Terminal Eleven's SkyView (Android, iOS) gives you a good idea of what to expect for good all-in-one stargazing and sky guide apps. SkyView uses your phone's screen and sensors to give you an augmented reality view of what's up in the sky. Users can turn their smartphones and tablets into AR viewfinders for identifying stars, planets and constellations; the app can display an object's track in the sky as well as information on select objects, planets, and satellites. SkyView also includes a "time travel" feature that allows you to view the sky as it would have appeared in the past, or will appear in the future, based on what we know of each object's movements.
Night Sky on iOS is another gorgeous app that takes full advantage of iOS 11 to deliver a really nice-looking augmented reality sky map. Users can view thousands of stars, satellites, planets and constellations; Night Sky takes things further with Apple Watch support that brings the sky map down to your wrist. Users can hold up the Apple Watch to identify objects in the sky, or look down to view a "celestial compass" that gives an overview of objects visible tonight. A new addition with the introduction of iOS 11's ARKit is the AR Grand Orrery that displays a virtual model of the solar system that you can circle around and view. A free Android version, Night Sky Lite, is available for mobile users on that platform.
Pocket Universe is another great all-in-one sky watching app that provides both a portable sky map as well as a wealth of extras like augmented reality modes. Users can view a map of the sky above, complete with labels and constellations, as well as track individual objects and planets (with a "show me" mode to guide your aim). An augmented reality orrery lets you view the solar system in your own living room, and the app includes extra activities and resources like quizzes and Wikipedia links to various objects.
Formerly a Google project that's gone open source, Sky Map is a neat augmented reality app that turns your smartphone or tablet into a mobile planetarium. Sky Map uses your phone's many sensors to calculate your geographical position and then display a detailed star map based on where your device is pointed. The map includes the constellations, the names of stars and planets, and makes for a great companion app for stargazers. A night mode ensures your low light vision doesn't get ruined, and a time travel feature lets you view the sky as it looked in the past, or as it will be in the future.
Vito Technologies' Star Walk 2 (Android, iOS) is an augmented reality star chart that displays the stars and planets in the heavens above you. In addition, the app includes detailed information on the history and mythology of the various constellations, stars and planets, as well as a coordinates viewer for easy reference. A Time Machine slider lets you view the skies of the past or the future, and you can tap on individual objects for more details. A night mode allows you to stargaze without burning out your night vision, and an augmented reality view overlays the star chart over your camera view.
Rather than a virtual planetarium, Solar Walk 2 (iOS) is a pocket orrery, modelling the position of the sun, planets, moons and other assorted celestial objects in our solar system. Lavishly animated and illustrated, users can zoom in on each of the planets, moons and even a number of space craft and satellites to view stunning images, infographics, and detailed writeups of each object. You can also zoom out and view the entire solar system in motion, the app modelling each celestial body's movements over time. The older Solar Walk app is also available on Android devices.
Stellarium has long been a well-regarded open-source planetarium app on desktop devices, and it also has a paid mobile version on Android and iOS for those times when you want to take your sky guide with you when stargazing. The app features a catalogue of more than 600,000 stars on a zoomable map that can also be used as a viewfinder and star or satellite identifier by pointing your phone up at the night sky. Users can display asterisms and constellations from different cultures, as well as search for artificial satellites.