The United Nations declared 2009 the International Year of Astronomy to celebrate the 400th anniversary of the first astronomical observation through a telescope by Galileo Galilei in 1609. The global celebration will highlight the multi-disciplinary contributions of astronomy in the journey of humanity and focus on the relationship between science and faith today. One of the goals of the International Year of Astronomy is to help the citizens of the world rediscover their place in the Universe through the day- and night-time sky, and thereby engage a personal sense of wonder and discovery. The International Year also offers a unique opportunity to highlight the extraordinary discoveries in astronomy over the last 400 years, and especially in recent years, while also promoting the essential role astronomy plays in science education. The Philatelic and Numismatic Office has produced two stamps showing two oil paintings by Donato Creti - Saturn and The Sun. The 18th century works from the Pinacoteca of the Vatican Museums are an eight-part series of small format paintings (50 x 35 cm) called “Astronomical Observations”.