A Telescopic Behemoth

by Nicholas Mee on June 25, 2014

The Starry Messenger

It is just 400 years since Galileo first pointed his telescope at the night sky – a mere five lifetimes ago. His enhanced view of the heavens brought about a revolution in our understanding of the universe.

Everywhere Galileo looked he made new discoveries. He found that the Moon was mountainous and cratered. He saw Venus as a crescent. He saw sunspots on the Sun and a myriad stars in the Milky Way. His most spectacular discovery was the existence of four moons dancing around that planet Jupiter. Galileo raced to get an account of his discoveries into print in a booklet called Siderius Nuncius (The Starry Messenger), which appeared early in the year 1610.  His sensational new view of the cosmos would overthrow the traditional understanding of the heavens and open the way for a transformation of astronomy.

In the centuries since Galileo every step onwards in our technology for viewing the heavens has generated dramatic discoveries. The improvements in equipment in recent decades has been incredible. We are currently living through a golden age of astronomical research.

Desert Astronomy

The European Southern Observatory (ESO) is funded by 14 European nations making it the most important inter-governmental body for astronomical research. The photograph below shows the site of ESO’s Very Large Telescope complex (VLT) which has been constructed at an altitude of 2,400 metres on a mountain top at Paranal in Chile. This site was chosen as it is within one of the driest regions on Earth – the Atacama desert. The incredibly low humidity and high altitude give the night sky an extra clarity, dramatically reducing the blurring effects of turbulence in the atmosphere above the observatory. The VLT is the most advanced optical observatory in the world. It consists of four main telescopes, each of which has an 8.2 metre diameter mirror, along with four 1.8 metre auxiliary telescopes.

The Very Large Telescope complex in the Chilean Andes (c) ESO.

The four main telescopes are named Antu, Kueyen, Melipal and Yepun. These are the names of four celestial objects in the local Mapuche language. Antu means Sun. Kueyen means Moon. Melipal means Southern Cross and Yepun means Venus. Antu was the first of these telescopes to come into operation in April 1999.

Adaptive Optics

Even in the almost ideal setting of an Andean mountain top there is still some atmospheric distortion of the starlight gathered by the huge telescope mirrors. To compensate for this distortion the VLT telescopes use adaptive optics. A laser is fired into the night sky. It reflects from the upper atmosphere to produce an artificial point of light or guide star. This guide star is then viewed through the telescope and a computer controlled feedback mechanism continuously deforms the mirrors of the telescope to keep its image sharp. The mirror deformation mechanism compensates for any fluctuations in the atmosphere and enables the telescopes to produce images that are much sharper than would otherwise be possible, rivaling a much more expensive space-based telescope.

In addition the four main telescopes and the four auxiliary telescopes can be operated as an interferometer in which the light from the telescopes is channeled through underground tunnels and combined to form an ultra-sharp image of incredibly high resolution.

The results are spectacular, as the image below demonstrates. This image shows a star-forming region in the dwarf galaxy companion of the Milky Way known as the Large Magellanic Cloud. The nebulae in the image have been produced by intense stellar winds from extremely hot new-born stars.

Star-forming region in the Large Magellanic Cloud (c) ESO.

The European Extremely Large Telescope

The European Southern Observatory has just started the construction of what will be by far the world’s largest telescope. The new behemoth will be known as the European Extremely Large Telescope (E-ELT). The site is on a mountain top twenty kilometres from the VLT complex, at an altitude of just over 3,000 metres. The composite mirror of the telescope will be constructed from 798 hexagonal segments, each 1.4 metres wide, making the full mirror a gargantuan 39 metres in diameter. This will enable the telescope to collect about 15 times as much light as any existing telescope. The telescope will incorporate an advanced adaptive optics system using several lasers and actuators that can distort the shape of the mirrors a thousand times each second.

The E-ELT will begin operation at the start of the next decade. Every advance in optical equipment has brought sensational discoveries about our place in the universe and the same will surely be true of the E-ELT. It will give astronomers the ability to search for the first generation of stars in the very early universe, it will enhance the search for Earth-like planets around distant stars and it will enable astronomers to probe the supermassive black hole at the centre of our galaxy, but it will also reveal the unexpected.

An artist’s impression of how the E-ELT will look when completed (c) ESO.

 Further Information

More information about the European Southern Observatory and its telescopes is available on ESO’s website at: European Southern Observatory

If you are interested in the history of astronomy from Galileo’s telescope to the supermassive black hole at the centre of our galaxy, take a look at my book Gravity: Cracking the Cosmic Code.

{ 7 comments… read them below or add one }

Liz Barnor June 27, 2014 at 2:21 pm

Thank you so much, Nicholas. I was always interested in astronomy before, but not to the extent I now do. I first developed an interest in the Cosmos with learning about theSolar system in primary school – it wasn’t that in-depth. You have taken me into the heavens with your monthly emails, showing me more than I ever hoped to see of the cosmos. Not only that, you’ve taken me closer to the planets and stars and explained in a simple language even I can understand, about the wonders of the skies. Best of all, you explain how these bodies are formed an0d work. My interest has sharpened and I eagerly anticipate receiving your feeds/news from the skies. What I wouldn’t give to actually travel up there to observe all the wonderful inter-stellar and inter-galactical bodies you’ve introduced me to. I’m getting your new book so I can learn more. Isn’t it beautiful in the galaxy?


Deodath Lalbeharry June 28, 2014 at 8:49 pm

Thank you Prof. for your recent article re building of a gigantic reflecting telescope which will be able to capture and bring to light the inner secretes of the universe, but in a decade’s time I’m not sure if I will be around, but I will keep the faith.

I have made a request with amazon.com for your recent book and was advised that I will be informed when copies become available.

Deodath Lalbeharry


l.pal June 29, 2014 at 12:44 pm

Thank you sir.

Astronomy is always my favourite subject.
The pictures you send make it more interesting.



Trudie Robat July 12, 2014 at 5:40 am

Wow! How far can technology go to conquer the heavens. It’s wonderful how far they have come already. Thank you Nicholas for this most interesting information.


Om Prakash August 8, 2014 at 6:18 am

Thanks a lot Mr Nicholas Mee for providing latest information in the field of Astronomy. I used to go through all the topics available on NET . Books published may be available in indian market or not may kindly be informed. Thanks again


Nicholas Mee August 21, 2014 at 7:20 am

Currently my books are not available in Indian bookshops, as far as I know. However, they are available online from Amazon and the following website: http://virtualimage.co.uk/html/higgs_force.html


Frank Soto September 14, 2014 at 6:50 pm

Your lucid succinct and entertaining description of the most complex subject matter do not cease to amaze this retired nuclear engineer.
Gratefully yours,
Francisco Soto


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