Skip to content

By Alison Boyle on

When Irish Skies Are Smiling

As today is St Patrick’s Day and I’m of the Paddy persuasion myself, here are a few objects with Irish links in our astronomy collection.

The original orrery c. 1712, made for the Earl of Orrery by John Rowley, London copied from a planetarium model made by George Graham.

This is one of the earliest mechanical models of the Solar System, on display in Science in the 18th Century. It was made for the 4th Earl of Orrery, Charles Boyle. His County Cork title gave its name to subsequent planetary models.

Another Irish peer with a keen interest in astronomy was William Parsons, the 3rd Earl of Rosse.  He built several telescopes at his castle in County Offaly. The largest, known as the Leviathan of Parsonstown, was the world’s biggest telescope for over 70 years. You can see its six-foot  mirror in Cosmos & Culture, or visit the reconstructed telescope at Birr Castle.

Scale model (1:24) of the Great Rosse Telescope with a six foot speculum mirror, built by the Third Earl of Rosse in 1844-45 at Birr, Ireland.

There’s one big snag with building a telescope in Ireland – rain. Lots of it. Many of Lord Rosse’s visitors moaned about ruined observing nights. But during some rare breaks in the clouds, Rosse was able to observe nebulae, hazy patches of sky that had been puzzling astronomers for years. Thanks to the great mirror’s light-gathering power, he could see that some had spiral structures. We now know they are galaxies beyond our own. (Today, ‘nebula’ has a different meaning in astronomy).

Another telescope used to study nebulae was Isaac Roberts’ twin equatorial telescope. Its 20-inch reflecting telescope and stand were made by Grubb of Dublin.

“Twin Equatorial” Telescope, 1885. Made by Sir Howard Grubb for Dr. Isaac Roberts, F.R.S.,

And finally, since it’s customary to celebrate Paddy’s Day with a drop of the black stuff, here’s a  photo of the black drop effect. Sláinte!

The black drop effect is sometimes seen when Venus transits the Sun. (Statis Kalyvas and VT-2004, used with permission)

One comment on “When Irish Skies Are Smiling

  1. Very interesting and appropriate for the day that’s in it.
    Of course, my own interest is not altogether of the scientific kind…………. the royal connection, don’t ya know , would be of much more interest !!

Comments are closed.