# Comet Book vs GeoMemorizer

The clearest difference is update cadence: GeoMemorizer at every 2 weeks against Comet Book's every 6 months. Comet Book's advantage is iOS requirement (12.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Comet Book ships an update every 6 months, GeoMemorizer every 2 weeks. The most recent releases landed on November 1, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Comet Book | GeoMemorizer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (3 ratings)](https://appshunter.io/ios/app/comet-book/id604782335/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 54.9% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 2 weeks** |
| Monetization | Free | — |
| Size | 10 MB | 20 MB |
| Requires iOS | **12.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 9+ | 4+ |
| Developer | [Vixen Co.,Ltd.](https://appshunter.io/developer/536188843) | [Takafumi Nakasu](https://appshunter.io/developer/6816660339) |

## What reviewers say

### Comet Book

[App page](https://appshunter.io/ios/app/comet-book/id604782335)

Discover and track comets with this educational app. It provides real-time direction and elevation data to help you locate celestial objects in the night sky. Explore the solar system in 3D and visualize the movement of comets and planets.

**Highlights:** Comet viewing direction and elevation, Real-time celestial object tracking, 3D Solar System mode, Visualize comet and planet motion, Observing site guidance

**In-app purchases:** none


### GeoMemorizer

[App page](https://appshunter.io/ios/app/geomemorizer/id6816660337)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Comet Book free?

Comet Book is free to download, with no in-app purchases.

### Is GeoMemorizer free?

GeoMemorizer is free to download, with no in-app purchases.

### Do Comet Book or GeoMemorizer have ads?

Neither Comet Book nor GeoMemorizer shows ads.

### Which is updated more often, Comet Book or GeoMemorizer?

Comet Book ships an update every 6 months, and GeoMemorizer every 2 weeks. Most recently, Comet Book was updated on November 1, 2026 and GeoMemorizer on October 29, 2026.

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