Judging from the reviews in the App Store I am not the first to be enchanted by Sky View, the augmented reality astronomy app. When I point my phone camera at the night sky this app displays the heavens, as if through a window, overlaid with the specks of stars, at appropriately varying brightness. (The phone’s sensors tell the program which way it is pointed, and computes the simulation on screen.)
It also shows planets and satellites in the proper place in the sky. Tap a celestial object, and its name appears, just where the object is in the sky covered by your screen. The effect gives the impression the annotation is happening on the sky itself. It’s quite magical and couldn’t be easier to use. The paths of the planets are traceable as a thick yellow line, and as your finger slides along the line, you can see the times when the planet will arrive at this point in the sky. Constellations appear as ghostly outlines, good for learning. Recently Sky View has been especially fun, with Mercury, Jupiter, and Venus all visible on the western horizon around sunset, and Mars rising overhead at night.