Astronomy & Time

Sun & Moon Data

arevdata now includes a lightweight astronomy layer for interfaces that need contextual seasonal or lunar data without pulling in a heavy astronomy library.

Live astronomy lookup

Import

import {
  moonPhases,
  getMoonPhase,
  getMoonPhaseFraction,
  getMoonIllumination,
  getSeason,
} from "arevdata";

import type {
  MoonPhase,
  MoonPhaseName,
  MoonPhaseSnapshot,
  SeasonHemisphere,
  SeasonInfo,
  SeasonName,
} from "arevdata";

What is included

moonPhases

The canonical 8-phase lunar cycle as typed metadata.

interface MoonPhase {
  index: number;
  key:
    | "new-moon"
    | "waxing-crescent"
    | "first-quarter"
    | "waxing-gibbous"
    | "full-moon"
    | "waning-gibbous"
    | "last-quarter"
    | "waning-crescent";
  name: string;
  description: string;
}

getMoonPhase(date?)

Resolve a date to its approximate moon phase snapshot.

import { getMoonPhase } from "arevdata";

const phase = getMoonPhase("2026-03-23T00:00:00.000Z");

phase.key; // e.g. "waxing-crescent"
phase.name; // "Waxing Crescent"
phase.illumination; // 0..1
phase.ageDays; // days since new moon

getMoonIllumination(date?)

Returns the illuminated portion of the lunar disc as a decimal between 0 and 1.

import { getMoonIllumination } from "arevdata";

getMoonIllumination("2000-01-21T04:40:00.000Z"); // close to 1

getMoonPhaseFraction(date?)

Returns the position in the synodic month as a number from 0 to just under 1.

import { getMoonPhaseFraction } from "arevdata";

getMoonPhaseFraction(new Date()); // 0 <= value < 1

getSeason(date?, hemisphere?)

Meteorological seasons for the northern or southern hemisphere.

import { getSeason } from "arevdata";

getSeason("2026-04-15T00:00:00.000Z");
// { name: "spring", hemisphere: "north", label: "Spring (Northern Hemisphere)" }

getSeason("2026-04-15T00:00:00.000Z", "south");
// { name: "autumn", hemisphere: "south", label: "Autumn (Southern Hemisphere)" }

Good use cases

• Show lunar context in weather, calendar, or travel interfaces
• Add moon-phase trivia or seasonal hints to educational apps
• Generate date-aware labels without relying on a remote API
• Drive region-aware copy like “winter break” or “summer season” by hemisphere