iPhone: The 13 apps of Christmas

Feeling festive? Then you need's seasonal guide to the best Christmas apps for Apple's iPhone.

First up is the Solar System app, a cosmic take on the advent calendar that lets you journey to the earth's neighboring planets.

Behind each virtual window on the phone is a shot of a different planet, asteroid or moon, all sourced from NASA.

Pictures range from shots taken by space telescopes to photos of various planets' surfaces taken by landers.

Captions by Nick Heath. Image credit: Apple