Hellenistic time-lords

Time-lord techniques divide a life into periods, each ruled by a planet or a sign, and ask which lord is active at a given moment. Caelus computes the classical Hellenistic and Persian methods as deterministic arithmetic on the positions it already validates against Swiss Ephemeris. No new ephemeris, and every convention is stated, not assumed. None of this is interpretation: the engine returns the lords and their dates; the meaning is yours.

All of these take a natal Julian Day (UT). Convert a local birth time with caelus-birth first (see Computing Charts).

import { julianDay } from "caelus";
const natal = julianDay(1990, 6, 10, 14, 30);   // UT

Lots (Arabic parts)

The seven Hermetic lots (Fortune, Spirit, Eros, Necessity, Courage, Victory, and Nemesis) are arcs cast from the Ascendant, each reversing direction between a day and a night chart. Fortune and Spirit are symmetric about the Ascendant.

import { Engine, lots } from "caelus";
import { embeddedData } from "caelus/data-embedded";
const engine = new Engine(embeddedData);

const l = lots(engine, natal, 27.95, -82.46);
l.fortune;   // longitude of the Lot of Fortune
l.spirit;    // Spirit is Fortune reflected across the Ascendant

Profections

The Ascendant advances one whole sign per year of life; the profected sign's traditional ruler is the lord of the year. The monthly profection advances one further sign per twelfth of the year.

import { profectionAt } from "caelus";
const target = julianDay(2025, 6, 10);
const p = profectionAt(engine, natal, target, 27.95, -82.46);
p.age_years;        // completed years
p.annual.lord;      // lord of the year

Firdaria

The Persian firdaria divides life into nine periods totalling seventy-five years (the seven planets in the firdaria order, then the two nodes), each planetary period split into seven sub-periods. A day chart begins with the Sun, a night chart with the Moon.

import { firdariaAt } from "caelus";
const f = firdariaAt(engine, natal, julianDay(2025, 6, 10), 27.95, -82.46);
f.major;   // the major-period lord active now
f.sub;     // the sub-period lord

Zodiacal releasing

Released from a lot, usually Spirit (career and action) or Fortune (body and circumstance), periods unfold sign by sign across four nested levels. Caelus uses the standard Valens/Schmidt convention: years of exactly 360 days, each level a twelfth of the one above, and the loosing of the bond, where a level that loops back to its starting sign jumps to the opposite sign instead.

import { zrAt } from "caelus";
const z = zrAt(engine, natal, julianDay(2025, 6, 10), 27.95, -82.46, "spirit");
z.l1;   // the major (L1) sign active now
z.l2;   // the L2 sub-period sign

Primary directions

The diurnal rotation of the sphere carries a planet to an angle or to another planet; the arc of rotation, converted by a time key, gives the age of the direction. Caelus computes directions to the four angles and, with the Placidus semi-arc method, between planets. The key is Naibod (0.9856° per year) or Ptolemy (1° per year).

import { primaryDirections, mundaneDirections } from "caelus";
// to the angles, within 90 years
primaryDirections(engine, natal, 27.95, -82.46);
// planet-to-planet (mundane) directions
mundaneDirections(engine, natal, 27.95, -82.46);

The full signatures are in the API Reference. For the Vedic time-lord systems (the Vimshottari, Yogini, and Ashtottari dashas), see Vedic & Jyotish.