From the publisher web site:

The Cosmic Decoders Leader Kit is the fourth release in our series of family events and activities on topics in astronomy for Family ASTRO Event Leaders. It focuses on how astronomers "decode" light from space to learn about the universe and how we might decode radio waves from possible alien civilizations out there. The Cosmic Decoders Card Set (the corresponding Take-Home Activity) consists of a deck of 72 cards featuring beautiful color images of cosmic objects and some well-known telescopes. These can be used to play four different fun astronomical games.