# Comet Book vs CassiniMIMI

Comet Book and CassiniMIMI both sit at 5.0 stars, but that hides the real split: 100% of CassiniMIMI's written reviews are positive against 55% of Comet Book's. CassiniMIMI also leads on update cadence (weekly vs every 6 months) and iOS requirement (8.0 vs 12.0). On price, rating, ratings volume and ads there is nothing between them.

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

On the App Store both sit at effectively the same score — 5.0 for Comet Book against 5.0 for CassiniMIMI. Both are backed by a comparable volume of ratings — 2 and 2 respectively. Written reviews are what separate them: 55% of Comet Book's written reviews are positive against 100% of CassiniMIMI's.

Comet Book ships an update every 6 months, CassiniMIMI weekly. The most recent releases landed on October 6, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Comet Book | CassiniMIMI |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (2 ratings)](https://appshunter.io/ios/app/comet-book/id604782335/reviews) | [5.0 (2 ratings)](https://appshunter.io/ios/app/cassinimimi/id1153077273/reviews) |
| Number of ratings | 2 | 2 |
| Positive reviews | 54.9% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 months | **Weekly** |
| Monetization | Free | Free |
| Size | 10 MB | 19 MB |
| Requires iOS | 12.0 | **8.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 9+ | 4+ |
| Developer | [Vixen Co.,Ltd.](https://appshunter.io/developer/536188843) | [Johns Hopkins University Applied Physics Laboratory](https://appshunter.io/developer/473217885) |

## 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


### CassiniMIMI

[App page](https://appshunter.io/ios/app/cassinimimi/id1153077273)

Explore stunning images and data from NASA's Cassini mission to Saturn. This app provides access to energetic particle data, ENA images, and spectrograms from Saturn's magnetosphere. Discover new scientific releases and browse daily updated plots and movies.

**Highlights:** Energetic charged particle environment study, Energetic Neutral Atom (ENA) imaging of Saturn, Spectrograms and plots from particle detectors, Access to NASA's Planetary Data System (PDS), Daily updated plots and movies, Selectable data by source, type, date, and style

**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 CassiniMIMI free?

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

### Which has better reviews, Comet Book or CassiniMIMI?

Comet Book and CassiniMIMI are both rated 5.0 out of 5 on the App Store, from 2 and 2 ratings respectively.

### Do Comet Book or CassiniMIMI have ads?

Neither Comet Book nor CassiniMIMI shows ads.

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

Comet Book ships an update every 6 months, and CassiniMIMI weekly. Most recently, Comet Book was updated on October 6, 2026 and CassiniMIMI on October 8, 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.*