JupiterMoons

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

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.

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.

This is a simple app that does one thing well: it shows and tells you when Jupiter's four Galilean moons and their shadows will be moving across Jupiter's face, when the moons will be passing behind Jupiter or through Jupiter's shadow, and when the Great Red Spot will be in the middle of Jupiter as seen from Earth, and thus most easily visible through a telescope. I've been using the tables in Sky and Telescope Magazine to plan when to see Galilean moon transits, but this app makes it much easier and quicker -- you don't have to scan through a long table of fine print and mentally translate from Universal Time to your local time zone. It's all right on the screen with a clear diagram of what everything will look like through your telescope, and you can adjust the display to show an inverted or mirror image, to match the view through your instrument. The supplemental information and images of Jupiter and the moons are well chosen and helpful, but the main screen is the reason to get this app. As other reviewers have said, it would be nice to be able to set parameters for alerts, e.g. a shadow transit or occultation between 7 pm and 11 pm local time. Another quibble: this app only displays in landscape mode, which makes sense to get the widest diagram of Jupiter and the moons, but I would like to be able to shift into portrait mode because that's how I hold my ipad when I'm at the telescope.

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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.