@observerly/astrometry/dist/transit.d.ts

observerly's lightweight, zero-dependency, type safe astrometry library written in Typescript for calculating the position of celestial objects in the sky.

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import { type EquatorialCoordinate, type GeographicCoordinate, type HorizontalCoordinate } from './common';
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export interface Parameters {
    Ar: number;
    H1: number;
}
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export interface Transit {
    /**
     *
     *
     * The local sidereal time of rise.
     *
     *
     */
    LSTr: number;
    /**
     *
     *
     * The local sidereal time of set.
     *
     *
     */
    LSTs: number;
    /**
     *
     *
     * The azimuthal angle (in degrees) of the object at rise.
     *
     *
     */
    R: number;
    /**
     *
     *
     * The azimuthal angle (in degrees) of the object at set.
     *
     *
     */
    S: number;
}
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export interface TransitInstance {
    /**
     *
     *
     * The date and time of rise or set.
     *
     *
     */
    datetime: Date;
    /**
     *
     *
     * The local sidereal time of rise or set.
     *
     *
     */
    LST: number;
    /**
     *
     *
     * The Greenwhich sidereal time of rise or set.
     *
     */
    GST: number;
    /**
     *
     *
     * The local azimuthal angle (in degrees) of the object at rise or set.
     *
     */
    az: number;
}
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export declare const isTransitInstance: (value: unknown) => value is TransitInstance;
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/**
 *
 * isBodyCircumpolar()
 *
 * An object is considered circumpolar if it is always above the observer's horizon
 * and never sets. This is true when the object's declination is greater than 90
 * degrees minus the observer's latitude.
 *
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial coordinate of the observed object.
 * @param horizon - The observer's horizon (in degrees).
 * @returns a boolean indicating whether the target is circumpolar.
 */
export declare const isBodyCircumpolar: (observer: GeographicCoordinate, target: EquatorialCoordinate, horizon?: number) => boolean;
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/**
 *
 * isBodyVisible()
 *
 * An object is visible if it is ever above the observer's horizon. This is true when
 * the object's declination is greater than the observer's latitude minus 90 degrees.
 *
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial coordinate of the observed object.
 * @param horizon - The observer's horizon (in degrees).
 * @returns a boolean indicating whether the target is ever visible for the observer.
 */
export declare const isBodyVisible: (observer: GeographicCoordinate, target: EquatorialCoordinate, horizon?: number) => boolean;
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/**
 *
 * isBodyAboveHorizon()
 *
 * An object is above the horizon if it is above the observer's horizon at the time of observation.
 *
 * @param datetime - The date and time of the observation.
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial or horizontal coordinate of the observed object.
 * @param horizon - The observer's horizon (in degrees).
 * @returns a boolean indicating whether the target is above the horizon for the observer's location and for the time of observation.
 *
 */
export declare const isBodyAboveHorizon: (datetime: Date, observer: GeographicCoordinate, target: EquatorialCoordinate | HorizontalCoordinate, horizon?: number) => boolean;
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/**
 *
 * doesBodyRiseOrSet()
 *
 * An object rises or sets if it is above the observer's horizon at the time of observation.
 *
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial or horizontal coordinate of the observed object.
 * @returns false if the object never rises or sets for the observer, otherwise returns the Ar and H1 transit parameters.
 *
 */
export declare const doesBodyRiseOrSet: (observer: GeographicCoordinate, target: EquatorialCoordinate) => false | Parameters;
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/**
 *
 * getBodyTransit()
 *
 * Determines the local sidereal time and azimuthal angle of rise and set for an object.
 *
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial or horizontal coordinate of the observed object.
 * @returns the transit for the body, or undefined if the body never rises or sets for the observer.
 *
 */
export declare const getBodyTransit: (observer: GeographicCoordinate, target: EquatorialCoordinate) => Transit | undefined;
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/**
 *
 * getBodyNextRise()
 *
 * Determines the next rise time for an object, if at all.
 *
 * @param date - The date to start searching for the next rise.
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial coordinate of the observed object.
 * @param horizon - The observer's horizon (in degrees).
 * @returns The next rise time or False if the object never rises, or True if the object is always above the horizon (circumpolar) for the observer.
 */
export declare const getBodyNextRise: (datetime: Date, observer: GeographicCoordinate, target: EquatorialCoordinate, horizon?: number) => TransitInstance | false;
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/**
 *
 * getBodyNextSet()
 *
 * Determines the next set time for an object, if at all.
 *
 * @param date - The date to start searching for the next set.
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial coordinate of the observed object.
 * @param horizon - The observer's horizon (in degrees).
 * @returns The next set time or False if the object never sets, or True if the object is always above the horizon (circumpolar) for the observer.
 */
export declare const getBodyNextSet: (datetime: Date, observer: GeographicCoordinate, target: EquatorialCoordinate, horizon?: number) => TransitInstance | boolean;
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/**
 *
 * isBodyVisibleForNight()
 *
 * Determines whether an object is visible at some point during the night.
 *
 * @param date - The date to start searching for the next set.
 * @param observer - The geographic coordinate of the observer.
 * @param target - The equatorial coordinate of the observed object.
 * @param horizon - The observer's horizon (in degrees).
 * @returns a boolean indicating whether the object is visible at some point during the night.
 *
 */
export declare const isBodyVisibleForNight: (datetime: Date, observer: GeographicCoordinate, target: EquatorialCoordinate, horizon?: number) => boolean;
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