By Pete Williamson

Whilst on tour of Ireland in the summer of 2019, delivering outreach talks and workshops, I thought it would be a lovely touch to visit Birr Castle and Gardens which is the home of The Leviathan. This is the large telescope built in 1844 by the 3rd Earl of Rosse, William Parsons. The telescope was for many years the world’s largest operational astronomical telescope, as it housed a 72” mirror – not made of glass but a highly polished metal called speculum. The telescope was famous for being used to see structure in Messier 51 (The Whirlpool Galaxy), and many of the original drawings are on show.

My approach was to use FTN to image M51 and then process the data whilst stood alongside the Birr telescope, and on completing this I was immediately able to compare the result with the original drawings made by William Parsons. I felt somewhat emotional as I seemed to touch history by doing this, and it really made me think of William who would have been stood at the telescope back in the 1845.

The telescopes (Leviathan and FTN) are both of similar aperture but the speculum mirror would not have the same level of light grasp (i.e. it just wasn’t as reflective) – but having said, that the drawings are quite detailed and a brilliant record of what was seen by eye”.

You can find out more about creating amazing images of M51, and other “classic” targets, by visiting our educational resources here.