The Night Sky from iCandiApps is a stargazing app for the iPad, iPhone, and iPod touch. You point your iOS device skyward, and see a real-time, geolocated display of the heavenly bodies overhead--stars, constellations, planets, satellites, and galaxies.
Move your device around, and you can explore what ever celestial stuff should be right above you. Of course, if you're using the app during the daytime, Night Sky will show you objects you might expect to see come nightfall; it's awfully hard to spot Mars when the sun is shining bright.
By default, the app includes a goofy space-age soundtrack; you can disable it. You can't control which space objects the app displays with a sole exception: Satellites aren't displayed unless you manually toggle them on.
There's also an option to display a 3D model of the planet I suspect most of Macworld's readership calls home. Looking at the globe lets you see precisely where Night Sky has pinpointed your location. You can also toggle satellites in this view, and observe how there are just oodles of them surrounding Earth.
But what the heck are they? Night Sky won't tell you. Night Sky disappointingly won't tell you much at all, other than that whatever objects it identifies out in space are there. You can't find out anything about those satellites--or about the planets, stars, or anything else.
Were Night Sky the only app capable of doing what it does in the App Store, it would be magical - a pocket guide for the amateur astronomer to understand what you're looking at. But with apps like Solar Walk and Pocket Universe out there, replete as they are with tremendously better visuals and a world of extra details, the only reason to choose Night Sky is if you're on an exceedingly tight budget, either in terms of dollars or storage space left on your iOS device. (Because Night Sky offers much less detail than those other apps, it's also a much smaller download.)
Night Sky is fine, and it does what it does well. But barring one of those just-mentioned constraints, you'll better satisfy the scientist inside you with a more feature-rich app for studying the nighttime sky.