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Chikyu Earth地球

A line-drawn globe of the world's countries that turns at the Earth's own rate, with an optional realistic Earth from space and markers for any place.

Chikyu is the Japanese word 地球 for the Earth. About the name

Contents

Reference · Passes: when a satellite crosses the sky over a place

passPathfunction

The satellite's track across the sky for a pass: a point every stepSeconds from the pass's start to its end, with the first and last on the start and the end. Draw it with skySvg.

Import it

import { passPath } from "@johnmorrisdotca/chikyu-earth/passes";

Definition

function passPath(set: ElementSet, observer: Observer, pass: SatellitePass, stepSeconds?: number): PathPoint[]

Parameters

NameTypeDescription
setElementSet

The satellite's elements (the one the pass was found from).

observerObserver

Where the watcher stands.

passSatellitePass

A pass from findPasses.

stepSeconds (optional)number

Seconds between points (5 by default).

Returns

PathPoint[]

The points, in time order.

Examples

import { findPasses, passPath } from "@johnmorrisdotca/chikyu-earth/passes";

const iss = {
  OBJECT_NAME: "ISS (ZARYA)",
  EPOCH: "2026-11-02T10:25:21.580320",
  MEAN_MOTION: 15.49150046,
  ECCENTRICITY: 0.0007139,
  INCLINATION: 51.6332,
  RA_OF_ASC_NODE: 335.9757,
  ARG_OF_PERICENTER: 339.3739,
  MEAN_ANOMALY: 20.6961,
  NORAD_CAT_ID: 25544,
  BSTAR: 0.00012,
  MEAN_MOTION_DOT: 0.0001,
  MEAN_MOTION_DDOT: 0,
};
const place = { latitude: 51.5, longitude: -0.13 };
const day = Date.UTC(2026, 10, 3);
const [first] = findPasses(iss, place, { from: day, to: day + 3 * 86_400_000 }, { all: true });
console.log(first ? passPath(iss, place, first).length : 0);
83

What it prints (run when this page was built)

View sourceEdit on GitHubMade from the source of @johnmorrisdotca/chikyu-earth 0.51.1.