Arguably the best star-gazing apps on iTunes, Solar Walk and Star Walk by Vito Technology are now two bucks apiece / €1.89 if you speak Euro.
Solar Walk has been featured by Apple as Best Apps of 2010, 2011, and 2012. As a 3D Solar System model, the app lets you see all the planets in close-up, learn their trajectories, inner structures, history of their exploration, and literally navigate through space and time.
Star Walk is even better, if you’re looking for a larger scale. It’s an interactive astro guide to the night sky which uses augmented reality to follow your movement in real-time and give you a clear picture of the night sky in the exact direction you’re looking.
You can use Star Walk to explore over 200,000 celestial bodies with a wealth of information about stars, constellations, and planets alike.