas for the full list of 47 systems.

Tips

• The sidereal parameter works with any body or house endpoint — not just /v1/chart.
• You can specify ayanamsha by name (lahiri) or Swiss Ephemeris ID (1).
• Sidereal house cusps shift by the ayanamsha amount from their tropical positions.