In this short series there is another chance to see some of the world's finest observatories at work, visited by Patrick Moore for The Sky at Night.
Mauna Kea - Half-way to Space
Mauna Kea, in the Hawaiian Islands, is almost 14,000 feet high. At its summit the air is thin, and the skies are clear - which is why some of the world's largest telescopes have been set up there.
Patrick Moore visits this picturesque observatory and talks about its achievements with the astronomers who are living and working there. Producer PIETER MORPURGO (R)