The image shows William Parsons (1800–67), the third Earl of Rosse, directing the placing of the mirror into an enormous telescope he had had erected at his ancestral home, Birr Castle in western Ireland. The telescope’s 56-foot tube was moved by a system of winches and chains. Light was collected by means of a mirror with a diameter of six foot, which was mounted in a framework built between two stone walls. The sense of expectation felt by Parsons on completion of the telescope was evident in a poem he wrote in the telescope’s honour:

Welcome to thy new existence,
Child of Intellect and Might!
Welcome to the wide Dominions,
Lord of Ether and of Light!
Thou shalt lead us on in triumphs,
Yet to mortal power unknown;
Realms which Angels only visit
Shall yield homage at thy throne.

Very quickly these hopes seemed to be fulfilled, with the first discovery of a spiral nebula confirming that the telescope’s mirror was of the highest quality. Word of the Leviathan spread rapidly through newspapers, guidebooks and lectures, and the enormous telescope seen above all as a technological wonder of a new age. Nevertheless, both the Irish weather and the gradual tarnishing of the mirror meant that the telescope never really lived up to its initial promise.