This set is one of two proof sets issued by the Royal Australian Mint to mark the International Year of Astronomy. A total of 9 599 2-coin proof sets were issued. The two coins in the set are:

• International Year of Astronomy Twenty Cents
• Mob of Kangaroos Dollar

The coins are housed sealed in a black plastic folder accompanied by an information sheet and protected by colourful presentation box.

This set includes a special twenty cent coin depicting a family gazing through binoculars and telescope at the night sky