The invention of photography provided a huge opportunity for Victorian astronomers. Deep space objects- too faint to be seen by looking through a telescope- could now be revealed on a photographic plate, provided the exposure was long enough.

The problem was movement of the earth during the time it took to take the shot, which left the image blurred and unrecognisable. Isaac Roberts solved that by developing a telescope and camera combination that would accurately track the subject for long enough to record a clear image.

It was heady stuff, opening up new stars for inspection that had never been closely examined before. Roberts successfully produced the first detailed pictures of the Andromeda nebula, more than 2 million light years from earth, revealing its hitherto unseen spiral structure.

Like John Jones – the “workingman astronomer” of Bangor- Roberts was an amateur, though unlike Jones he had personal wealth to fund his hobby. Born at Groes near Denbigh he had owned a successful building firm on Merseyside before retiring to pursue his primary interest in astronomy.

In the garden of the house he called “Starfield” be build an observatory good enough to be the envy of many a leading institution. He published several acclaimed books of his photographs and enjoyed international recognition. Among numerous honours was the Gold Medal or the Royal Astronomical Society as well as his F.R.S.

At the age of 67 he married Dorothea Klumpke, an American astronomer nearly three decades his junior who later won considerable recognition in her own right. He continued to benefit the study of science in Wales after his death with large endowments to the University Colleges at Cardiff and Bangor.

A crater on the far side of the moon is named Roberts in honour of Isaac, along with his South African fellow astronomer Alexander.