Reach for the stars – An Irishman’s Diary on Ireland’s observatories

For more than two centuries, Ireland has had observatories closely watching the night sky.

The first was Dunsink in Castleknock, Dublin, opened in 1785. It was where Sir William Rowan Hamilton, one of Ireland’s foremost mathematicians and astronomers, professor of astronomy at Trinity College and Ireland’s Royal Astronomer, lived and worked. It was also the place where the time standard for Ireland was set until 1916.

Originally, Dunsink was part of Trinity College Dublin, but it was bought for the State in 1947 and is now part of the Dublin Institute for Advanced Studies.

It has free open nights through the winter; if the skies are clear, visitors can see many celestial sights through the historic Grubb telescope.


Armagh Observatory is four years younger than Dunsink and it is a modern research institute with some 25 astronomers; the surrounding Astropark’s attractions include scale-models of the solar system.

During the 19th century, two of the key observatories in Ireland were run by talented amateurs. In 1830, Col Edward Joshua Cooper set up an observatory at Markree Castle, just south of Sligo. For several years, it had the largest telescope in the world, which in the late 1930s ended up in a Jesuit seminary in Hong Kong. The castle is now a luxury hotel.

In the 1840s, the third Earl of Rosse built a huge telescope in the grounds of Birr Castle in Co Offaly. It enabled his lordship to see further into space than anyone had previously managed and one of his major discoveries was the spiral nature of some nebulas, today known to be spiral galaxies. Today, Birr Castle has an interactive science centre, where people can see 19th-century astronomical equipment.

The tradition of amateur observatories continues strongly to the present day.

The last observatory set up in 19th-century Ireland was the Crawford Observatory at University College, Cork, which dates from 1880.

More recent times this century have seen a second observatory in Cork. The observatory at the historic Blackrock Castle was set up in 2007, as part of the Cork Institute of Technology. The castle also has two planetariums, which put on many live shows for around 60,000 visitors a year. They can even send an email to the International Space Station.

Also in Co Cork, Schull has a planetarium, which was opened in 1989, thanks to the generosity of a German industrialist, Josef Menke, and his family.

The newest planetarium, together with a maritime museum, is in the old coastguard station at Greencastle on the Inishowen peninsula in Co Donegal; it opened in 1994.

Clair McSweeney, centre manager at Blackrock Castle observatory and planetarium, says that we have a very deep astronomical heritage in Ireland, one that is very easy to tap into.

She adds: “Astronomy is one of the most inclusive and beautiful of sciences and it’s our job to unlock it”.

Ireland also once had a great reputation for making astronomical telescopes.

Thomas Grubb was a Quaker from Co Waterford, a self-taught mechanic with a great interest in astronomy; he started making telescopes at his first factory and observatory, beside Charlemont Bridge on the Grand Canal in Dublin. In the mid-1860s, when the Grubb firm won an order for a colossal telescope for Melbourne Observatory, it had to move to a new and larger factory nearby, in what is now Observatory Lane in Rathmines.

The Grubb firm moved to England during the first World War, so the name of Observatory Lane is the only remnant of Dublin’s one-time astronomical telescope maker. The firm then went into liquidation but was revived by Sir Charles Parsons, youngest son of the third Earl of Rosse, surviving until 1985.

Given the scale and depth of Ireland’s astronomical heritage, it’s hardly surprising that Astronomy Ireland claims to be the most popular astronomy club in the world.

There’s just one cloud on the horizon: worsening light pollution, a growing problem in many parts of the world. A mere 5 per cent of the country now has pristine night skies, unpolluted by artificial light. The aggregated lights of Dublin are now so so bright that they can be seen from space. For people living in urban areas, the night skies are so blocked off by lights that the stars are barely visible.