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import type { EquatorialCoordinate, GeographicCoordinate, SphericalCoordinate } from './common';
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/**
 *
 * getAngularSeparation()
 *
 * The angular separation between two objects is the angle in degrees between the two objects as seen by an observer on Earth.
 *
 * @param A - The equatorial coordinate of the observed object.
 * @param B - The equatorial coordinate of the observed object.
 * @returns The angular separation between the two objects in degrees.
 *
 */
export declare const getAngularSeparation: (A: SphericalCoordinate, B: SphericalCoordinate) => number;
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/**
 *
 * getAntipodeCoordinate()
 *
 * The antipode of an object is the point on the celestial sphere that is diametrically opposite to the observed object.
 *
 * @param A - The coordinate of the observed object, in Spherical coordinates (accepts Equatorial, Horizontal, and Ecliptic coordinates).
 * @returns The antipode of the observed object, in Spherical coordinates.
 */
export declare const getAntipodeCoordinate: (A: SphericalCoordinate) => SphericalCoordinate;
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/**
 *
 * getNormalisedSphericalCoordinate()
 *
 * Normalises a Spherical coordinate to a value between 0 and 360 degrees in the
 * longitude and -90 to 90 degrees in the latitude.
 *
 * @param A - The Spherical coordinate to normalise.
 * @returns The normalised Spherical coordinate.
 *
 */
export declare const getNormalisedSphericalCoordinate: (A: SphericalCoordinate) => SphericalCoordinate;
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/**
 *
 * getGreenwhichSiderealTime()
 *
 * The Greenwich Sidereal Time (GST) is the hour angle of the vernal
 * equinox, the ascending node of the ecliptic on the celestial equator.
 *
 * @param date - The date for which to calculate the Greenwich Sidereal Time (GST).
 * @returns Greenwich Sidereal Time as number - the Greenwich Sidereal Time (GST) of the given date normalised to UTC.
 *
 */
export declare const getGreenwhichSiderealTime: (datetime: Date) => number;
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/**
 *
 * @alias getGreenwhichSiderealTime()
 *
 */
export declare const GST: (datetime: Date) => number;
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/**
 *
 * getLocalSiderealTime()
 *
 * The Local Sidereal Time (LST) is the hour angle of the vernal
 * equinox, the ascending node of the ecliptic on the celestial equator.
 *
 * @param date - The date for which to calculate the Local Sidereal Time (LST).
 * @param longitude - The longitude of the observer in degrees.
 * @returs Local Sidereal Time as number - the Local Sidereal Time (LST) of the given date normalised to UTC.
 *
 */
export declare const getLocalSiderealTime: (datetime: Date, longitude: number) => number;
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/**
 *
 * @alias getLocalSiderealTime()
 *
 */
export declare const LST: (datetime: Date, longitude: number) => number;
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/**
 *
 * getHourAngle()
 *
 * The Hour Angle (HA) is the angular distance along the celestial equator
 * from the observer's meridian to the hour circle of a celestial body.
 *
 * @param date - The date for which to calculate the hour angle.
 * @param ra - Right Ascension of the target in degrees.
 * @param longitude - The longitude of the observer in degrees.
 * @returns The Hour Angle (HA) of the given date.
 *
 */
export declare const getHourAngle: (datetime: Date, longitude: number, ra: number) => number;
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/**
 *
 * getObliquityOfTheEcliptic()
 *
 * The obliquity of the ecliptic is the angle between the ecliptic and the celestial
 * equator, and is used to convert between ecliptic and equatorial coordinates.
 *
 * @param date - The date for which to calculate the obliquity of the ecliptic for.
 * @returns The obliquity of the ecliptic in degrees.
 *
 */
export declare const getObliquityOfTheEcliptic: (datetime: Date) => number;
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/**
 *
 * getParallacticAngle()
 *
 * The parallactic angle is the angle between the great circle that passes through
 * the celestial object and the zenith, and the great circle that passes through
 * the celestial object and the celestial pole.
 *
 * @param date - The date for which to calculate the parallactic angle for.
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial coordinate of the observed object.
 * @return The parallactic angle of the observed object in degrees.
 *
 */
export declare const getParallacticAngle: (datetime: Date, observer: GeographicCoordinate, target: EquatorialCoordinate) => number;
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