# Solar System Clock vs SpaSync

The clearest difference is ads: Solar System Clock at none against SpaSync's shown. SpaSync's advantage is update cadence (every 2 weeks vs every 6 weeks). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Solar System Clock sells 1 one-off in-app purchase and SpaSync sells 2 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

Solar System Clock ships an update every 6 weeks, SpaSync every 2 weeks. The most recent releases landed on October 15, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Solar System Clock | SpaSync |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 6 weeks | **Every 2 weeks** |
| Monetization | Free with in-app purchases | — |
| Size | 26 MB | 38 MB |
| Requires iOS | 18.0 | **17.0** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [Sunita George](https://appshunter.io/developer/1777332550) | [Lachlan Ross](https://appshunter.io/developer/1869897232) |

## What reviewers say

### Solar System Clock

[App page](https://appshunter.io/ios/app/solar-system-clock/id6737652569)

Explore the time and positions of celestial bodies across our solar system. View analog and digital clocks for planets, dwarf planets, and moons, with interactive maps and customizable widgets. Understand planetary seasons and translate times between objects.

**Highlights:** Planet and moon time displays, Analog and digital clock formats, Interactive solar system map, Customizable widgets, Planetary season information, Time translation between celestial bodies

**Features:** macOS Compatibility, Apple Watch app, iMessage stickers, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| All Planets and Dwarf Planets | $2.99 | one-time |


### SpaSync

[App page](https://appshunter.io/ios/app/spasync/id6757952574)

**Features:** macOS Compatibility, Family Sharing, Apple Watch app, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| SpaSync Premium (Monthly) | $1.99 | per month |
| SpaSync Premium (Yearly) | $19.99 | per year |


## Frequently asked questions

### Is Solar System Clock free?

Solar System Clock is free to download, with in-app purchases available.

### Is SpaSync free?

SpaSync is free to download, with in-app purchases available.

### Do Solar System Clock or SpaSync have ads?

SpaSync shows ads; Solar System Clock does not.

### Which is updated more often, Solar System Clock or SpaSync?

Solar System Clock ships an update every 6 weeks, and SpaSync every 2 weeks. Most recently, Solar System Clock was updated on October 15, 2026 and SpaSync on October 5, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*