Vatican City, 30 October (AKI) - The Vatican and its scientific observatory are organising a celebration at the Vatican City on Friday and Saturday. The event coincides with the International Year of Astronomy, which will close on 9-10 January in the northern Italian city of Padova.

The two-day Vatican celebration includes an address at the Pontifical Academy of Sciences by Prof. John Huchra of the Harvard-Smithsonian Centre for Astrophysics and President of the American Astronomical Society with the title "From Galileo to Hubble: Astronomy in the 21st Century".

The programme will also include a tour of the Tower of the Winds at the Vatican. Built in 1582 at the time of the Gregorian Reform of the Calendar, the tower was the first location of the Vatican Observatory.

A visit to the Vatican Secret Archives, Michelangelo's Sistine Chapel, and the ASTRUM 2009 exhibition at the Vatican Museums also feature in the celebration.

On display in this exhibition there are 130 items, including astronomer Galileo Galilei's original handwritten notes detailing his observations of the moon, as well as his publication "Starry Messenger" from 1610.

The Catholic church once branded Galilei and philosopher Giordano Bruno 'heretics' for their views on astronomy.

The highlight of the day is a private audience with Pope Benedict XVI who will address an international group of renowned astronomers.

A tour of the new headquarters of the Vatican Observatory in the Vatican Gardens at the pope's summer residence Castel Gandolfo is planned on Saturday.

Pope Benedict XVI officially inaugurated the Vatican Observatory's new headquarters on 16 September because the previous observatory's premises needed to be used to receive heads of state and diplomats visiting Benedict.

A second Vatican observatory already exists in the US state of Arizona at the summit of Mount Graham which is also considered a sacred place for native American Indians.