Planetary Clock vs Heliosphere
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Planetary Clock
Visualize the precise positions of all planets in the Solar System for any given day. It uses accurate NASA data for orbital calculations and relative planet sizing, offering a clear, educational view of celestial mechanics.
- Real-time planet positions
- Accurate orbital calculations
- Uses NASA data
- Relative planet sizing
- Educational solar system view
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Planetary Clock is simple and elegant app what shows positions of all planets of the Solar System at any given day. The app uses precise calculation to determine accurate positions in real time. Sun’s and planets sizes are not to scale in order to show them clearly, but other parameters such as size of orbit, eccentricity, shape of the orbit and position of planets are calculated using precise NASA data. Planets are also realistically sized to each other
Heliosphere
Explore a real-time 3D simulation of the solar system, planets, moons, and spacecraft using accurate astronomical data. Learn about celestial bodies and space missions with educational content and quizzes.
- Real-time 3D solar system simulation
- Live spacecraft tracking
- Deep sky exploration
- Comprehensive astronomy education
- Time travel from 1900 to 2100
- Planet-centric viewing mode
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Explore the solar system at your fingertips. Heliosphere is a real-time 3D solar system simulation powered by NASA JPL Horizons data. It accurately recreates the orbits of planets, moons, comets, and dwarf planets while tracking the real positions of active spacecraft. * Real-time 3D Solar System Simulation — 8 planets, 5 dwarf planets, 10+ moons, and 4 comets — Precise Keplerian orbit calculations based on real astronomical data — Time travel from 1900 to 2100 — Pan, zoom, and rotate for a free-roaming perspective — Switch to planet-centric viewing mode * Live Spacecraft Tracking — Voyager 1, 2 | Pioneer 10, 11 — Cassini | Juno | New Horizons | Parker Solar Probe — Real position data from NASA JPL Horizons API * Deep Sky Exploration — Over 150 bright stars — 530 Milky Way stars — 124 deep-sky objects (Messier, NGC/IC catalogs) * Comprehensive Astronomy Education — 6 difficulty levels from middle school to graduate — Core concepts: Kepler's Laws, gravity, escape velocity, and more — Mission timelines for Voyager, Cassini, New Horizons, and others — 60+ quiz questions to test your knowledge — Historical space event date-guessing challenges * Free for Everyone — All content available at no cost — No ads — 11 languages supported Experience the beauty of the cosmos and the wonder of science through scientifically accurate data and intuitive interaction.
Screenshots
Verdict
The clearest difference is price: Heliosphere at Free against Planetary Clock's $0.99. Heliosphere also leads on update cadence (every 3 days vs every 27 months). Planetary Clock's advantage is rating (4.9 vs 3.0) and in-app purchases (none vs 3). On review sentiment, ads 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
Heliosphere is free to download; Planetary Clock costs $0.99 up front. Heliosphere sells 3 one-off in-app purchases. Planetary Clock asks for nothing beyond the download.
Planetary Clock holds the better App Store score, 4.9 against 3.0. That said, the two scores are not equally well evidenced: Planetary Clock has 34 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 57% of Planetary Clock's written reviews are positive against 50% of Heliosphere's.
Planetary Clock ships an update every 27 months, Heliosphere every 3 days. The most recent releases landed on August 19, 2026 and August 28, 2026 respectively.
| Parameter | Planetary Clock | Heliosphere |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 4.9 (34 ratings) — better | 3.0 (2 ratings) |
| Positive reviews | 57.1% of reviews — better | 50.0% of reviews |
| Number of ratings | 34 — better | 2 |
| Update frequency | Every 27 months | Every 3 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Vision Pro |
| Requires iOS | 11.4 — better | 18.0 |
| Further details — not scored | ||
| Size | 14 MB | 36 MB |
| Age rating | 4+ | 4+ |
| Developer | Piotr Knapczyk | CHUNGKIL KIM |
Customer experience
Planetary Clock
Heliosphere
In-app purchases
Planetary Clock
No in-app purchases
Heliosphere
- 1 Coffee$2.99
- 3 Coffees$8.99
- 5 Coffees$14.99





