pointBeneathfunction
The place on the Earth where a point of the sky stands overhead at a moment: for a shower's radiant, the middle of the half of the Earth its meteors fall on.
Import it
import { pointBeneath } from "@johnmorrisdotca/chikyu-earth/meteors";Definition
function pointBeneath(sky: { ra: number; dec: number; }, ms: number): GeoPointParameters
| Name | Type | Description |
|---|---|---|
sky | { ra: number; dec: number; } | Right ascension and declination, in degrees. |
ms | number | The moment, in milliseconds since the epoch. |
Returns
GeoPoint
The longitude and latitude of that place, in degrees.
Examples
import { METEOR_SHOWERS, pointBeneath } from "@johnmorrisdotca/chikyu-earth/meteors";
const perseids = METEOR_SHOWERS.find((shower) => shower.code === "PER")!;
const place = pointBeneath(perseids.radiant, Date.UTC(2026, 7, 13, 2));
console.log(place.lat, place.lon.toFixed(0)); // 58 and the longitude then58 56What it prints (run when this page was built)