Sidereal Loons Eclipse Timer

A countdown to solar eclipse contact times, for exactly where you're standing.

Free, for macOS, iPhone, and iPad. Coming Soon to the App Store.

Pick any solar eclipse from 2020 through 2050, enter or search for your observing location, and Eclipse Timer counts down to first contact, totality (or annularity), and last contact - with the exact clock time, in your location's own time zone, for each. No account, no ads, no in-app purchases.

Features

Every solar eclipse from 2020 to 2050 (total, annular, hybrid, and partial) is available for modeling. For each eclipse this app can:
- Provide timers counting down to key eclipse times.
- Pull up information on the eclipse Saros series, magnitude, and duration.
- Show orthographic and animated eclipse path maps, plus a link to an interactive Google map.
Countdowns to first contact (C1), totality/annularity begins and ends (C2/C3), and last contact (C4), computed for your exact latitude, longitude, and elevation. Your position can be determined from the device's location services or by geolocation lookup of the name of the location.
Spoken countdown warnings before totality begins and ends, so you don't have to keep checking the screen (You can simulate this feature to know what to expect).
Works offline once a location and eclipse are chosen - useful at the kind of remote, off-grid site eclipse chasers can end up at.
Supports both English and Spanish.

Screenshots

Eclipse Timer on macOS, showing a total solar eclipse countdown for Burgos, Spain — **macOS** - countdown to a total solar eclipse over Burgos, Spain

Eclipse Timer on macOS, showing the countdown window for Burgos, Spain alongside a separate Orthographic Map window for the same eclipse — **macOS** - orthographic eclipse path map window displayedalongside the countdown

Eclipse Timer on iPhone, showing a total solar eclipse countdown for Cairo, Egypt — **iPhone** - countdown to a partial solar eclipse over Cairo, Egypt

Eclipse Timer on iPhone, showing the orthographic eclipse path map for the 2027-08-02 total solar eclipse — **iPhone** - orthographic eclipse path map displayed on iPhone

Eclipse Timer on iPhone, showing the animated eclipse path map for the 2027-08-02 total solar eclipse — **iPhone** - animated eclipse path map displayed on iPhone

Eclipse Timer on iPad in landscape, showing the countdown for Sevilla, Spain alongside the orthographic eclipse path map for the 2027-08-02 total solar eclipse — **iPad** - countdown and orthographic path map for Sevilla, Spain displayed on iPad (landscape)

Eclipse Timer on iPad in landscape, showing the countdown for Sevilla, Spain alongside the animated eclipse path map for the 2027-08-02 total solar eclipse — **iPad** - countdown and animated path map for Sevilla, Spain displayed on iPad (landscape)

Eclipse Timer on iPad in portrait, showing the countdown for Sevilla, Spain alongside the orthographic eclipse path map for the 2027-08-02 total solar eclipse — **iPad** - countdown and orthographic path map for Sevilla, Spain displayed on iPad (portrait)

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Privacy Policy

Effective 2026-08-02

Eclipse Timer does not collect, store, or transmit any personal data to its developer or to any third party. This section explains exactly what location data the app uses and why.

Location data

Eclipse Timer needs an observing location (latitude, longitude, and elevation) to compute eclipse contact times, since these depend on exactly where you're standing. You can provide this in three ways:

Typing coordinates in directly
Searching for a place by name
Tapping "Use Current Location," which asks iOS/macOS for your device's location via Core Location

The app never fills in a location automatically without one of these actions from you. Once entered, your location is stored only on your own device (to remember it between launches and to keep a short "recent locations" list) and is never sent to the developer or to any analytics or advertising service - Eclipse Timer contains no analytics, advertising, or tracking code of any kind.

Network requests the app makes

Eclipse Timer makes network requests only for the following, each initiated by an action you take:

Place-name search and "Use Current Location": handled by Apple's own Core Location / geocoding services on your device, not by the developer.
Orthographic and Animated eclipse maps: downloaded from NASA's Goddard Space Flight Center (eclipse.gsfc.nasa.gov) when you tap to view one, and cached on your device so the same map isn't re-downloaded.
Interactive Google Map: opens a link (hosted by a third party, Xavier Jubier's eclipse mapping site) in your device's default web browser - this happens outside the app, the same as tapping any other link.

None of these requests include your location or any other personal data beyond what's needed to fulfill the specific request (e.g., the place name you typed, or which map image to fetch).

Data the app stores locally

Your selected eclipse, your entered location(s), and your app settings (language, spoken warnings on/off) are stored locally on your device using standard iOS/macOS app storage. This data is not synced to iCloud or any other server, is not accessible to the developer, and is removed if you delete the app.

Children's Privacy

Eclipse Timer is not directed at children and does not knowingly collect any data from anyone, regardless of age.

Changes to this policy

If this policy changes, the updated version will be posted at this same address with a new effective date.

Support & FAQ

How to contact the developer?
Questions, bug reports, or feature requests: - the same address for questions about the Privacy Policy above.

Please include the app version (Settings → About) and, for a bug report, the eclipse and location you had selected when the problem occurred (screenshots can help a lot for this).

How accurate are the predicted times?
Contact times are generally accurate to within about ±5 seconds (and considerably more accurate for near-future eclipses). There are two main limitations to the accuracy:

Uncertainty in Earth's rotation rate (Delta-T), which grows for eclipses further in the future. I have used all the available data on recent "leap second" adjustments I had available to me in summer 2026.
I do NOT include a full lunar limb model, which would account for the effects of the Moon's not perfectly spherical shape on the timing. This is a bigger issue at the edges of the path of totality in particular and can result in errors of a few seconds in the predicted contact times near the edge of the totality path.

Why does the app ask for a location?
Eclipse contact times depend on exactly where you're observing from. You can type coordinates in directly, search by place name, or (optionally) use your device's current location - nothing is filled in automatically without you asking for it.

Which eclipses are covered?
Every solar eclipse (total, annular, hybrid, and partial) from 2020 through 2050.

Does it work offline?
Yes, once a location and eclipse are selected. An internet connection is only needed for the optional Orthographic/Animated/Google map views and for place-name search. And if you view the Orthographic or Animated maps while online, they will be cached on your device for offline viewing.

Is there any sort of warranty?
Are you kidding? This is an academic's part-time project, not a commercial product. There is no warranty of any kind, and the developer is not responsible for any loss or damage resulting from use of this software. The app is provided free of charge.