Eclipse Countdown vs Eclipse Simulator
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
Eclipse Countdown
This astronomical tool provides precise sub-second solar eclipse timings and interactive maps. It guides users through the eclipse experience with real-time calculations, audio cues, and a list of phenomena to observe.
- Precision timing engine
- Interactive mapping
- Live audio synchronization
- List of phenomena to observe
- Lunar limb profile corrections
- 3D computational models
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The Eclipse App is a high-fidelity astronomical tool engineered for observers who demand absolute accuracy as well as beginners who need a guide through the exceptional experience of their first total solar eclipse. Powered by the latest 3D computational models developed by the Besselian Elements Team, this App provides accurate sub-second eclipse contact timings using lunar limb profile corrections. Whether you are a professional researcher, an astrophotographer, or a dedicated eclipse chaser, this app provides the rigorous data necessary for a successful expedition, from interactive map useful for planning, to simulating the countdown and exercise with the equipment, and for real time tracking in case you are moving in search of the right spot. Core Features: β’ Precision Timing Engine: Real-time calculations of Contact Times based on your exact GPS coordinates β’ Interactive Mapping: High-resolution path-of-totality overlays including umbral limits an the center-line. The IQP method accounts for the topography on both the lunar limb and at the observer site, as well as relying on an improved value for the eclipse solar radius (959.95" Β± 0.05", based on research by the Besselian Elements Team). The eclipse center-line and the northern and southern limits of the umbral shadow path also account for these three factors. Hence, these lines are not smooth lines, as in most publicly-available eclipse maps, but are noticeably jagged. Two lines are presented at each path limit corresponding to two values of the eclipse solar radius (959.90" and 960.00") in order to display a region of uncertainty rather than a single limit line. β’ Live Audio Synchronization: A sophisticated voice-cue system that announces critical contact phases and astronomical phenomena (e.g., shadow bands, corona visibility, and solar filtration changes), allowing you to keep your eyes on the sky or your equipment. β’ List of phenomena to observe during the eclipse at every step, so that you can be reminded to watch at the right time Designed for the Rigorous Observer: The Eclipse App eliminates the margin of error inherent in simplified models. Prepare for the next Great Eclipse with the most scientifically robust tool available on the App Store.
Eclipse Simulator
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Eclipse Simulator is an educational and investigative tool for finding unusual solar and lunar eclipses by combining an observing location, horizon conditions, and long-term Earth-rotation variation (ΞT). Its search catalog spans astronomical year -999 (1000 BCE) through 5000 CE. Study each event through maps, a ground-level view, and contact times. Key features β’ Search solar and lunar eclipses by date range, eclipse type, location, and other available criteria. β’ Narrow the search with an observing location, solar horizon conditions near sunrise or sunset, lunar moonrise or moonset, and ΞT. β’ View solar-eclipse center and limit lines, partial-eclipse regions, and lunar-eclipse visibility on Apple Maps. β’ Choose an observing location and play the changing alignment of the Sun, Moon, and shadow from the ground. β’ Inspect the contact times that exist for the event, including C1βC4 for solar eclipses and P1βP4/U1βU4 for lunar eclipses. β’ Compare the standard ΞT model with alternative scenarios to understand how uncertainty affects historical and future timing and paths. β’ View stars and constellation lines adjusted to the selected event time instead of showing todayβs sky. β’ Share the selected event as CSV or JSON and the displayed screen as PNG or PDF. On iPhone, the app uses focused screen-by-screen navigation. On iPad, its wider layout keeps the catalog and event workspace within easier reach. If you grant location access, it is used only to set the observing point to your current location. You can also select a point on the map or enter coordinates. About time and accuracy Results are modeled values derived from the ephemeris, ΞT model, and Earth-orientation model recorded with the bundled data. The broad search catalog includes a low-precision analytical ephemeris, while the calculation provenance for a selected event is shown in the app and exports. Uncertainty remains in ΞT, future civil-time rules, polar motion, lunar-limb terrain, local terrain, and weather. Historical and future views use present-day Apple Maps and do not reconstruct borders or cities from the selected era. Lunar-eclipse color is schematic. Use the app for education, understanding astronomical geometry, and comparing model assumptions. Do not rely on it as a guaranteed value for observation planning, navigation, scientific conclusions, or safety-critical decisions.
Screenshots
Verdict
The clearest difference is price: Eclipse Simulator at Free against Eclipse Countdown's $1.99. Eclipse Simulator also leads on update cadence (every 4 days vs monthly). Eclipse Countdown's advantage is iOS requirement (15.1 vs 18.0). On ads, in-app purchases and device support there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Eclipse Simulator is free to download; Eclipse Countdown costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Eclipse Countdown ships an update monthly, Eclipse Simulator every 4 days. The most recent releases landed on September 29, 2026 and October 6, 2026 respectively.
| Parameter | Eclipse Countdown | Eclipse Simulator |
|---|---|---|
| Price | $1.99 | Free β better |
| Positive reviews | 100.0% of reviews | β |
| Update frequency | Monthly | Every 4 days β better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | β |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Requires iOS | 15.1 β better | 18.0 |
| Further details β not scored | ||
| Size | 49 MB | 3.2 GB |
| Age rating | 4+ | 4+ |
| Developer | BESSELIAN ELEMENTS PTY LTD | Fumikazu Kondo |
In-app purchases
Eclipse Countdown
No in-app purchases
Eclipse Simulator
No in-app purchases





