@observerly/astrometry/dist/earth.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 { Planet } from './planets';
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export declare const earth: Planet;
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export declare const L: {
    A: number;
    B: number;
    C: number;
}[][];
export declare const B: {
    A: number;
    B: number;
    C: number;
}[][];
export declare const R: {
    A: number;
    B: number;
    C: number;
}[][];
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/**
 *
 * getEccentricityOfOrbit()
 *
 * The eccentricity of the Earth's orbit is a measure of how elliptical the Earth's
 * orbit is. The eccentricity of the Earth's orbit is not constant, but varies over
 * time. This function returns the eccentricity of the Earth's orbit for a given date.
 *
 * @param date - The date to get the eccentricity of the Earth's orbit for
 * @returns The eccentricity of the Earth's orbit in degrees
 *
 */
export declare const getEccentricityOfOrbit: (datetime: Date) => number;
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/**
 *
 * getObliquityOfEcliptic()
 *
 * @see EQ22.2 p.147 of Meeus, Jean. 1991. Astronomical algorithms. Richmond, Va: Willmann-Bell.
 *
 * @note This is adopted by the International Astronomical Union (IAU), however the accuracy
 * is NOT satisfactory over a long period of time, the error in ε0 reaches 1" over a period
 * of 2000 years and about 10" over a period of 4000 years.
 *
 * @param datetime - The date to get the obliquity of the ecliptic for
 * @returns The obliquity of the ecliptic in degrees
 *
 */
export declare const getObliquityOfEcliptic: (datetime: Date) => number;
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/**
 *
 * getCoefficientOfEccentricity()
 *
 * The coefficient of eccentricity of the Earth's orbit is a measure of how elliptical the Earth's
 * orbit is. The coefficient of eccentricity of the Earth's orbit is not constant, but varies over
 * time. This function returns the coefficient of eccentricity of the Earth's orbit for a given date.
 *
 * @param datetime - The date to get the coefficient of eccentricity for
 * @returns The coefficient of eccentricity of the Earth's orbit
 */
export declare const getCoefficientOfEccentricity: (datetime: Date) => number;
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