A standard birth chart looks out from Earth. A heliocentric chart shifts the coordinate origin to the Sun. That single change rearranges planetary longitudes, puts Earth among the plotted bodies, and removes the familiar geocentric Sun position. It is useful as a second geometric view of one birth moment, provided the chosen reference frame and its omissions stay visible. A Sun-centred wheel is not an Earth-sky map.
How is a heliocentric chart calculated?
First choose an exact instant. The calculator accepts a calendar date and time in Coordinated Universal Time (UTC). For each selected planet it obtains a three-dimensional vector from the Sun's centre to that body. The vector is rotated into the true ecliptic and equinox of that instant. Its direction around that plane becomes ecliptic longitude, its tilt above or below the plane becomes latitude, and its length is distance in astronomical units (AU). One AU is approximately the mean Sun–Earth distance.
The tropical zodiac divides the longitude circle into twelve equal 30-degree signs beginning at the equinox direction. A longitude of 45° therefore appears as 15° Taurus. The wheel plots longitude only. Two bodies could appear near one another around the rim while having very different ecliptic latitudes or Sun distances, so the accompanying table matters. The wheel may stagger adjacent labels inward for legibility; a staggered label is still at its original longitude.
Why is Earth shown instead of the Sun?
In a heliocentric system the Sun is the origin. An origin does not have a useful longitude measured from itself. Earth, however, has a direction from the Sun and can be plotted like the other planets. If you compare Earth's heliocentric longitude with the geocentric longitude of the Sun for the same instant, their directions are approximately opposite. For an exact numerical comparison, both values must use the same equinox and ecliptic, and you must account for whether each calculation is geometric, apparent, geocentric, or topocentric. A blanket claim of exact opposition between unlike chart outputs would be misleading.
Where are the Moon, houses, and angles?
The Moon is deliberately absent from this compact planetary chart. The Moon orbits Earth and could be represented by a precisely defined Sun-to-Moon vector, but different heliocentric astrological methods handle the Moon in different ways. Omitting it avoids presenting one convention as universal. The calculator includes Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto; Pluto is a dwarf planet astronomically but remains a common astrological chart point.
Houses, Ascendant, Descendant, Midheaven, and Imum Coeli describe relationships between the sky and a specific horizon or meridian on Earth. A Sun-centred chart has no observer standing on that terrestrial horizon. It therefore has no ordinary birth-chart houses or angles. A birthplace is not requested. If you need those elements, use an Earth-centred birth chart with an accurate local birth time and place.
Converting a recorded birth time
Many birth records use local civil time, which may have followed daylight saving rules or a historical standard offset. Convert the record to UTC using the rule for the birth location and date before typing it into this calculator. A current time-zone offset is not reliable for a birth many decades ago. For example, a record of 10:30 at an offset of UTC+02:00 corresponds to 08:30 UTC; at UTC−05:00 it corresponds to 15:30 UTC. A change of several hours moves the faster planets enough to matter near a sign boundary. If the recorded time is uncertain, treat the chart as an approximate time slice rather than a precise personal chart.
Reading a heliocentric position table
- Longitude
- The planet's direction around the ecliptic from 0° Aries. The sign label is a convenient 30-degree partition of the numeric value.
- Latitude
- How far north or south the body lies from the ecliptic plane. This is not geographic latitude.
- Distance
- The body's distance from the Sun in AU. It is not its distance from Earth and is not represented to scale on the zodiac wheel.
- UTC instant
- The single time at which all positions are calculated. A heliocentric chart does not need a terrestrial birthplace.
The result is a coordinate diagram, not a forecast or evidence that a life event will occur. Interpretive traditions vary, especially around Earth as a chart point. Compare the numeric positions with the heliocentric ephemeris if you want to see how a planet moves across multiple dates. For a familiar Earth-view comparison, open the geocentric birth-chart calculator.
Method and further reading
This site calculates the chart locally with Astronomy Engine 2.1.19, using its documented HelioVector and Ecliptic functions. The vectors are geometric heliocentric positions; the ecliptic conversion uses the true ecliptic and equinox of date. This explanation and chart design are original to WitchcraftDaily.