Comparison

Celestial Simulation vs Ishigaki Star Guide

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Celestial Simulation

Features
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Celestial Simulation Experience the universe as it truly moves. Celestial Simulation is a high-fidelity, physics-based app that lets you explore and understand celestial motion through real simulations—not animations or guesses. Every event is driven by time, location, and real celestial mechanics. From eclipses and planetary motion to lunar occultations and chaotic three-body dynamics, the app turns complex astronomy into intuitive, visual experiences. Observer-Based Simulation Your location matters. Set your observing position on Earth and watch how celestial events change with latitude, longitude, and time. Every simulation adapts instantly to your chosen place and moment. Solar System Geometry Explore the mechanics of the inner solar system: - Annular and hybrid solar eclipses with umbra and antumbra geometry - Planetary conjunctions and minimum angular separations - Mercury and Venus elongations for optimal visibility - Retrograde motion visualized over days and weeks - Transits of Mercury and Venus across the solar disk Most simulations are continuous and time-accurate. Lunar Occultations See how the Moon moves through the sky: - Occultations of bright stars and planets - Local and global visibility bands - Geometry that explains why an event is visible from certain locations Three-Body Dynamics Go beyond classical orbits and explore real gravitational complexity: - Circular Restricted Three-Body Problem (CR3BP) - Lagrange points L1–L5 with stability insights - Chaotic motion in non-rotating frames - Extreme sensitivity to initial conditions - These simulations reveal how real spaceflight dynamics and celestial chaos work. Special Focus: Total Solar Eclipse 2026 (Europe) A total solar eclipse will cross Europe in 2026 — a rare and unforgettable event. Celestial Simulation lets you explore the full path of totality, simulate eclipse geometry from different locations, and understand how timing and position affect what you will see. Use the simulation to: - Compare observing locations across Europe - Visualize eclipse paths and shadow motion - Plan where and when to experience totality Whether you are preparing a journey or simply exploring the mechanics behind the event, the app helps you understand why the eclipse unfolds the way it does. Built for Exploration - Interactive time control - Clean, focused visualizations - Designed for learners, enthusiasts, and curious minds - No clutter, no gimmicks—just the universe in motion Celestial Simulation is a pocket laboratory for understanding how the sky actually works. Whether you’re learning, teaching, or simply fascinated by celestial mechanics, this app lets you see the physics behind the beauty.

About

Ishigaki Star Guide

Features
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Hold your phone up to the night sky and the stars in front of you appear on screen, named. A star guide built for one sky: Ishigaki Island, Okinawa. Ishigaki sits at 24.6 degrees north. From here the Southern Cross clears the horizon from winter dawns to spring evenings, a sight never seen from mainland Japan. POINT AND FIND AR mode draws constellation lines and star names over the live camera view, so the screen matches the sky above you; with the camera off it works as a plain chart. Only the constellation at the centre of your view lights up, the others fade back. 5,070 stars down to magnitude 6.0, the naked-eye limit, with lines for all 88 constellations. THE SOUTHERN CROSS, WITH TIMES Search for the Southern Cross: if it is up, an arrow at the edge of the screen guides you as you turn towards it; if not, the time machine jumps to the next time it will be. Check tonight's sky before you go outside. STAR NAMES FROM THE YAEYAMA ISLANDS Antares is Beecha-bushi. The Pleiades are Muri-ga-bushi. Polaris is Ninufa-bushi. The Milky Way is Tingara. Tap a star to see the Yaeyama name beside the modern one, with the story attached. Search "Haimuru-bushi" and the Southern Cross comes up. FIND THE CONSTELLATIONS AND COLLECT THEM Follow the arrow until the constellation is in front of you, hold it there, and tap "Found it" to record it in your book. A guide character then talks about that constellation and suggests a nearby one you have not found yet, arrow ready. Eighty-one constellations are reachable from Ishigaki; the ones that barely clear the horizon, like the Southern Cross at 8 degrees, rank as legendary. Records only count at night at the real current time, so the book holds only what you actually looked at. GUIDED PROGRAMMES, SPOKEN Like a planetarium show, a guided programme walks you through the sky one constellation at a time. "Yaeyama Winter Sky: An Introduction" is free: on nights from December to February it takes you from Orion to the Pleiades, the Winter Triangle and Canopus low over the sea, narrated in the unhurried voice of an island elder, so you can keep looking up. Every description card can also be read aloud. More themed programmes will follow. WILL IT BE CLEAR TONIGHT? - Sky Score: cloud, moonlight, humidity, visibility, rain and pressure scored out of 100, with the best hour highlighted (needs a connection) - Tonight's Highlights: end of twilight, moonrise and moonset, the moonless dark window, the Southern Cross transit, active showers - Moon Calendar: a month of phases at a glance FINDING DARK SKY Thirty observing spots around Ishigaki and the Yaeyama Islands, each with a Bortle darkness rating and distance from you, with town lights drawn on the map. Tap one for directions. ALSO INCLUDED - Time machine: step by second to year, or play time forward and watch the sky turn - Deep sky: 19 objects including Omega Centauri, Andromeda and the Orion Nebula - A Milky Way drawn from measured isophote data, Sagittarius bulge and Great Rift included - Meteors from the active shower's radiant at a realistic rate - Sound effects and a gentle haptic tap when you find a constellation - Five languages: Japanese, English, Chinese (Traditional and Simplified), Korean MADE BY A STARGAZING GUIDE OF TEN YEARS Hoshihaku, Inc. has run the Nagareboshi-no-oka stargazing tour on Ishigaki for ten years and guided over 60,000 visitors. The explanations are the answers we give guests in the field. PRIVACY - No account, no sign-up, no name or email to enter anywhere - No advertising, no analytics, no tracking - Settings and your collection stay on your device - Coordinates are sent only to fetch the weather forecast, and are not stored - The camera draws the AR background only; nothing is photographed, saved or sent - The microphone is never used Everything but the weather-based Sky Score works offline, guided programmes included. Bearings come from the magnetometer, which reads inaccurately inside a vehicle or near steel.

Screenshots

Celestial Simulation4 screens
Ishigaki Star Guide4 screens

Verdict

The call

The clearest difference is price: Ishigaki Star Guide at Free against Celestial Simulation's $3.99. Ishigaki Star Guide also leads on iOS requirement (15.1 vs 18.5). On ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Ishigaki Star Guide is free to download; Celestial Simulation costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Scorecard2 real differences · 3 level
Celestial Simulation versus Ishigaki Star Guide: the parameters behind the verdict, then further details
ParameterCelestial SimulationIshigaki Star Guide
Price$3.99Free — better
AdsNoNo
In-app purchasesNoNo
DevicesiPhone, iPadiPhone, iPod
Requires iOS18.515.1 — better
Further details — not scored
Size88 MB32 MB
Age rating4+4+
DeveloperDung Lenobunari arakaki

In-app purchases

None

Celestial Simulation

No in-app purchases

None

Ishigaki Star Guide

No in-app purchases

Questions

Is Celestial Simulation free?
Celestial Simulation costs $3.99, with no in-app purchases.
Is Ishigaki Star Guide free?
Ishigaki Star Guide is free to download, with no in-app purchases.
Do Celestial Simulation or Ishigaki Star Guide have ads?
Neither Celestial Simulation nor Ishigaki Star Guide shows ads.

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