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.
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JupiterMoons FAQ
Is JupiterMoons free?
Yes, JupiterMoons is completely free and it doesn't have any in-app purchases or subscriptions.
Is JupiterMoons legit?
🤔 The JupiterMoons app's quality is mixed. Some users are satisfied, while others report issues. Consider reading individual reviews for more context.
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.
Wide Angle needs to be wider
The only knock on this app is that the wide-angle view does not allow sufficient room for Callisto much of the time.
Decent - needs date/time control
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.
NOT for iPhone X!
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.
Bad data
This app often has bad data concerning multi moon transits and moon shadow transits.
Date Option
I've been using the on-line version for years and a bit disappointed we are nickel and dimed into paying for this. One glaring omission is an option to enter another time or date manually, instead of tapping, tapping at minute and hour intervals to get other dates and times.
Very Useful
Last night this app proved to be very effective. I was viewing a shadow transit across Jupiter when I spotted what I suspected was the GRS, so I then opened the Jupiter's Moons App and it immediately confirmed my sighting.
Almost perfect!
The only thing this app is missing is the info telling you when Jupiter rises & sets for your location.
Great little app.
I only wish it had one more zoom level. Sometimes the transiting shadow is too small to see on my iPhone screen.
Very thin application
This app is disappointing in how little it does. Besides the main display of Jupiter and its four visible moons' positions, it has very brief descriptions and a few photos of the planet and the four moons. It is far from a complete reference on Jupiter. For example, it mentions the fact that Jupiter has more than 60 moons, but contains no other information about them.
Compared to other full featured astronomy apps like Star Walk, Safari Pro, or Luminos, each of which costs only a few dollars more, this app delivers very little for the money.