Papworth Astronomy Club

This month’s meeting was an interesting history of the nineteenth century observer Charles Piazzi Smyth. This talk was given by Dave Eagle, a Fellow of the Royal Astronomical Society and an old friend of the Papworth Club.

Charles Piazzi Smyth (1819-1900), was the son of the renowned English amateur astronomer, Admiral William Henry Smyth. Charles got his middle name from a family friend Giuseppe Piazzi, the famous Italian astronomer who discovered the first asteroid Ceres in 1801.

Smyth was Astronomer Royal of Scotland and in 1856, he undertook his famous scientific voyage to the mountain peaks of Tenerife – on his honeymoon! Here he pioneered the modern practice of siting telescopes at high altitudes for better observing conditions. He also made an estimate of the amount of heat radiation received from the Moon, and thus pioneered infra-red astronomy. Dave illustrated his talk with pictures from his own visit to Tenerife where he visited the ruins of Smyth’s observatories on the mountains (pictured above).

Unfortunately Smyth had a major obsession with the pseudo-science of pyramidology, which is founded in the belief that the measurements of the Great Pyramid contain a mystical significance. Indeed he was the only person ever to have resigned his fellowship of the Royal Society, following their refusal to publish his pyramid papers. He apparently offered his resignation in the hope that it would be refused, but the members called his bluff and he lost his fellowship!

Dave concluded the talk by showing some of his own astronomical images that he had taken on the mountains after dark. The show was accompanied by some Pink Floyd, which is appropriate for a Cambridgeshire venue. He promised to give us more on his imaging at a later date, so keep an eye out for future programmes.

Planetary science came to Papworth in the form of a talk by Open University researcher Susan Conway. She has been studying the mysterious gullies that were revealed in high resolution images by the Mars Global Surveyor spacecraft.

These surface features support the idea that water has been present on Mars, but exactly how these features have formed in the distant past of the red planet is unknown. To try and find out, she has looked closer to home at similar geological features on Earth, in Iceland, England and elsewhere. Using modelling techniques, she showed that at least some of the Martian gullies were probably formed by movement of sediment down slopes in a similar way to that found in Iceland. She has successfully reproduced these phenomena in a sophisticated sandpit enclosed in a vacuum chamber and chilled with liquid nitrogen. This is apparently the first time this has been tried in the laboratory and is helping to answer the question of whether surface water (in the form of ice) was present when the Martian gullies were formed. Water of course means the possibility of life, but that’s another story. The Club is grateful to Susan for her fascinating talk.

Cosmology has always been of interest to Club members and therefore the talk by Carolin Crawford on “A Beginners Guide to Cosmology and Dark Energy” was much enjoyed and appreciated. As well as being a staff scientist at the Institute of Astronomy, Carolin is also a public outreach officer, and her talk reflected the care she takes to make complex information understandable by a lay audience.

The talk started with an introduction to the discoveries in the mid 20th century that led to our current understanding of the universe. Einstein’s General Theory of Relativity produced different scenarios for the fate of the universe depending on a mathematical device, the Cosmological Constant. Subsequent observational work by Edwin Hubble showed that in fact the universe is expanding. Given that it started out at the Big Bang, the universe was estimated to be over 14 billion years old.

More recent observations of supernovae and galaxy clusters were described, which imply that the rate of expansion is actually increasing, giving a revised figure of 13.7 billion years for the age of the universe. The force driving this expansion is known as Dark Energy, but the nature of this energy is one of the great mysteries of modern cosmology. Carolin’s talk prompted a range of questions, some of which inevitably verged on the philosophical given the nature of the subject. The evening gave us plenty to think about as we looked up at the Papworth night sky on the way home!

The history of astronomy is a popular topic for Papworth meetings, so we were pleased to have Mark Hurn give us a talk on Sir Robert Stawell Ball for our May meeting before the summer break. (That’s Sir Robert in the picture above – not Mark!)

Sir Robert was a nineteenth century Irish astronomer who became Astronomer Royal for Ireland and later worked at the University of Cambridge where he had special accommodation built for his extensive family. His observational astronomy days ended prematurely after removal of one of his eyes, but he made significant contributions to mathematics and particularly to the popularization of astronomy through his many books.

Mark Hurn is librarian at the Institute of Astronomy so has access to  a number of old books written by Ball which he brought along to the meeting to show us.  Mark made the point that it is fascinating to read about past astronomical theories in the light of our present knowledge. Ball, for example, believed that meteorites came from earth, not from the solar system and argued his corner vigorously. We now know of course that many of these objects come from Mars, but one can imagine how this might have been difficult to envisage over 100 years ago. Sir Robert Ball died in 1913 and is buried in Cambridge in the Ascension Parish Burial Ground, near Storey’s Way.

The club was treated to a tour de force of a talk from Gary Poyner, who came over from Birmingham to tell us about of variable stars in all their different forms. Gary has been observing these objects for forty years and is an acknowledged expert in the field, having been head of the variable star section of the BAA. He started the talk with a striking image of the summer constellations overlaid with an enormous numbers of variable stars that are visible by eye or through binoculars. This came as a surprise to those of us who thought that there were only a few such objects, like the famous Algol and Mira. Gary then went into detail about the different astrophysical mechanisms that give rise to variability in the brightness of stars; these included simple dimming of light by eclipsing binary stars to dramatic shifts of stellar material to form accretion discs. Throughout the talk he used animations to illustrate each mechanism and this certainly helped the non-expert. From the perspective of the amateur observer, it is interesting to see how accurate light curves of the many different types of variable stars can be produced just by using binoculars, a small telescope, or even the naked eye. The key is to use star charts with reference stars of defined magnitudes. Apparently it is possible to achieve an accuracy of 1/10 magnitude by eye and of course much greater with CCD images. Gary’s talk certainly gave us food for thought about the contributions that amateurs can make to astronomy through work on objects like variable stars. The following websites give more details:

• http://www.britastro.org/vss
• http://www.aavso.org

Winter may be making an unwelcome comeback in early March, but this wasn’t a problem for club members at their observing session next to the Vinter Room.

A number of portable telescopes were set up in an area that is relatively free of light pollution from the street-lamps of Papworth, and Lee Sproats from Green-Witch in Dry Drayton brought along a 6-inch Celestron Nextar for us to try out.

The cold evening meant clear skies, with a number of interesting celestial objects on view. The Nextar gave superb views of the moon and Comet Lulin, and even the M86 galaxy was visible despite the moonlit sky. Thanks Lee!

This was a highly successful meeting that encouraged friendly exchanges of information and observing experiences between club members.

January 7th

Members’ Evening

February 4th

Anna Quider

“Humans in Space”

March 4th

Lee Sproats, Green Witch – Observing session

April 1st

Gary Poyner – “Variable Stars”

May 6th

Mark Hurn – “Sir Robert Stawell Ball”

August 5th

Thirteenth annual summer picnic

September 2nd

Carolin Crawford – “Cosmology and Dark Energy”

October 7th

Susan Conway – “Martian Gulleys”

November 4th

Dave Eagle – “Charles Piazzi Smyth”

December 2nd

Lee Sproats, Green Witch – Observing session