J. Brit. Astron. Assoc., 107, 2, 1997, pp.104-105
The annual Scottish Astronomy Weekend was held this year at the City Observatory, Calton Hill, Edinburgh and organised on behalf of the Scottish Astronomers' Group by Dr David Gavine. Our host on this occasion was the Astronomical Society of Edinburgh, represented by their President Mr Jim Nisbet and Secretary, Mr Graham Rule. Mr Jamie Shepherd, Director of the City Observatory, organised the internal facilities. Accommodation for participants travelling from afar was provided on Newington Campus.
On Friday evening, after speeches of welcome, Professor Andrew Lawrence of the University of Edinburgh gave a talk entitled 'Stars, Galaxies and the Search for Meaning'. The vast scale of the Universe was explored together with its energetic and violent nature. In contrast mankind was minuscule, but life forms were complex as compared to the relative simplicity of the physical Universe. Professor Lawrence considered the possibility of there being other centres of life, and methods whereby humans could communicate or be communicated with. The talk concluded with a review of the recent detection of planetary objects in orbit about nearby stars and how these could be observed.
Alan Pickup of the Royal Observatory, Edinburgh (ROE) opened the Saturday morning session with a talk entitled 'Great Comets'. He tried to define what made a great comet and examined the records of a number of well-known examples such as the circumpolar comet of 1811, Tebbett's comet of 1861 and many others. Dr Pickup concluded that great comets, easily seen, were those that were accompanied by dust tails. Comets with only ion tails were not well seen.
Brian Kelly of the Mills Observatory, Dundee, spoke on 'Space Debris', which was essentially a review of the history of meteor observing: the development of visual, photographic and spectroscopic studies. The origins of meteors and their types were described, some being stony and others being metallic. There appeared to be no known falls to earth of meteorites from comets which were dusty in nature. Asteroids could produce meteors but perhaps Phaeton, for example, was the solid core of an old comet.
After morning coffee Dr John Reid described 'The Physiology of Observing' as it affected the amateur astronomer. The working and defects of the eye, the ganglion system, the optic nerve and the brain's processing of optical information were examined. Dr Reid showed how these factors related to observing by day and by night. He considered the effects of cold on the body's core temperature and the cooling of body extremities which during long winter observing sessions can lead to loss of efficiency, skin complaints, non co-ordination and in extreme cases hypothermia and even death. Dr Reid concluded his talk with examples of the different kinds of spinal injury that can be brought on by positional contortions and uncomfortable postures at the telescope – while kneeling at the eyepiece could bring about housemaid's knee.
After lunch participants were free to choose their own activity. Alan Pickup arranged a visit to the ROE. Dr David Gavine took a party to look at the geology of Arthur's Seat. It was Doors Open Day in Edinburgh and visitors were able to inspect the interiors of some of the many buildings available to view.
In the evening, despite a horrendous cold, Dr John Mason delivered the Merson Lecture entitled 'The Leonid Storm'. Dr Mason described the history of observing the Leonids and how a 33-year periodic increase in meteoric activity came to be noted, how the radiant was determined, and the work involved in calculating the orbit of the meteors about the Sun together with its perturbations. The contributions of von Humboldt, Bonpland, Olbers, Newton, John Couch Adams, Herschel of Glasgow and others towards the understanding of the Leonid phenomenon were explained. The relation to Comet Temple–Tuttle was described. It was demonstrated that the presence or absence of a periodic Leonid meteor storm was related to whether the perturbations of the orbit brought it inside or outside the Earth's orbit, and reference was made to studies by Don Yeomans, Nick James and Dr Mason himself. As a consequence of these studies Dr Mason predicted that a Leonid meteor storm would take place in 1999, a prediction more reliable than that for the English weather in the forthcoming Cornish solar eclipse. After such an outstanding performance under such trying circumstances Dr Mason was given prolonged applause by the assembled company.
On Sunday morning, the Members' Session was opened by Tony Hopwood who showed NLC photographs in a series that indicated an apparent cloud movement of 18 km/minute. He then described his instruments and recording system for measuring the arrival of cosmic particles, neutrons from the Sun, atmospheric electrical field potential, solar ultraviolet radiation, radio high frequency propagation levels and Earth currents. He showed correlation between different parameters caused by solar activity. Particle counts fell as solar activity rose. It was possible to detect solar UV even in cloudy conditions. Earth current measurements were a very simple method of measuring geomagnetic activity caused by current activity in the ionosphere. His equipment was particularly useful for detecting solar flares.
Dr John Reid exhibited slides of Comet Hyakutake taken in North Scotland and abroad, the weather in the UK at the time being very poor. He found Fuji 800 SJ film to be the most suitable for astrophotography.
Professor John Brown, Astronomer Royal for Scotland, gave an amusing account of some of the things he had become involved in since taking office. He was encouraging astronomy for the school curriculum. There were now three portable planetaria in Scotland suitable for demonstrating astronomy to schoolchildren. His observation of Comet Hyakutake from the car park of the Edinburgh Hilton Hotel was light-hearted. He confirmed that the ROE was a centre of technical excellence known to those who mattered, in spite of government moves to do away with it. Professor Brown described how he and the Lord Lyon came to design the coat of arms for the office of Astronomer Royal for Scotland in which the constellation of Orion, James Short's telescopes and the Saltire of Scotland feature. He was glad to attend this Weekend as a refuge from his desk, letter writing and administration generally.
Nick Martin of the Ayrshire Astronomical Society showed slides of Comet Hyakutake. The audience had been issued with polaroid spectacles normally used on Calton Hill for a three dimensional slide show of the history of Edinburgh given to the public. Mr Martin showed a stereo pair of photographs taken three hours apart, and with the shift of the comet's position relative to the background of the stars, this resulted in the comet standing out in front of the stellar background in three dimensions. Mr Martin said he had seen flickering bands of light in the comet but did not know if this was real or an artefact of the Earth's atmosphere. Discontinuity in the tail had also been observed. Dr Alastair Simmons commented that changes in ion tail brightness bore a strong resemblance to solar ultraviolet light stimulation of sunlit aurorae.
After the coffee break Jamie Shepherd reviewed his long experience with fish-eye lens photography and also with a home-made camera. Light pollution in central Scotland made him use an observing site near Lochearnhead where sky conditions were much better, which he demonstrated with colour slides. Mr Shepherd also showed examples of meteor photography and how two-station stereoscopic photography could be used to assist in orbital studies and help to find where a meteorite might have landed. Star photographs in good skies were too busy, and a technique was used to mask down the exposures to produce pictures in keeping with the sky as seen with the naked eye. Mr Shepherd hoped one day to produce a photographic star atlas.
Robert McNaught on leave from Australia gave a talk on near space objects with a potential for Earth impact, comprising asteroids, comets and meteors. Amor objects have orbits outside that of the Earth; Apollo objects are Earth-crossing and Aten objects stay wholly within the Earth's orbit. Perturbation of the orbit could send any such object into a potential impact orientation. It is estimated that two objects per day with a diameter greater than 10 metres pass through the Earth–Moon system. Any object greater than 0.5 kilometres in size would radically affect civilisation if it impacted the Earth. The probabilities of impact for various sizes of object were considered and the probability of death from a potential impact compared with other actuarial risks. The retardation effect of the break-up of an object in the Earth's atmosphere before impact was illustrated.
On conclusion of the Sunday morning session Dr Alastair Simmonds, President of the Scottish Astronomers' Group proposed a vote of thanks to all speakers, the Weekend organisers and all participants for their joint efforts in making the event such a success. He also thanked Rosemary Naylor for providing her bookstall and Peter Hudson for bringing a BAA sales stand.
R. J. Livesey
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