SkySafari 3 price dropThis may only be the basic version of the more expensive Sky Safari series, but there is more than enough to explore, with 120,000 stars, 220 star clusters and other celestial objects available in the app, plus descriptions from professional astronomers.

You can view the sky from any place on earth at any time up to 100 years into the past or future and use the gyroscope in your iPhone to help identify stars and planets from a particular viewpoint.

Normally 59p (99c), this version is currently available for free from iTunes here. Download it and then decide whether you’d like the full version or indeed to try the wonderful, SkyView, a former Follow That App of the Week.