Wales in North America Blog

Making Prototype Mirrors in Wales for the World’s Largest Telescope

Posted by Caroline Gray on Feb 23, 2015 9:28:00 AMGlyndŵr University in Wales is working on a ground breaking scientific project involving the world’s most powerful telescope.

What is the E-ELT or the ESO Extremely Large Telescope?

The E-ELT, the largest ever ground based telescope, is currently being built by the European Southern Observatory (ESO). This is a ground breaking scientific project, it will require, bigger, more accurate, more stable and faster data processing than has ever been achieved.


What makes this telescope different? What will it tell us?

It is bigger, so big it will gather more light than all the existing 8-10m class telescopes on the planet to date….. In simple terms this means improved signal to noise ratio which leads to improved resolution.


The E-ELT telescope is expected to provide answers to some of the most prominent open questions in astrophysics today. Such as…


Are we alone?

Do exoplanets (An exoplanet or extrasolar planet is a planet that does not orbit our Sun and instead orbits a remote star) exhibit living earth like signatures?

The E-ELT will have the resolution to deliver some of the first images of, analyse their atmospheres and deliver important information on the structure of these potential life sources..

The telescope will enable scientists to question some of the fundamental laws of physics…The telescope

Were physical constants really constant throughout the history of the Universe?


What really happened at the big bang?

The telescope offers the opportunity to challenge the very root of our understanding of the Universe since the Big Bang!

The telescope will enable astronomers to challenge, interrogate and develop our understanding of Stars, Galaxies and the Universe as a whole since the beginning of time….

So a truly ground breaking scientific tool has been made possible by the coming together and financing by 16 nations to a budget of €1.1B. This money is intended to be returned to the member states through contract awards for the construction. And this is where Glyndwr University comes in…

One of the challenges (there are many!) when considering the building of the E-ELT telescope is the production of the 39m primary mirror. This mirror will be constructed from 798 hexagonal mirrors. Each mirror will be 1.45m corner to corner and ~50mm thick. Each of these mirrors is required to align with its neighbour to produce an f/0.88 continuous mirror surface with a 39m diameter.

In order to do this the level of accuracy and repeatability of the mirror processing and testing required is unprecedented. Typical industry lead times for optics of this size are of the order of 20 weeks. Therefore to produce this volume of mirrors in the time frame of the telescope build ESO have set the industry a challenge.  Better, faster, cheaper… a common goal of modern manufacturing.

In order to explore the feasibility of serial manufacture on this scale, in 2008 ESO awarded two prototype segment contracts one to an existing large optics supplier (SAGEM in France) and one to an ambitious group of scientists in Wales who had a manufacturing concept that, if proven could deliver the relatively rapid and repeatable polishing process required. This is the project currently active in Glyndwr University’s St Asaph Campus at the Optic Centre.


The team at Glyndwr University have successfully developed a process that can directly polish the hexagonal segments over the full aperture whilst maintaining the edge form. This is an industry first! The team have also produced another world first with their optical test which is certified by ESO to deliver the 2nm RMS test accuracy required.


All of these ground breaking process developments have placed Glyndwr University in a very strong position to play a major role in the delivery of the large quantity of mirrors required for the telescope build. This work will go to tender in the third quarter of 2015 and we are currently working hard to ensure this fantastic manufacturing opportunity is won by the UK and manufacturing stays in Wales


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