Enter your birth date, the most reliable time you have and your birthplace. The chart shows the Part of Fortune with its sign, degree and house, next to the Ascendant, Midheaven and Vertex. The formula is applied to day and night births alike; the traditional nocturnal formula is not applied and there is no switch for it.
A worked example
| Term | Longitude | Position |
|---|---|---|
| Ascendant | 314.99° | 14°59′ Aquarius |
| plus Moon | 139.02° | 19°01′ Leo |
| minus Sun | 163.55° | 13°33′ Virgo |
| equals Part of Fortune | 290.47° | 20°28′ Capricorn, house 12 |
Demonstration birth: 1991-09-06 at 18:30 local time, Kyiv, Ukraine (50.4501° N, 30.5234° E), Europe/Kyiv at UTC+3, so 1991-09-06 15:30 UTC. Tropical zodiac, Placidus houses, Swiss Ephemeris 2.10.03. Full result and settings on How to verify your birth chart.
The sum wraps around 360°, and the result matches the point in the demonstration result: 20°28′ Capricorn in house 12. Aspects in the chart are calculated between the 17 bodies, so the Part of Fortune is shown as a position rather than with an aspect list.
The demonstration birth is a day chart: the Sun is in house 7, above the horizon. A traditional astrologer would use the same formula for a day birth and reach the same point. If the nocturnal formula ASC + Sun - Moon were applied to this chart, the point would be at 9°31′ Pisces, a different sign. The gap between the two formulas depends on the distance between the Sun and the Moon: near a New Moon or a Full Moon they nearly coincide, and at other phases they can fall in different signs and houses.
How it is read
In astrology the Part of Fortune is a conventional point associated with ease, support and where things tend to come together. It is read by sign and house, and through the relation of Sun, Moon and Ascendant that the formula encodes. These are reading cues, not measurements. See what the houses mean for the area the house points to.
Settings and limitations
The Ascendant, Sun and Moon come from the Swiss Ephemeris in the tropical zodiac, and the house is a Placidus house. There is no house-system or zodiac switch. A tool set to a sidereal zodiac moves all three terms by about 24 degrees, and the Part of Fortune with them.
Because the formula contains the Ascendant, the Part of Fortune moves with the birth time at least as fast as the Ascendant does, and the Moon adds its own motion of about half a degree an hour. The rate at which the Ascendant moves depends on the place, the date and the sign rising, so there is no fixed number of minutes that keeps the point in one sign or house. Here it sits 9.5° from the nearest sign boundary and 3.57° past the cusp of house 12.
If no time is entered, the moment used is an assumption, and a Part of Fortune computed from it is an assumption twice over: through the Ascendant and through the Moon. See what a chart without birth time can show and how to find your birth time.
Questions
Which formula does NatalChart.AI use?
ASC + Moon - Sun for every chart, day and night alike. There is no setting for the traditional nocturnal formula ASC + Sun - Moon.
Why does another calculator give a different Part of Fortune?
Three common reasons: it applies the nocturnal formula to night births, its Ascendant differs because of the entered time, the timezone offset or the coordinates, or it uses a sidereal zodiac. Compare the inputs and the formula before comparing the result.
Do I need my birth time?
Yes. The formula contains the Ascendant, which depends on the time and place, and the Moon, which moves about half a degree an hour. Without a reliable time the point is an assumption.
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