Jupiter reigns big and beautiful over December's sky. Now you can take our newest app with you as your guide to Jupiter's moons, Great Red Spot, and more.

This December is the month of Jupiter. The king of planets came to opposition on December 2nd, rising around sunset and setting around sunrise. As the month goes on, Jupiter stays nearly as big and beautiful as it was that night, but rises earlier every evening. The gas giant shines with a magnitude around -2.3 for most of the month, especially bright since this is one of the closest oppositions during Jupiter's 12-year orbit.

Many of our readers have found our Jupiter's Moons and Jupiter's Red Spot Javascript utilities useful when planning a nights' observing. Now we have something even better.

JupiterMoons is our newest iPhone/iPad app developed by our friends Tim DeBenedictus and Bill Tschumy at SouthernStars, based on some of our site's most popular utilities. The app is available on the iTunes store for $2.99.

Download on the App Store

JupiterMoons guides you around Jupiter, showing the location of Io, Europa, Ganymede, Callisto, and the Great Red Spot at any date and time. You can zoom in for a better view of a Great Red Spot transit, zoom out for a full view of the moon's orbits, or adjust the view to what you're seeing through the telescope with a few clicks. The time control settings make it easy to look up information for next week or next month. Or have some fun — speed through the months to watch Jupiter change size as it approaches opposition or conjunction.

JupiterMoons main screen

Special events, such as moon transits and eclipses and Great Red Spot crossings, are called out in a separate box. Clicking on any of these events will open them up in the main window. In addition, the app contains encyclopedic entries about Jupiter and its ice-and-fire moons, written by contributing editor Kelly Beatty and accompanied by stunning photos.

JupiterMoons encyclopedia

JupiterMoons is for Apple devices only right now. Note that this app 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.

In addition to our app, we have a number of Jupiter observing tools and guides on our site. Here are a few of them:


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December 14, 2012 at 12:44 pm

It's really great that people are creating apps to aid us in learning about the universe, but many (most?) of us cannot afford an i-device, and have Android-based toys. Sure would be nice if those who create apps could also prepare Android compatible versions.

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Monica Young

December 14, 2012 at 12:50 pm

As much as we'd like to develop for Android as well, that would mean twice the cost of development. For a small outfit like us, developing each app twice isn't economically feasible. We chose to go with Apple devices because the vast majority of our SkyWeek app downloads come from Apples, not Droids. Thanks for your interest though, and hopefully we'll be able to make Android-based apps in the future.

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December 14, 2012 at 1:05 pm

I recently read that 40% of smartphone and tablet devices are Apple and 60% are Android. Regardless whether those figures are accurate, there are a number of us Android device users who would enjoy using these new apps.

There is still no updated version of Sky Week for Android and now it sounds like there is no intention of developing the Jupiter app for Android.

I'm considering not renewing my Sky and Telescope subscription if software developers like you refuse to provide Android users the same apps as Apple users.

I would be willing to pay a small charge for an Android version of these apps. Is that a possibility ?

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James Lummel

December 14, 2012 at 1:08 pm

There's a Sky Week Android app?? Where?


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Monica Young

December 14, 2012 at 1:14 pm

James, you can find SkyWeek for Droids here: https://play.google.com/store/apps/details?id=com.skyandtelescope.skyweek12

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December 14, 2012 at 7:05 pm

I agree with Ken and Tim. I choose not use apple apps or products based on my personal moral beliefs. I wish you success in your endeavors, and would purchase such an aid to my observatory, but you choose to exclude my business by supporting only one business model. No judgement of others here, just offering information relating to purchasing decision making process.

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December 15, 2012 at 12:27 am

I'm sorta with Ken and Tim and James. Apple stuff is flashy and popular. A lot of us don't like paying for flash or are not interested in keeping up with what's trendy. Some solid 'droid apps would be much appreciated.

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December 15, 2012 at 7:48 am

As an Android phone user, I'm quite deluded by the lack of consideration for non I-whatever users.

Considering Apples doesn't rule any more the market of tablets and phones, it could be reasonable to support Android rather than Apple if lack of budget doesn't permit supporting both...

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Kevin Stanley

December 15, 2012 at 9:39 am

I'll add my vote, too. Please reconsider the apple-only development model. Apple tries hard enough to be a monopoly without sky and telescope's help. I can afford an Android tablet but not an iPad. Many others are in the same position.

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December 16, 2012 at 1:11 pm

As someone who appreciates quality and is willing to pay for it, I understand why you focus on iOS apps.

Thank you. And keep up the good work.

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Peter H

December 17, 2012 at 6:56 am

It is clear from the earlier posts that in neglecting Android apps you are antagonising a significant proportion of your customers.
It is also inconsistent, because your seven-decade DVD collection cannot be used on iPads (what a pity you didn't make that in PDF format - I know I'd use mine a lot more if I could read it on an iPad).
And it's all unnecessary. It is now possible to develop cross-platform apps in Java that will run on iOS and Android (see for example http://www.oracle.com/technetwork/developer-tools/adf/overview/adf-mobile-096323.html.
I suggest you talk with your software developers and drive a better deal from them.

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December 19, 2012 at 6:47 pm

While I do use android devices, I do realize that they are harder to developed for. Apps on iOS only have to be tested with a half dozen devices, while Android is thousands. We have to be objective in this. If you chose Android you are sacrificing app development time for software flexibility.

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Gary P

December 21, 2012 at 2:05 pm

It seems to me that since the design and program logic have already been developed, programming for the Android would be less expensive, and it might be easier to recoup the development costs.

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