Francis Andrews of Trinity College Dublin leaves £3,000 in his will for the construction of an Observatory at Dunsink.
Dunsink Observatory opens with Rev. Henry Ussher as Director.
The Observatory is placed under the management of the Royal Astronomer of Ireland.
Rev. John Brinkley takes over as director and records his work on the transits of stars in five large leather bound books.
William R. Hamilton is appointed as the Andrews professor of astronomy in Trinity and becomes director of Dunsink before he has even completed his undergraduate degree in maths and classics.
William Wordsworth first visits Hamilton and his sisters at Dunsink.
On a walk from Dunsink along the canal into town Hamilton has a flash of inspiration and carves his Quaternion equation into Broombridge.
12″ lens is donated to Dunsink by Sir James South.
Grubb builds the South Dome Telescope to mount the South lens.
Robert Ball becomes Director of the observatory, he completed research on Screw Theory.
Dunsink provides the official time for Ireland (Dublin Standard Time).
Ireland moves from DST to GMT, however Dunsink Observatory is still used to maintain accurate clocks throughout the city.
Eclipse expedition to Sobral proves Einstein’s Theory of Relativity with the Grubb coelostat.
Eamon de Valera founds DIAS, it is the second institute of advanced studies in the world after Princeton, USA.
de Valera sets up the School of Cosmic Physics in DIAS and acquires Dunsink Observatory from Trinity.
The ADH (Armagh-Dunsink-Harvard) telescope is built by Perkin Elmer Corporation.
Ellison becomes director of the Observatory and Dunsink becomes a world renowned solar physics research centre.
The Meridian room burns down and a piece of moon rock is lost to the Finglas dump.
Patrick Wayman publishes his history of Dunsink Observatory.
Peter T. Gallagher appointed Director.