/**
 * nutation.ts — IAU 1980 nutation in longitude and obliquity.
 *
 * Nutation is the short-period wobble of the true equinox about the mean
 * equinox (dominant term: 17.2″ over 18.6 years). Two consumers here:
 *
 *   • Apparent sidereal time (GAST), which drives the ascendant.
 *   • Tropical "apparent" longitudes, if a caller wants them.
 *
 * It is deliberately NOT applied to sidereal planetary longitudes: ayanamsa is
 * defined against the *mean* equinox of date, so the sidereal chain stops at
 * the mean ecliptic of date. (Swiss Ephemeris behaves the same way — sidereal
 * positions are computed with nutation removed.)
 *
 * Series: the 63 largest terms of the IAU 1980 theory (Meeus, *Astronomical
 * Algorithms*, Table 22.A). Truncation error is under 0.001″ — three orders of
 * magnitude below this engine's 1″ target. IAU 2000B would differ by ~0.01″,
 * also negligible here.
 */
export interface Nutation {
    /** Nutation in longitude, degrees. */
    dpsi: number;
    /** Nutation in obliquity, degrees. */
    deps: number;
}
/**
 * Nutation in longitude and obliquity (degrees) at Julian centuries T (TT).
 */
export declare function nutation(T: number): Nutation;