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June 18, 2012

Jubilee Party: Members’ Talks

Mike Dryland, Dave Redfern and Ian McDowell
Report by: Chris Sutcliffe

The last meeting of the season

With Greenwich moving into Olympic mode, but at the same time, many exciting things taking place such as the Royal River exhibition in the National Maritime Museum, this was a special meeting with three talks given by Flamsteed members as follows:-

 

The Great Melbourne Telescope by Mike Dryland

Mike Dryland

Melbourne has had a small observatory since the 1860s when it was set up by the Government of Victoria. However, when you go to the observatory today, there is not a lot to see (unless you catch the Astronomical Society of Victoria at a stargazing evening), but this has not always been the case.

In the early 19th century one of the Big Questions in astronomy concerned the nature of the ‘nebulae’ – tiny fuzzy cloud-like patches in the night sky.  Were they clouds of gas, or very distant collections of stars, too distant for individual stars to be seen, and were they areas of star formation, or remote galaxies, or what?  Early work on nebulae was done by Halley and Messier, but almost all the substantial research was by talented (and rich) amateur astronomers, most notably William Herschel (1738 – 1822).  Herschel became the world’s best telescope maker, and with his 7-ft (length of tube) 6-inch reflector, he discovered Uranus in 1781.   His son, John Herschel travelled to the Cape of Good Hope and did a study of nebulae in the southern hemisphere.  John was particularly interested in the Carina nebula located in the sky between the Southern Cross and Canopus.

Subsequently, William Parsons (3rd Earl of Rosse) produced the world’s largest telescope, a 72-inch reflector which he used to study nebulae from Birr Castle in Ireland.  Rosse successfully resolved M51 (the Whirlpool Galaxy) and a few other nebulae into stars, thereby discovering ‘spiral’ galaxies.  Some astronomers began to argue that all nebulae were distant collections of stars.  A friend of Rosse’s, Thomas Romney Robinson (Director of the Armagh Observatory for 59 years) became involved and thought it would be good if a telescope similar to Rosse’s could be set up in the southern hemisphere to study the southern nebulae.  At Robinson’s prompting, the Royal Society set up a Southern Telescope Committee in 1852 to develop proposals.  The committee consisted of Rosse, Robinson, John Herschel, Airy, Lassell, Nasmyth, and several other worthies.  The Committee endorsed a design by Thomas Grubb of Dublin for a 48-inch telescope (he had previously built a 15-inch Cassegrain reflector for Robinson at Armagh).

The southern telescope committee considered the following:-

  • a reflector or a refractor? (They chose a reflector)
  • how big? (They chose 48-inch)
  • an equatorial or altazimuth mounting? (They decided upon an equatorial mounting)
  • a Cassegrain or Newtonian reflector? (They chose a Cassegrain)
  • a metal or a glass mirror? (They chose a ‘speculum’ metal mirror – silvered glass mirrors had just been invented but were experimental and nobody had built a large glass mirror)
  • where this should be situated? (They decided upon the Cape of Good Hope)

In 1853 they recommended to the British Government that such a telescope should be government-funded.  Unfortunately their timing was rotten — the Crimean War had broken out — and the proposal lapsed for almost 10 years.

Back in Australia, in 1851 the State of Victoria had been created with Melbourne as its capital. In the same year gold was struck, and Victoria was flooded with people and money.  At the new University of Melbourne, William Parkinson Wilson became founding Professor of Mathematics in 1854.  He knew George Airy (Astronomer Royal, and Director of the Royal Observatory in Greenwich), Herschel, and Robinson, and was aware that the southern telescope project had been shelved.  Wilson proposed that the State of Victoria should fund the telescope to be sited in Melbourne.

After much campaigning, in 1865 the Government of Victoria provide the sum of £5,000 for the southern telescope to come to Melbourne. It was to be a Cassegrain reflector, and Grubb of Dublin was given the contract.  Thomas Grubb’s son Howard dropped out of Trinity College Dublin to lead the project.

In November 1868, the Great Melbourne Telescope arrived in Australia.  The first observer, Albert Le Sueur, supervised the set-up and with great expectations, began work.   Unfortunately Albert soon ran into trouble complaining that the telescope was not performing well.  There followed an exchange of letters between Melbourne and Britain in which some advice was offered but there was no move to send help.  Expert opinion tended to put the blame at Albert’s door – he had little experience and the Melbourne observatory had few resources to help him.  In 1870 he quit and returned to England.   The main problem seems to have been that the metal speculum mirrors tarnished quickly, and re-polishing was a tricky task especially for the local staff who had little experience.  A new observer, Joseph Turner, an experienced photographer, was hired in 1873. With the telescope, he obtained good photographs of the moon in 1874, and pioneering photos of the Orion nebula in 1883.   Polishing of the mirrors continued to be a challenge.  Eventually the Government Astronomer, Robert Ellery, learned how to grind the mirrors but he was too late.

In 1885, a fourth observer, Pietro Baracchi, published a catalogue of drawings of nebulae made using the telescope, but by 1888, the telescope was being little used, and progressively declined.  Other priorities had come along and the observatory never really had the resources or expertise needed.   The experts back in Britain had lost interest and the telescope had been written-off as a failure.  It was to be the last big telescope made with a metal mirror.  Soon after it was made, large glass silvered mirrors were perfected and all modern reflecting telescopes are now made this way.

In 1944, the State of Victoria closed the observatory and it looked like the end for the Great Melbourne Telescope which was put up for sale.  Reprieve came when Richard Woolley, then Director of the Australian Commonwealth Observatory, purchased the telescope and in 1957 it was erected at Mt Stromlo Observatory near Canberra.  The scope was re-built with a modern glass ‘Pyrex’ mirror and gave good service doing photometric surveys until 1973 when a bearing failed and it had to be retired.  Yet another lease of life started in 1992 when it was rebuilt as a fully automated instrument and used searching for MACHOs via gravitational micro lensing events.

The MACHO project ran successfully until late-1999 when the telescope was retired once more and planning began for yet another incarnation, but… on 18 January 2003, the observatory was wrecked in a bush fire.  Much of the Mt Stromlo site was destroyed including the Great Melbourne Telescope.  Farewell then, Great Melbourne Telescope.

Not quite.  Starting in 2008 a joint project between Museum Victoria, the Royal Botanic Gardens Melbourne, and the Astronomical Society of Victoria, set out to rescue the telescope.  Some of the original parts, including one of the metal mirrors, had been kept after the rebuilds, and the remains at Mt Stromlo were lovingly dismantled and sent to Melbourne. There is no shortage of volunteer energy but at least a million dollars will be needed to restore it.

At this point, Mike concluded this fascinating account of the history of the Great Melbourne Telescope with the hope that this will be continued at a later date.

Read more at –

Great Melbourne Telescope project

Melbourne Observatory

Museum Victoria G.M.T.

Royal Society images

‘The Age’ newspaper, February 2012

Wikipedia on the G.M.T.

Mt Stromlo G.M.T. page

Sydney Observatory G.M.T. visit

 

Science and Belief by Dave Redfern

David is an artist, and with his creative talent and depth of thought, has been producing unusual works of art at this studio in Deptford for over 30 years.

If you see a person delving into skips in the London Borough of Lewisham, it is likely to be David looking for materials for his artwork e.g. paint pots, wooden frames, old cabinets etc.

David showed some of his fascinating creations illustrating the link between religion and belief, and science; between the exploitation of natural resources and new technology.

Of particular interest, David obtained an aerial view of Frombork cathedral where Nicolaus Copernicus worked. Copernicus spoke to his congregation and sat in the tower of his cathedral using an astrolabe. David produced an artwork showing the planetary alignment on the day Copernicus died – amazing!

David showed works based upon Raphael’s famous fresco in the Vatican and the 200” mirror from the Mount Palomar telescope which was transported from New York in a bullet proof container.

With David’s preview of his some of his creative works of art, a visit to his Deptford studio could be a rewarding experience.

 

Mars Science Laboratory by Ian McDowell

On 6 August 2012, the Mars Science Laboratory (MSL) is scheduled to land on Mars.

Its Rover landed last November in Gale Crater which is 150 km across and 4.5 – 5.5 km in height; this particular crater has been the subject of previous pre-assessment rovers.

MSL is powered by a thermonuclear system and its goals are as follows:-

  • explore the geology of Mars
  • discover whether life ever existed on Mars
  • study the climate on Mars
  • prepare for human exploration

The landscape of Mars is generally lower in the top half, and higher in the bottom half, but the top area of Mars could be craters in-filled with lava flows.

MSL’s landing system is complex with 15 camera systems and MARDI, the Mars Descent Imager.

Ian clearly conveyed the potential which this mission has for making some exciting discoveries.

As time was short, members had the opportunity of asking questions of the three  speakers over drinks which followed.

Sparkling wine was served to round off a sparkling evening, and Lin proposed a toast to Flamsteed, all the good things which are taking place in Greenwich during the summer, and the Olympics.

 

Pictures from the evening (by Grey Lipley):

Posted under: Flamsteed, Flamsteed Lecture, Meeting Report