150-year-old telescope sees again

150-year-old telescope sees again

Keywords: Canning, Plating, UCL

Wm Canning has helped restore a historic 150-year-old telescope - with a product usually used only in highly corrosive environments.

The chemical company's NimaxTM electroless nickel plating product - normally found protecting North Sea oil and gas equipment - has been used to coat the mirror.

Despite the normally hostile environment in which Nimax HCR is used, plating company Nitec (Derbyshire) Ltd thought it would be ideal for coating the telescope's mirror.

Wm Canning's Mike Burns, who was responsible for overseeing the project,said: "I wasn't convinced that the job could be done, but Nitec insisted it could and said they were going to use Nimax HCR.

"I was there during the three-hour preparation process, and for the start of the ten-hour plating operation. Everything went according to plan, and the product did a superb job."

Nitec managing director David Brown said: "It was not a straightforward job. It was quite a responsibility lifting, plating and then inspecting a mirror that measured 6ft across and 8in thick.

"Because the mirror substrate is aluminium, we thought Nimax HCR would be ideal. It offers a less stressed deposit than other electroless nickels, and is therefore easier to polish to a mirror finish. It certainly did a beautiful job."

Coated with a layer of nickel, the mirror has been polished to a brilliant optical finish at the Optical Science Laboratory at University College, London(Plate 7).

 Plate 7 In reflective mood: David Brooks, at the Optical Science Laboratory, University College, London where he has been working on the world's first large aluminium mirror for use in an astronomical telescope

Dr David Walker, head of the laboratory, said: "This is pushing back the boundaries of technology. Compared to a traditional glass mirror the cost benefits of this manufacturing route are enormous, and therefore we had to try".

The mirror will be taken to Ireland in the spring, where it will be reunited with the rest of the telescope and demonstrate the new mirror technology in operation. It will be the first time for 80 years that the telescope has worked.

Built by the Earl of Rosse, in Ireland, in 1848, the telescope used to be the largest in the world, and was dubbed "The Leviathan".

Details from Wm Canning Ltd. Tel: +44 (0) 121 606 8291.