A successful builder by day and traversing the sky by night, Isaac Roberts took the first clear photograph of Andromeda, the closest galaxy to our Milky Way.

Mr Roberts, born in 1829 and the son of a farmer at Groes-bach Farm near Denbigh, took the photograph in 1888, revealing its distinctive spiral structure and mysterious dark lines to a doubting world.

He worked as a builder in Liverpool, having moved there aged seven, then spent the latter part of his life as a neighbour of Sir Arthur Conan Doyle at Crowborough in Sussex.

But his telescope revealed far more mysteries than Sherlock Holmes could ever have dreamt.