What are the Arabic parts?

The Arabic parts are calculated points in a chart, better known in their original Greek as lots. Each one is derived from three positions, in the form Ascendant plus one point minus another. They are Hellenistic in origin rather than Arabic, and every one of them needs a birth time. Moon Shine AI computes them with the day and night reversal applied correctly.

The name points at the wrong place

The name is the first thing to get out of the way. These points are not Arabic in origin. They come from Hellenistic astrology, where they were called kleroi, a Greek word meaning lots. Practitioners in the Greek speaking world were using them for centuries before the material reached Baghdad. The Arabic connection is real, but it belongs to transmission rather than invention. Astrologers writing in Arabic preserved the technique, extended the list and passed it on to medieval Europe. The European translators then named the points after the language they had read them in.

That misattribution matters more than a pedantic footnote would suggest. If you believe the lots are a medieval invention, you look for their meaning in medieval sources and stop there. The older Greek material has a different flavor. It treats the lots as structural parts of the chart rather than as decoration added late. Reading them with their Hellenistic logic in view makes them far more coherent. A number of writers now use the word lots for exactly this reason.

The catalog grew enormous over time. Medieval sources list dozens of them, one for almost every subject a person might ask about. Fathers, siblings, journeys, illness, imprisonment, harvests. Modern practice quietly dropped most of that inventory. Four or five points carry nearly all the working weight today, and those are the ones covered across these pages. The rest survive in historical texts and in a few specialist practices.

How a lot is actually built

Every lot is arithmetic performed on three chart positions. The shape is always the same. You take the Ascendant, add the degree of one point and subtract the degree of another. Written out it looks like Ascendant plus A minus B. The answer is a zodiac degree, which then falls in a sign and in a house like any other point. Nothing is orbiting out there. A lot is a calculated position, not a body. Degrees are counted around the full circle, so a result past 360 simply wraps back to the start.

This construction explains why the Ascendant appears in every formula. The lot measures a distance between two points, then projects that distance from the rising degree. Move the Ascendant and the whole lot moves with it. That is also why these points are far more sensitive to birth time than the planets are. A four minute error shifts the Ascendant by roughly one degree, and the lot follows. Planets move slowly enough that a small error in the time barely touches them. The lots have no such cushion.

So the requirement is plain. Without a recorded birth time there is no Ascendant, and without an Ascendant there is no lot. No workaround exists here. Some software will hand you a Part of Fortune anyway by defaulting an unknown time to noon, which produces a number that means nothing at all. If your time is genuinely lost, rectification is the honest route rather than a silent default.

The day and night reversal

The most important technical point about the lots is sect. A chart is either diurnal or nocturnal, and the two are calculated differently. A day chart has the Sun above the horizon, somewhere in houses 7 through 12 of the wheel. A night chart has the Sun below it, in the lower half of the chart. That single fact flips the formula for several lots, including the two most used ones. Nothing else about the chart changes.

The Part of Fortune shows the reversal most clearly. In a day chart it is Ascendant plus Moon minus Sun. In a night chart it is Ascendant plus Sun minus Moon. The Part of Spirit runs the mirror image, so its day formula is Ascendant plus Sun minus Moon and its night formula is Ascendant plus Moon minus Sun. The two lots trade places at sunrise and sunset. That is not a quirk. It is the logic of sect applied consistently.

Here is where the practical trouble starts. A great deal of software never applies the night reversal at all. It computes Ascendant plus Moon minus Sun for everyone and prints the result. For anyone born after dark, that produces the Part of Spirit and labels it Fortune. The same chart can therefore show two different Parts of Fortune in two programs, often in opposite signs. Before you read anything into a placement, check which formula produced it.

The four lots on these pages

The Part of Fortune is the anchor of the group. Classical writers tied it to the body, to health and to the way a person makes a living. The Part of Spirit sits opposite it in function, covering deliberate action and the mind rather than circumstance. Together they form the pair the whole system is built around, and both of them reverse by sect. Neither one is a planet and neither one takes a rulership.

The Part of Eros comes from Paulus Alexandrinus in the fourth century and is calculated from the Part of Spirit, which makes it a second order point. The Part of Marriage is the loosest of the four. Several incompatible formulas circulate under that name, so any reading of it has to say which version was used. That page treats the disagreement openly rather than picking a winner.

None of these points predicts an event. They are descriptive positions, read by sign, by house and by aspect like anything else in the chart. A lot in the 10th house says something about the field it touches. It does not say what will happen or when. Treat them as one layer among many and they earn their place. The tradition used them as description, and description is still what they do best.