The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Elijah Hibit:
For someone who is beginning to explore the universe, this app is indispensable. Included are pictures of the planets as well as a flash card review of the planets and their names. This is for the beginner astronomer to become familiar with what each of the planets look like. Obviously, the planets are not presented to scale. As we look up to the massive universe outside our Earth, it can be a daunting thing. Understanding the planets in our very small solar system is the first step.