Recent reports in the media about a new radio telescope in the grounds Birr Castle has firmly shone a spotlight on the astronomical heritage of Ireland. From 1845 until 1914 the largest telescope in the world stood in the grounds of Birr Castle. It was the brainchild of the 3rd Earl of Rosse and through it he made many wonderful discoveries, he named the Crab nebula and was the first to document the structure of spiral galaxies, although at the time, they didn’t truly understand their nature.