Astro Navigator also only shows a star map of your GPS location... at least it only did last time I tried it and doesn't claim any differently looking at the website. You would swipe to look at the constellations and then look up to find them.
Google Sky Maps not only uses GPS for location but you actually point the phone at the sky and will tell you the stars you are looking at, angle the phone lower or higher and see different stars, when you turn around so does the map. To top it off it's free.
Astro is severely handicapped by comparison in my opinion