Arabic Parts/Lots

Arabic Parts — also called Lots — are calculated points in the chart derived from the relationship between three factors: two planetary positions and the Ascendant. They originated in Hellenistic astrology, were transmitted and expanded by medieval Arabic astrologers, and remain an important technique in traditional astrology.

How they work

Every lot follows the same formula pattern:

Lot = Ascendant + Body A - Body B

The result is normalized to 0-360°, giving a point that falls in a specific sign and house. The lot's position in the chart is interpreted like a sensitive point — its sign, house, and aspects to planets all carry meaning.

Day/night reversal

The most important subtlety of lots is sect-based formula reversal. In a day chart (Sun above the horizon), one formula is used. In a night chart (Sun below the horizon), Body A and Body B swap:

This reversal preserves the symbolic relationship between the two bodies relative to the light of the sect (the Sun by day, the Moon by night). The Morphemeris API handles this automatically based on the Sun's position relative to the horizon at the given time and location.

The 7 Hermetic lots

These are the classical lots attributed to the 7 visible planets. Each pairs one planet against the Sun:

The Part of Fortune and the Part of Spirit are by far the most widely used. Fortune represents the circumstances of the body and material life; Spirit represents the soul's intent and conscious purpose.

Why location is required

Unlike most astronomical calculations, lots require the Ascendant — which depends on geographic location and the local horizon. This is why the /v1/lots endpoint requires lat and lon parameters.

House placement

Each lot's position falls in a house, which tells you the life domain where that lot's themes manifest. For example, the Part of Fortune in the 10th house suggests material success through career and public reputation.

API endpoint: /v1/lots (1 credit)