Most of what is in a birth chart is in the sky. The Sun, the Moon and the planets were really there, at the degrees the chart gives them. The Lots are different. Nothing is standing at the Lot of Fortune. It is a point you build, by measuring the distance between two parts of the chart and laying that same distance off from the Ascendant. It is astrology's geometry rather than its astronomy, and for a long stretch of history it was some of the most important geometry an astrologer did.

They are usually called the Arabic parts, which is only half right. The Lots were used by Greek-speaking astrologers in the Hellenistic period, centuries before they reached the astrologers of the Arabic-speaking world. Those astrologers preserved them, used them heavily and added a great many more, which is how the name stuck.

How a Lot is built

Every Lot has the same recipe. Take two points in the chart. Measure the arc from the first to the second. Then start at the Ascendant and count that same arc forward. Where you land is the Lot.

The Lot of Fortune, in a day chart, is the arc from the Sun to the Moon, laid off from the Ascendant. Put another way: the Lot of Fortune stands in the same relation to your Ascendant as your Moon stands to your Sun. If you were born at a New Moon, with the Sun and Moon together, Fortune falls right on the Ascendant. If you were born at a Full Moon, it falls right opposite, on the Descendant.

The Lot of Spirit reverses the arc: from the Moon to the Sun. So Fortune and Spirit always sit at the same distance from the Ascendant, one on each side of it, like two people standing an equal distance from a doorway.

The Lot of Eros is built from the other two ingredients: in a day chart, the arc from the Lot of Spirit to Venus, laid off from the Ascendant.

Our report calculates these three: Fortune, Spirit and Eros. Many more Lots exist in the old texts, for marriage, for siblings, for illness, for almost anything, but these three are the ones with the clearest meaning and the longest use, and Fortune and Spirit in particular were central to the whole tradition.

Day births and night births

Here is the part most software and most websites get wrong. The formulas reverse between a day birth and a night birth.

Whether you were born by day or by night is called your chart's sect, and it depends on whether the Sun was above or below the horizon at the moment of birth. In a day chart the Sun leads, so Fortune is measured from the Sun to the Moon. In a night chart the Moon leads, so the arc is taken the other way round: Fortune runs from the Moon to the Sun, Spirit from the Sun to the Moon, and Eros from Venus to Spirit.

A calculator that ignores sect puts Fortune and Spirit in each other's places for everyone born at night, roughly half of all charts. That is not a small error, since the two mean nearly opposite things. Our report checks the sect first, tells you whether yours is a day or a night chart and which house the Sun is in, and applies the correct formulas.

An example makes this concrete. Imagine someone born in the early afternoon with Cancer rising at 10°, the Sun at 20° Pisces high above the horizon, and the Moon at 5° Gemini. It is a day chart. The arc from the Sun to the Moon is 75 degrees, so the Lot of Fortune falls 75 degrees past the Ascendant, at 25° Virgo. The Lot of Spirit falls 75 degrees the other way, at 25° Aries. Had the same person been born at night with the same placements, which the sky would not actually allow, the two would simply swap.

What Fortune, Spirit and Eros mean

The Lot of Fortune describes the body, circumstance, and what comes to you whether or not you asked for it: health, material conditions, the luck of the draw. It is tied to the Moon, the luminary of the body and of everything that changes.

The Lot of Spirit describes the mind, intention and action: what you set out to do, your choices and your work in the world. It is tied to the Sun, the luminary of purpose.

The pair is an old and useful distinction: what happens to you, and what you undertake. Most people can name an area of life where things simply arrived, and another where nothing happened until they made it happen. Fortune and Spirit often point straight at those two areas.

The Lot of Eros describes desire: what you want, what attracts you, what you reach for. Because it is built from Spirit and Venus, it is desire as an act of the will rather than as passive longing, the wanting that makes a person buy a ticket rather than just look at the timetable.

How to read a Lot

Read a Lot the way you would read an angle of the chart. First, its sign and house: the house shows where in life the matter plays out. Then its ruler, the planet that rules the sign the Lot falls in, and where that ruler stands in your chart. A Lot is only as able to deliver as its ruler is. In the example above, Fortune in Virgo is ruled by Mercury, so Mercury's condition says a great deal about how the circumstances of that life unfold. Fortune in the tenth house ruled by a strong planet describes something quite different from Fortune in the sixth ruled by a weak one.

Last, and loudest, look for a planet sitting on the Lot. Our report lists any planet within three degrees of each Lot, closest first, because a planet conjunct a Lot is the strongest thing a Lot can say. Jupiter on the Lot of Fortune and Saturn on the Lot of Fortune tell very different stories about what tends to arrive unasked.

Spirit has one more use. It is the point the timing technique of zodiacal releasing is measured from, which is a good reason to know exactly where yours is.

Why the birth time matters so much

Every Lot is measured from the Ascendant, and the Ascendant moves about one degree every four minutes. An error of half an hour moves every Lot by seven or eight degrees, and can move it into another sign and another house. The sect also depends on the time, and a birth close to sunrise or sunset can change from day to night within minutes. With an unknown birth time there are no Lots worth reading, and our report will not calculate them.

If you know your birth time, find your Lots of Fortune, Spirit and Eros here, check which sect you were born in, and read each Lot through its sign, its house and its ruler.

Frequently asked questions

What are the Arabic parts?
Calculated points, each made by measuring the arc between two parts of the chart and laying it off from the Ascendant. Despite the name they come from Hellenistic astrology; the Arabic tradition preserved and extended them.

Which Lots does the report calculate?
Three: the Lot of Fortune, the Lot of Spirit and the Lot of Eros, each with its sign, house, ruler and any planet within three degrees of it.

What is the Lot of Fortune?
In a day chart, the arc from the Sun to the Moon, measured from the Ascendant; at night the arc is reversed. It stands for the body and for circumstance, the part of a life that arrives rather than being chosen.

Why do the formulas change between day and night?
Because sect, whether the Sun was above or below the horizon at birth, reverses the roles of the Sun and the Moon. Ignoring it swaps Fortune and Spirit, which is the commonest error in calculating Lots.

Do I need my birth time?
Yes. Every Lot is measured from the Ascendant, which moves a degree every four minutes, and the sect itself depends on the time. Without a birth time the report does not calculate the Lots.