William Parsons, Third Earl of Rosse and the astronomer who built the Leviathan of Parsonstown.

Birr in County Offaly was once known as Parsonstown after the Parson family who lived at Birr Castle. Among them was astronomer William Parsons, the third Earl of Rosse.

In 1845, William Parsons had the Leviathan of Parsonstown built at Birr Castle. The telescope has a mirror of 72 inches in diameter, larger and more powerful than anything built before. This was a reflecting telescope which uses a mirror rather than a lens.

It made use of a mirror, not a lens.

William Parsons, Third Earl of Rosse
William Parsons, Third Earl of Rosse

One of the biggest challenges in the construction of the telescope was the size. William Parsons was confident that it could be done despite the fact that making big mirrors at this time was not easy. Among those sceptical of the plan was Rev Robinson director of the observatory at Armagh.

Were there a limit to scientific discovery and we had reached that limit, we should be in the condition of a man who with the most splendid landscape before him was insensible of its beauty because the charm of novelty had passed away. Each successive discovery as it brings us nearer to first principles opens out to our view a new and more splendid prospect.

Rev Robinson was surprised by the strange, unknown world he saw when he looked through the Earl of Rosse's telescope.

This excerpt from the programme features Conor Evans as the Earl of Rosse and Chris Curran as Rev Robinson.

This episode of 'Irish Men and Irish Women' was broadcast on 15 December 1976. The presenter is Ronnie Drew.