Holding together the world’s largest telescope 04 September 2020

BUMAX has been chosen to supply thousands of high strength and corrosion resistant fasteners for the ELT, Extremely Large Telescope, currently under construction in the Netherlands.

The €1 billion ELT will be the world’s largest telescope when it becomes operational in northern Chile in 2024. It is a reflector telescope, collecting universal light using a massive curved mirror that is 39m across – 3 times the area of the next largest telescope.

The giant mirror will consist of 798 individual hexagonal segments each measuring 1.4m across and will be driven by electrical motors for fine-tuning. An additional 133 segments have also been made for a continuous swapping process, which will allow the ELT to stay operational whilst the mirrors are coated and cleaned. The segments will work together as a single mirror to collect 100 million times more light than the human eye.

BUMAX® fasteners are being used to fix the individual telescope mirrors to the segment supports. Twelve 10mm BUMAX 109 M6 bolts are used on each of the 931 segments.

Customised bolts require special tools
The ELT is presently under construction by Dutch company VDL ETG Projects. Michael Evers, project manager at VDL ETG, said: “Standard stainless steel bolts lack the strength required. We required a 10.9 strength bolt, and with the corrosion resistance of stainless steel. BUMAX offered us the perfect solution. The high strength BUMAX 109 fasteners prevent damage to the mirror segments, which is very costly. Their corrosion resistance is also essential as the fasteners are sometimes open to the elements and will reduce future maintenance requirements.”

The bolts are a customised product that have been coated with a special surface treatment and require special tools to manufacture.

“This order is yet another testament to BUMAX being able to provide the very best fasteners for the most demanding applications. We have also been trusted with supplying fasteners for the CERN accelerator in Switzerland, as well as satellites, and submarines,” explained Patrik Lundström Törnquist, managing director at BUMAX.

Deputy Editor

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

Biog

Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.