Sign Ingresses

An ingress occurs when a planet crosses from one zodiac sign into the next — or more precisely, when it crosses a specific ecliptic longitude. The zodiac signs divide the ecliptic into twelve 30-degree segments starting from 0° Aries (the vernal equinox point), so a sign ingress is a longitude crossing at a multiple of 30°.

Why ingresses matter

Ingresses mark natural boundaries in planetary cycles:

• Seasonal markers — The Sun's ingress into Aries (0°) is the vernal equinox; into Cancer (90°) the summer solstice; into Libra (180°) the autumnal equinox; into Capricorn (270°) the winter solstice
• Zodiac transits — In astrological practice, a planet entering a new sign changes the interpretive context
• Planetary cycles — Tracking when slow-moving planets change signs helps map long-term cycles (Saturn changes sign roughly every 2.5 years, Pluto every 12-30 years)

How the API finds ingresses

The API uses the Swiss Ephemeris longitude-crossing algorithm, which iterates through time to find the exact moment a body reaches the target longitude.

Sun and Moon use geocentric longitude — the position as seen from Earth's center. This is the standard for tropical astrology and seasonal calculations.

Other planets use heliocentric longitude (as returned by the Swiss Ephemeris crossing algorithm). This is a technical distinction that matters primarily for precision timing — the difference from geocentric is small for slow-moving outer planets but can be noticeable for Mercury and Venus.

Signs and longitudes

You can search by sign name or by arbitrary longitude:

Using the longitude parameter directly, you can search for any ecliptic longitude — not just sign boundaries. For example, find when the Sun reaches 15° Aries (longitude 15°) or any other degree.

Multiple results and direction

Use count (up to 10) to find consecutive ingresses — for example, the next 5 vernal equinoxes. Use backward=true to search into the past.

Supported bodies

Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Nodes, apogees, and asteroids are not supported for ingress search in v1.

See the /v1/ingresses reference for parameters and response fields.