# JupiterMoons

> Astronomy app for observing Jupiter's moons and Great Red Spot. (iPhone/iPad app by Guidebook Inc.)

- Source: https://appshunter.io/ios/app/jupitermoons/id577009038 (this page in markdown: same URL + `.md`)
- Developer: [Guidebook Inc](https://appshunter.io/developer/1387977271)
- Category: Education, Entertainment
- Price: $2.99
- Rating: 3.90/5 from 10 App Store ratings · 27 written reviews indexed
- Age rating: 4+
- Requires: iOS 8.0 · 40 MB
- Languages: English
- Released: 2012-11-15
- Data updated: 2026-06-10
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/jupitermoons/id577009038/reviews.md

## What is JupiterMoons?

JupiterMoons is your essential guide to observing the king of planets whenever Jupiter reigns over the night sky. 

Sky & Telescope’s app helps you locate Jupiter’s four largest moons and time transits of the Great Red Spot with an easy-to-use interface. (The moons’ orbits are shown to scale with respect to Jupiter.) Plus, learn more about what makes these fascinating solar system denizens tick.

Observe Jupiter
•  Locate Io, Europa, Ganymede, and Callisto at the specified date and time — unlike in Galileo’s day, they’re clearly labeled.
•  Zoom in by tapping on the screen to better watch accurately timed Great Red Spot crossings and moon transits and eclipses. Or zoom out for a full view of the moons’ orbits. 

Take Command
•  Use the time controls to step through the seconds or hours, or speed through days or even years to see where the moons will be down the line. 
•  Customize your view to match what you see through your telescope.

Focus on the Details
•  Click on any item in JupiterMoons’ complete events calendar to see the action. The calendar lists all the Jupiter-related happenings for the day: moon eclipses and transits, Great Red Spot transits, and moon-shadow transits. 
•  Learn more about Jupiter and its ice-and-fire moons with our encyclopedic descriptions, accompanied by spectacular images.

Please note: this application is designed to work in landscape orientation only so that you may view Jupiter, the Great Red Spot, and the Galilean satellites at their best.

## Key features

- Locate Io, Europa, Ganymede, and Callisto
- Time Great Red Spot transits
- Visualize moon orbits to scale
- Step through time controls
- Customize telescope view
- View events calendar
- Learn about Jupiter and moons

## Recent user reviews (10 of 27)

All indexed reviews: https://appshunter.io/ios/app/jupitermoons/id577009038/reviews.md

### 2/5 — Needs an update badly

*2024-12-05*

Sure would be nice if they updated this and the Saturn moons apps. In particular, they need to allow greater zoom range to fit all the moons on the screen when they are far from the planet, and the Great Red Spot on Jupiter has drifted enough that the app no longer is helpful for finding out when it will be visible.

### 3/5 — GRS transit timings way off

*2022-10-30*

The longitude of the Great Red Spot drifts continually and the app should be updated more frequently so that GRS transit timings are more accurate. Currently they are about 50 minutes too early.

### 5/5 — Great for an astrophotographer

*2022-10-11, version 1.1*

When the sky is clear I shoot photos of Jupiter, but have no idea which moon is where. This app helps me figure it out. It also helps me plan ahead to see if I can capture the great red Spot that night. Highly recommended for anyone who does planetary photography.

### 4/5 — No shadows displayed for Callisto, Europa and Ganymede’s transits

*2021-11-21*

Good app, but only Io’s shadow si displayed on the simulated view.

### 5/5 — Perfect for anyone interested in Jupiter!

*2021-08-19*

This app was incredibly useful to see the moons of Jupiter during the opposition - where Jupiter is brightest - in August 2021!

### 5/5 — Good pocket companion

*2020-08-13*

This app is a clean, simple observing guide that enables you to determine what you’re looking at when you observe Jupiter, and also when transits of Galilean moons and the GRS will occur.

### 1/5 — Would like my money back thanks

*2019-06-10*

Refund please

### 4/5 — Wide Angle needs to be wider

*2018-05-08, version 1.1*

The only knock on this app is that the wide-angle view does not allow sufficient room for Callisto much of the time.

### 3/5 — Decent - needs date/time control

*2018-05-05, version 1.1*

This WOULD be a good app if it let you set your own time, rather than going off UT. Because that’s a 7 hour difference, when it gives me “today’s” events, it’s useless to me because technically anything I’m going to look at tonight is “tomorrow” according to the app. But you can’t switch to any date other than today on the “Events” page (if I’m wrong, please someone show me how!). You can move back and forth in time on the chart page, but not the event page, which is the page that would actually be useful for organizing my viewing.

### 3/5 — NOT for iPhone X!

*2018-02-02, version 1.1*

I love this app, but I can’t use it now that I have an iPhone X. Until they update this don’t try to use this with an iPhone X — you can’t get back out of it.

## Frequently asked questions about JupiterMoons

### What does JupiterMoons do?

JupiterMoons is an astronomy application designed to help users observe Jupiter and its four largest moons: Io, Europa, Ganymede, and Callisto. It allows you to locate these moons at specific dates and times, track transits of the Great Red Spot, and visualize the moons' orbits to scale.

### What are the key features of JupiterMoons?

Key features include the ability to locate and label Jupiter's Galilean moons, accurately time Great Red Spot crossings and moon transits/eclipses, and use time controls to step through seconds, hours, days, or years. Users can also customize their view to match their telescope and access an events calendar with detailed descriptions and images of Jupiter and its moons.

### How much does JupiterMoons cost?

Based on the provided information, JupiterMoons is a paid application. It does not have in-app purchases or advertisements, indicating a one-time purchase model for full access to its features.

### What are the common use cases for JupiterMoons?

This app is ideal for amateur astronomers who want to plan their Jupiter observations, identify its moons, and time significant events like Great Red Spot transits or moon eclipses. It also serves as an educational tool for learning about Jupiter and its fascinating moons with detailed descriptions and images.

### What are the compatibility requirements for JupiterMoons?

The application is designed to work in landscape orientation only to provide the best viewing experience for Jupiter, the Great Red Spot, and the Galilean satellites. Specific operating system or device requirements are not detailed in the provided description.

## Version history (last 3 releases)

### 1.1 — 2016-05-09

This app has been updated by Apple to display the Apple Watch app icon.

- Update to Great Red Spot longitude calculation
- Minor bug fix in the "What's happening with Jupiter” events list 
- Removed cross hairs around Jupiter
- Updated general design

### 1.0.1 — 2013-10-24

Bug fixes for iOS 7

### 1.0 — 2012-11-15

No release notes.

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## More apps by Guidebook Inc

- [SaturnMoons](https://appshunter.io/ios/app/saturnmoons/id606938707)
- [AAS Meetings](https://appshunter.io/ios/app/aas-meetings/id1491066879)

All apps by Guidebook Inc: https://appshunter.io/developer/1387977271

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*