Discover the cosmos - The Washington Post (itunes.apple.com) - Planet app from iTunes store. Are your eyes to the sky? For astronomy enthusiasts - or those cultivating a love of the really great outdoors - there are plenty of apps that let you pursue your cosmic hobby. One option is Planets, which lets you explore the sky either by scrolling around with your finger or pointing your phone at sections of the sky you want to explore more deeply. You can use the app to check out individual planets (and Earth's moon) one at a time. Free, for Android and iOS devices.