iPhone astronomy apps have come a long way over the years. You can now use them with augmented reality to find out what you are looking at in the sky. Take Stellar Tour for instance: it is a cool little app that you can rely on to learn more about the stars, constellations, exoplanet systems, galaxies, and moons.
To get started, simply point your device towards the night sky to start learning. Stellar Tour displays exoplanet systems in their actual location. It also provides you with sizes, temperatures, and orbits of the known exoplanets. Images uses are from NASA, JPL, and other reputable sources.[where to find it]