ES Module version of lune - calculate the phases of the moon

This library calculates the current phase of the moon as well as finds the dates of the recent moon phases.

Installation

npm install lune-esm

Usage

In Browser

<script type="module">
  import { phase } from 'lune-esm';

  const phaseInfo = phase(new Date());
  console.log(phaseInfo);
</script>

In Node.js

import { phase, phase_hunt, phase_range, PHASE_NEW, PHASE_FIRST, PHASE_FULL, PHASE_LAST } from 'lune-esm';

// Get current moon phase
const currentPhase = phase(new Date());
console.log(currentPhase);

// Hunt for recent moon phases
const phaseHunt = phase_hunt(new Date());
console.log(phaseHunt);

// Get phase range
const start = new Date('2023-01-01');
const end = new Date('2023-02-01');
const fullMoons = phase_range(start, end, PHASE_FULL);
console.log(fullMoons);

API

phase(phase_date)

Finds the phase information for specific date.

• phase_date - Date to get phase information of. Defaults to current date.
• Returns an object with:
  • phase - Phase value (0 to 1)
  • illuminated - Illuminated percent (0 to 1)
  • age - Age of the moon in days
  • distance - Distance from Earth to Moon (km)
  • angular_diameter - Angular diameter of Moon
  • sun_distance - Distance from Earth to Sun (km)
  • sun_angular_diameter - Angular diameter of Sun

phase_hunt(sdate)

Find time of phases of the moon which surround the current date. Five phases are found, starting and ending with the new moons which bound the current lunation.

• sdate - Date to start hunting from (defaults to current date)
• Returns an object containing recent past and future phases:
  • new_date - Date of last new moon
  • q1_date - Date of first quarter moon
  • full_date - Date of full moon
  • q3_date - Date of last quarter moon
  • nextnew_date - Date of next new moon

phase_range(start, end, phase)

Find all phases of a given type within a date range.

• start - Start date
• end - End date
• phase - Phase type (PHASE_NEW, PHASE_FIRST, PHASE_FULL, PHASE_LAST)
• Returns array of dates

Constants

• PHASE_NEW - New moon constant (0)
• PHASE_FIRST - First quarter moon constant (1)
• PHASE_FULL - Full moon constant (2)
• PHASE_LAST - Last quarter moon constant (3)

Example

import { phase } from 'lune-esm';

const currentPhase = phase(new Date());
console.log(`Moon phase: ${currentPhase.phase}`);
console.log(`Illuminated: ${(currentPhase.illuminated * 100).toFixed(2)}%`);

Original Work

This is a derivative work based on lune by Ryan Seys, converted to ES Modules.

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.