Free astronomy calendar feeds

Subscribe your calendar once and the sky turns up in it: every moon phase, every eclipse, every equinox and solstice, arriving automatically for years. Free, no account, no key, no limit.

The feeds

Copy a link and add it to your calendar app as a subscription, not as an import. A subscription keeps updating; an import is a one-time snapshot that goes stale.

How to subscribe

Google Calendar. On a computer, open Settings, then Add calendar, then From URL. Paste the link and press Add calendar. Google can take up to a day to fetch it the first time, and it refreshes on its own schedule rather than yours.

Apple Calendar (Mac). File, then New Calendar Subscription. Paste the link, press Subscribe, and set Auto-refresh to Every week.

iPhone or iPad. Settings, Apps, Calendar, Accounts, Add Account, Other, Add Subscribed Calendar. Paste the link.

Outlook. In Outlook on the web, open Calendar, then Add calendar, then Subscribe from web. Paste the link and give it a name.

Anything else. Any app that accepts an iCalendar or webcal subscription URL will take these. They are ordinary RFC 5545 files served over HTTPS.

About the times

Every instant is UTC and your calendar app shows it in your own zone. This is the honest way to publish a shared event: a full moon is one moment for the whole planet, and the only thing that differs between two observers is what their clocks read at that moment. So a full moon really can land at 3am for you and lunchtime for somebody else, and both readings are correct.

The instants come from the same engine as the rest of the site and the public API, so a date here, a date on the full moon calendar and a date from the API are the same computation, not three that happen to agree. Positions are good to well under a degree for the Sun, Moon and planets, over roughly 1700 to 2200. The methodology page sets out how everything here is computed.

What these feeds do not do

They carry no location. An eclipse appears in the eclipse feed whether or not it is visible from your sky, because the feed has no way to know where you are and would rather say nothing than guess. There are no moonrise or moonset times for the same reason.

If you want the sky computed for one specific place, that is a different thing and the site has it: sunrise and sunset for any location, the Eclipse Explorer for local eclipse circumstances, and the printable Moon Calendar, which computes moonrise, moonset, phase and illumination for your exact coordinates every day of the year.

Meteor showers are absent, and that one is a licensing matter rather than a design choice. The shower catalogue behind our meteor shower pages comes from a source that publishes no commercial redistribution grant, so we keep it off machine-readable surfaces like this one and the API until that is settled. The computed peak times remain on the pages.

Using these in your own work

You may. The instants are computed facts about the physical universe, and the site's licence dedicates every computed value to the public domain under CC0 1.0, explicitly including commercial products, without restriction and without attribution. Point a club website, a school page, an app or a newsletter at these feeds freely.

A link back is welcome and never required. If you would rather show the sky on your own page than send people here, the free widgets do that, and the API serves the same numbers as JSON.

Frequently asked questions

Is there a catch? Do I need an account?

No account, no key, no limit, and no payment. The instants in these feeds are computed facts about the physical universe, and CycleCalcs dedicates them to the public domain under CC0 1.0: you may use, store, publish and redistribute them, including in commercial products, without restriction and without attribution.

What timezone are the times in?

Every instant is UTC, and your calendar app converts it to your own zone automatically. That is deliberate: a full moon happens at one instant for the whole planet, and only your clock's reading of it differs. If your calendar shows a full moon at 3am, that is genuinely when it happens where you are.

How often does the feed update?

The feed asks your calendar to re-check weekly, and it covers last year through three years ahead, rolling forward automatically. You subscribe once and never touch it again. Nothing in the body changes between year boundaries, so re-checking costs almost nothing.

Why are meteor showers not included?

The shower catalogue we use has no commercial redistribution grant from its source, so we withhold it from machine-readable surfaces like this one and the API until that is resolved. The computed peak times are on the meteor shower pages in the meantime, and each of those pages offers a single-event download.

Will these tell me what is visible from where I live?

No. These feeds carry global instants and no location at all, so an eclipse appears whether or not it is visible from your sky. For rise and set times, local eclipse circumstances and a per-day moon calendar computed for one place, that is what the printable Moon Calendar is for.

Where these dates come from