Royal Observatory at Greenwich working for first time since London smog shut down telescopes 60 years ago

Brendan Owens with the AMAT telescope at the Royal Observatory at Greenwich - Anthony Upton
Brendan Owens with the AMAT telescope at the Royal Observatory at Greenwich - Anthony Upton

The Royal Observatory at Greenwich has been pivotal to astronomy and navigation since the beginning of time. Well, international standard time at least. But what few people realise is that the observatory has not actually observed anything for more than half a century.

Astronomers were forced to abandon their work in the 1950s as London smogs grew so bad that they could no longer see the stars through their telescopes.

As the railways expanded nearby, the rumble of trains also made it impossible to take accurate readings with sensitive instruments, while the ever-growing capital brought increasingly dazzling light pollution.

Now, after more than 60 years a new telescope has been installed at Greenwich to restore its status as a working observatory once again. Not only is London’s air cleaner now, but modern telescope filters can tune out the pollution to hone in on the stars, planets, nebulae and even galaxies.

Curator of Royal Observatory Greenwich, Dr Louise Devoy said: “The observatory really started to wind down in 1948 because Greenwich had been expanding, and Greenwich Power Station was belching out smoke so the telescopes were becoming useless.

“They also used to do magnetic and meteorological readings from here, but the railways and iron-framed buildings interfered with the signals and the vibrations from the trains made accuracy impossible. With the new telescope we can use filters and software to process it all out.”

 AMAT's dedicated Hydrogen-Alpha telescope captures dynamic activity in the Sun's broiling atmosphere  - Credit: Royal Observatory Greenwich AMAT
AMAT's dedicated Hydrogen-Alpha telescope was capable of capturing this incredible image of activity on the Sun Credit: Royal Observatory Greenwich AMAT

The Royal Observatory was founded in Greenwich in 1675 by Charles II for the purpose of improving navigation at sea through astronomical means by mapping the fixed location of the stars.

It was a working observatory until 1957, when the site and its instruments were moved to Herstmonceaux in Sussex while the Greenwich site was preserved as a museum and outreach centre to encourage public interest in astronomy.

But last year the Royal Museums Greenwich launched a campaign to restore the observatory to working status, raising more than £150,000 to buy the telescope and revamp the Grade 2 listed Altazimuth Pavilion where it is housed, a nautically inspired Victorian masterpiece designed by naval engineer William Crisp.

The Annie Maunder Astrographic Telescope (AMAT) named after one of the first female scientists ever to work at the observatory, is actually four different telescopes, the largest of which will allow astronomers to produce high magnification views of The Moon and planets in the Solar System.

The AMAT also has a solar telescope to catalogue changes to the Sun, a practice started by Greenwich astronomers in 1870, and something Annie Maunder herself was doing in the 1900s.

Rugged terrain on the waxing gibbous Moon as captured through AMAT's 0.35-metre telescope - Credit: Royal Observatory Greenwich AMAT
Rugged terrain on the waxing gibbous Moon as captured through AMAT's 0.35-metre telescope Credit: Royal Observatory Greenwich AMAT

Astronomer Brendan Owens said: “Urban astronomy has come a long way, and we have to thank amateur astronomers for a lot of the developments that have allowed us to do this.

“We now have filters which completely block out the wavelengths of light from things like street lamps and instead just focus on the hydrogen, oxygen and sulphur dioxide that are coming from stars and planets.

“As well as highly magnified images of the Sun and Moon, we have a cooled digital camera to take very wide views of the sky so we can see nebulae and galaxies.”

The astronomers are hoping to use the observatory to witness the lunar eclipse on July 27th when the moon will turn a deep dark red colour close to the horizon - known as blood moon -  as it passes completely into the Earth’s shadow.

“It should be quite spectacular,” added Mr Owens, “Because it will be close to the horizon so it should look huge and be a reddish colour. We can also use the red tinge to tell us about pollution in the air, as that changes the colour of the moon during an eclipse.”

AMAT  - Credit: Anthony Upton for The Telegraph 
The AMAT telescope in Greenwich Credit: Anthony Upton for The Telegraph

They are also hoping to view next year’s transit of Mercury when the planet will cross in front of the Sun.

Annie Maunder,  first joined the observatory in 1891, processing data as a ‘lady computer’, one of the few paid opportunities for women in astronomy at the time.

She was forced to give up the position when she married in 1895, but continued her scientific endeavours alongside her husband, embarking upon solar eclipse expeditions across the world.

Their joint work in mapping sunspots established a link between solar activity and the Earth’s climate, which lay the groundwork for modern understanding of the Sun and its cycles.

Tours of the facility and Altazimuth Pavilion will be available to book throughout the year. Visitors will also get the chance to see the images produced by the telescope via an interactive screen which will feature in an exhibition space, due to open on the lower ground of the Altazimuth Pavilion later this summer, which will also tell the story of Annie Maunder.

Hazy days: How Great Smog made London stand still

On Friday Dec 5 1952, a thick yellow smog brought London to a grinding halt. The worst effects lingered for nearly five days and killed as many as 10,000 people.

Helped by an unusually cold and windless weather front from Europe, the smog stopped traffic and trains; and closed theatres as audiences couldn't see the stage.

 Two passengers looking at the train departure board at Liverpool Street Station, London, during heavy fog, 29th January 1959 - Credit: Edward Miller/Hulton Archive
Heavy smog at Liverpool Street Station in London in the 1950s, when astronomers were forced to abandon their work as they could no longer see stars through their telescopes Credit: Edward Miller/Hulton Archive

The government said that 4,000 people died, but undertakers ran out of coffins, and historians now say the death toll was far greater.

The situation was made worse by the fact that at the time London was the world's biggest city and nearly all 8 million of its inhabitants used open coal fires.