/** astroengine houses -- sidereal time, angles, house systems. */
import { EngineData } from "./core.js";
/** Greenwich mean sidereal time, radians (IAU 1982 / Meeus 12.4). */
export declare function gmst(jdUt: number): number;
/** Greenwich apparent sidereal time. */
export declare function gast(data: EngineData, jdUt: number): number;
/** Ecliptic longitude where the house circle with pole `pole` crosses the
 *  ecliptic; `ra` measured like ARMC. The Ascendant is houseCusp(armc+90,
 *  phi); the MC is houseCusp(armc, 0). */
export declare function houseCusp(ra: number, pole: number, eps: number): number;
/** Ascendant, MC, ARMC, obliquity. East longitude positive. */
export declare function angles(data: EngineData, jdUt: number, latDeg: number, lonDeg: number): [number, number, number, number];
/** Vertex (western crossing of prime vertical and ecliptic) and east
 *  point (equatorial ascendant). Radians in, radians out. */
export declare function vertexEastPoint(armc: number, phi: number, eps: number): [number, number];
export declare function housesWholeSign(asc: number): number[];
export declare function housesEqual(asc: number): number[];
export declare function housesPorphyry(asc: number, mc: number): number[];
/** Koch (birthplace): cusps are ascendants at ARMC +/- k/3 of the MC
 *  degree's diurnal semi-arc. Throws where the MC degree is circumpolar
 *  (|phi| >= 90 - eps, matching Swiss Ephemeris). */
export declare function housesKoch(armc: number, phi: number, eps: number): number[];
/** Regiomontanus: equal divisions of the celestial equator; cusp poles
 *  tan P = tan(phi) sin(H). */
export declare function housesRegiomontanus(armc: number, phi: number, eps: number): number[];
/** Campanus: equal divisions of the prime vertical. House circles run
 *  through the horizon's north/south points; cusps are their ecliptic
 *  crossings, assigned in zodiacal order MC->ASC->IC. */
export declare function housesCampanus(armc: number, phi: number, eps: number): number[];
/** Alcabitius: trisect the Ascendant degree's semi-arcs in right ascension;
 *  project cusps along meridians. */
export declare function housesAlcabitius(armc: number, phi: number, eps: number): number[];
/** Morinus: equal RA divisions projected onto the ecliptic by great circles
 *  through the ecliptic poles. Latitude-independent. */
export declare function housesMorinus(armc: number, _phi: number, eps: number): number[];
/** Meridian (axial rotation): equal RA divisions projected along hour
 *  circles. Latitude-independent. */
export declare function housesMeridian(armc: number, _phi: number, eps: number): number[];
/** Polich-Page ('topocentric'): cusp poles tan P = (k/3) tan(phi). */
export declare function housesPolichPage(armc: number, phi: number, eps: number): number[];
/** Vehlow: equal houses with the ASC at the middle of house 1. */
export declare function housesVehlow(armc: number, phi: number, eps: number): number[];
/**
 * Placidus house cusps via the classic iterative semi-arc scheme: for all four
 * intermediate cusps RA = ARMC + offset + f·AD with AD = asin(tan φ · tan δ);
 * offsets 30/60/120/150, f = 1/3, 2/3, 2/3, 1/3. Undefined above the polar
 * circles, as Placidus itself is.
 *
 * Low-level: {@link Engine.chart} calls this for you when the house system is
 * `"placidus"`, falling back to whole-sign near the poles. Inputs and outputs
 * are in **radians**.
 *
 * @param armc Right ascension of the MC, in radians.
 * @param phi Geographic latitude, in radians.
 * @param eps Obliquity of the ecliptic, in radians.
 * @returns The twelve cusp longitudes in radians, house 1 (Ascendant) first.
 */
export declare function housesPlacidus(armc: number, phi: number, eps: number): number[];