@observerly/astrometry/dist/conjunction.js

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

import { getAngularSeparation as S } from "./astrometry.js";
import { convertEclipticToEquatorial as T, convertEquatorialToHorizontal as m } from "./coordinates.js";
import { getPlanetaryGeocentricEclipticCoordinate as j, getPlanetaryPositions as M } from "./planets.js";
// @license        Copyright © 2021-2023 observerly
const p = 3, P = (a, s, h, o = {
  horizon: 6,
  angularSeparationThreshold: p
}) => {
  const [t, e] = h, { horizon: r = 6, angularSeparationThreshold: u = p } = o, l = T(a, j(a, t)), n = T(a, j(a, e)), i = m(a, s, l), c = m(a, s, n);
  if (i.alt < r || c.alt < r)
    return !1;
  const f = S({
    θ: i.alt,
    φ: i.az
  }, {
    θ: c.alt,
    φ: c.az
  });
  if (f > u)
    return !1;
  const g = [
    {
      name: t.name,
      ...i,
      ...l
    },
    {
      name: e.name,
      ...c,
      ...n
    }
  ];
  return {
    datetime: a,
    targets: g,
    angularSeparation: f,
    ra: (l.ra + n.ra) / 2,
    dec: (l.dec + n.dec) / 2
  };
}, y = (a, s, h = {
  horizon: 6,
  angularSeparationThreshold: p
}) => {
  const { horizon: o = 6, angularSeparationThreshold: t = p } = h, [e, r] = s;
  if (e.alt < o || r.alt < o)
    return !1;
  const u = S({
    θ: e.alt,
    φ: e.az
  }, {
    θ: r.alt,
    φ: r.az
  });
  return u > t ? !1 : {
    datetime: a,
    targets: s,
    angularSeparation: u,
    ra: (e.ra + r.ra) / 2,
    dec: (e.dec + r.dec) / 2
  };
}, D = (a, s, h, o = {
  horizon: 6,
  angularSeparationThreshold: 3,
  stepMinutes: 20
}) => {
  let { from: t, to: e } = a;
  const { horizon: r = 6, angularSeparationThreshold: u = p, stepMinutes: l = 20 } = o;
  for (; t <= e; ) {
    const n = P(t, s, h, {
      horizon: r,
      angularSeparationThreshold: u
    });
    if (n)
      return n;
    t = new Date(t.getTime() + l * 6e4);
  }
}, H = (a, s, h = {
  horizon: 6,
  angularSeparationThreshold: p,
  stepMinutes: 20
}) => {
  let { from: o, to: t } = a;
  const { horizon: e = 6, angularSeparationThreshold: r = p, stepMinutes: u = 20 } = h;
  for (; o <= t; ) {
    const l = y(o, s, {
      horizon: e,
      angularSeparationThreshold: r
    });
    if (l)
      return l;
    o = new Date(o.getTime() + u * 6e4);
  }
  return !1;
}, R = (a, s, h = {
  horizon: 6,
  angularSeparationThreshold: p,
  stepMinutes: 20
}) => {
  const o = /* @__PURE__ */ new Map();
  let { from: t, to: e } = a;
  const { horizon: r = 6, angularSeparationThreshold: u = p, stepMinutes: l = 20 } = h;
  for (; t <= e; ) {
    const n = M(t, s);
    for (let i = 0; i < n.length; i++)
      for (let c = i + 1; c < n.length; c++) {
        if (n[i].alt < r || n[c].alt < r)
          continue;
        const f = n[i], g = n[c], d = [f.name, g.name].sort().join("-"), z = S({
          θ: n[i].alt,
          φ: n[i].az
        }, {
          θ: n[c].alt,
          φ: n[c].az
        });
        if (z <= u && // biome-ignore lint/style/noNonNullAssertion: This is a false positive. The conjunctions map is initialized above.
        (!o.has(d) || o.get(d).angularSeparation > z)) {
          const w = {
            datetime: t,
            targets: [f, g],
            angularSeparation: z,
            ra: (f.ra + g.ra) / 2,
            dec: (f.dec + g.dec) / 2
          };
          o.set(d, w);
        }
      }
    t = new Date(t.getTime() + l * 6e4);
  }
  return o;
};
export {
  H as findConjunction,
  D as findPlanetaryConjunction,
  R as findPlanetaryConjunctions,
  y as isConjunction,
  P as isPlanetaryConjunction
};
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