To paraphrase Carl Sagan's famous remark, there are billions upon billions of stars and other sparkly things out there in the night skies. Gazing into the heavens on a clear night can be a mystical experience, but the real magic occurs when you understand what you're looking at.
Astronomy began thousands of years ago when shepherds in the field gazed up at the sky and saw the outlines of objects and mythical beings traced by patterns of stars. As time passed and technology evolved, our knowledge of the sky improved. But to this day, we still cling to the same 88 constellations envisioned by those ancient shepherds on long ago sleepless nights.
Today, with our improved understanding of the universe, star gazing requires an encyclopedic knowledge of the skies and a library of star charts showing the correct view of the sky based on your current position, time, and date. Lugging around all those references might have been necessary twenty years ago, but modern day astronomer can do it all with an iPad and a few good apps.
This article looks at some of the best astronomy apps available for the iPad. What really impressed me was that, while they all purport to do pretty much the same thing, they offer a variety of different features. If you're looking for one app to get started, try StarWalk from Vito Technologies. If you're a serious star gazer, however, you might want to start with something a little more technical, like SkySafari and add a couple of the others as your needs require.
Viewing a virtual sky
The primary feature of any astronomy app is the virtual sky view. This view shows you the entire night sky, just like you'd see if you were leaning back in your chair in an expensive planetarium. These apps offer a variety of features and functionality, including labeling constellations, cataloguing other objects, and providing vast encyclopedias of background information.
iPad and iPhone/iPod touch: $14.99, app2.me/3070
SkySafari is the most comprehensive astronomy app available for iOS. The app comes chock full of settings that let you focus in on anything from the closest planets to the farthest reaches of space. If you have a computer controlled telescope, you can even connect it to your iOS device and use SkySafari to program the coordinates for your next sky gazing adventure. SkySafari displays the highest level of technical sophistication, which may be a bit much for the average user. Southern Stars, the app's maintenance and support, also offers a Lite version of SkySafari (iPad and iPhone/iPod touch: $2.99, app2.me/3079).
Pocket Universe: Virtual Sky Astronomy for the iPad
This app offers an easy way to view the sky around you and identify the constellations, stars, planets, and other celestial objects. While the view may not be as robust as some of the other apps, it features one of the most organized and easy-to-use user interface/navigation systems. This is a deceptively powerful app that offers some fantastic sky-gazing tools.
Starmap HD offers many technical features of interest to the experienced stargazer. Like SkySafari, it lets you connect to and control a computer controlled telescope. In addition, it offers a variety of charts that detail the times of day when any of the objects in the sky can best be viewed. Toss in a detailed catalogue of stars, planets, asteroids, etc., and you've got an extremely robust app that well serves the novice stargazer and experienced astronomer alike.
Distant Suns 3
Distant Suns 3 was one of my favorites for one simple reason…its spaceflight mode! This lets you leave Earth and view the sky from just about anywhere in space. The app features fantastic animation which actually simulates spaceflight as it whisks you away to the farthest reaches of the solar system. The cool thing about this animation is that it really helps you to visualize the relationship between various objects in the sky. There is even a guided tour of the most visible objects in a particular night's sky. I also loved the tongue-in-cheek approach this app takes to providing information—for example, the "I Believe Pluto Is Still A Planet…" option.
Star Walk for iPad
Star Walk may not be as technically precise as some of the other apps we have looked at in this article, but that really does not matter. If all you are looking for is a map of the sky above your head, then this is the most usable and entertaining app available. This one will display exactly what you see in the sky above your head. As you move, so too does the display on the screen. Just tap the information icon for details on any object in the sky. Otherwise, just sit back, listen to the music (yes, music) and enjoy the show. Who knows, you might learn something, as they say.
Redshift may be well known to PC users, but it's brand new to iOS devices. So new, in fact, that it almost did not make it into this article. I'm glad I had the opportunity to check it out, because this latecomer quickly became one of my favorite astronomy apps on the iPad. It comes complete with a myriad of features. For example, you can view any object in the sky above you from your current location and take a 3-D flight across the universe to get up close and personal with dozens of planets, stars, and other objects. When viewing an object, you can quickly view information about that object or jump to a full Wikipedia article about it. The interface is easy to use and the menus intuitive; this one is both robust and extremely user friendly.
Apps with solar orrery functions
An "orrery" is a mechanical device developed in ancient times to show the relationship between the planets and their moons. The solar orrery, developed in the early 1700's, displays the motion of the planets around the sun. Apps with a solar orrery function display a virtual view of these relationships, just as Galileo must have envisioned it. They also provide you with detailed information about the planets.
Solar Walk – 3D Solar System model
iPad and iPhone/iPod touch: $2.99, app2.me/2555
Solar Walk allows you to view the relative positions and orbits of all the planets in the solar system (though sadly, there is no mention of Pluto). Tap any planet to focus on it and view an orrery of its moons. Tap on the information button to view additional details about the selected planet and its moons. For a real eye-popping experience, grab a pair of 3-D glasses and switch to the app's 3D stereo mode; you'll view the solar system as you've never seen it before.
NASA App HD
While not technically an orrery, we could not discuss astronomy apps without including the NASA app, which is brought to you by the only people who landed on the moon. Tap on any planet in the main screen to view a complete article about it. What's more impressive about this app is the wealth of information it provides about the National Aeronautics and Space Administration, including NASA TV, photos, videos, astronaut biographies, and complete updates on current NASA missions. Pretty much the only things missing from this one was better information about historic NASA missions (Mercury, Gemini, Apollo), and a live NASA radio scanner, which would allow you to listen in on radio transmissions during space missions.
HD Solar System
Like the NASA app, this one is also not technically a solar orrery, but it is probably the most comprehensive overview of the solar system available on the iPad. It provides a detailed look at every object in the solar system, including the so called dwarf planets like Pluto. I was a bit disappointed by the sparse graphics in this app. Solar System XL ($0.99, app2.me/3081) does a much better job with this, featuring eye-popping photographs of every planet, moon, and minor object in the solar system.
Pocket Universe (mentioned earlier) had an excellent virtual sky, but I was not as impressed by its orrery function. It provides a fairly static view and does not allow you to shift the angle or perspective of your view the way other apps do.
Modern, mobile planetariums
Whether you want to learn more about the planets in our immediate vicinity, or the deepest reaches of space, there is a wide variety of apps to help…often with stunning graphics and encyclopedic information. Most of these are available in iPad and iPhone/iPod touch versions, but they really shine on the iPad. These modern, mobile planetariums pack a wealth of information in an entertaining package. That's all for now; I'm off to check out the sky, including all 88 named constellations, the nine planets (go Pluto!), and billions and billions of stars.