---
title: "About Moon Huddle | Moon Huddle"
description: "Moon Huddle is a small set of free moon tools: phase calendar, moonrise times, full moon names and a stargazing planner, all calculated in your browser."
url: https://moonhuddle.cyou/about/
---

# About Moon Huddle

A quiet place to check what the Moon is doing tonight, and on any night you care about.

## What it is

Moon Huddle has five free tools: a [moon phase calendar](https://moonhuddle.cyou/), [moonrise and moonset times](https://moonhuddle.cyou/moonrise-moonset/), [full moon dates and names](https://moonhuddle.cyou/full-moon-dates/), the [moon phase for any date](https://moonhuddle.cyou/moon-phase-by-date/) and a [dark-night stargazing planner](https://moonhuddle.cyou/stargazing-planner/). They are made for people who plan a walk under the full moon, a night of photography or a trip to a dark-sky park, and for anyone curious what the Moon looked like on a day that matters to them.

## How it works

Every number is calculated in your browser from published astronomical methods: the positions of the Sun and Moon follow Jean Meeus's *Astronomical Algorithms* (2nd edition, 1998), and rise, set and twilight follow the definitions of the US Naval Observatory. Nothing is looked up online. The built-in city list and your browser's time zone database give local times, including daylight-saving changes. We checked the results against the Naval Observatory's 2026 tables for London, Sydney and Tromsø: rise, set and twilight times agree to within about a minute, and phase times to within a minute.

## What it is not

Times are for an ideal flat horizon at sea level. Mountains, buildings, your height and unusual weather change what you actually see by a few minutes. For navigation, legal or safety-critical timing, use an official almanac.

## Sources

US Naval Observatory: [phases of the Moon and percent illuminated](https://aa.usno.navy.mil/faq/moon_phases) and [rise, set and twilight definitions](https://aa.usno.navy.mil/faq/RST_defs). Traditional full moon names: [The Old Farmer's Almanac](https://www.almanac.com/full-moon-names). Jean Meeus, *Astronomical Algorithms*, 2nd ed., Willmann-Bell, 1998 ([Open Library record](https://openlibrary.org/books/OL24327734M)).