As is traditional, the OAS Christmas meeting had no formal speaker. However, we did have a healthy quantity of Christmas food ranging from nibbles to Gateaux.

We were however treated to Jim's scintillating Chairman's Address and a quiz as set by Miriam and Jeff. As it came from one of our smarter members, the questions were of a tricky astronomical nature, and at times, fixated on minor planets.  It was a close run contest, with some teams actually answering some of the questions but victorious was a team called Allouette.

The Christmas meeting wrapped up (pardon the pun) after more consumption of goodies and closed another fantastic year of OAS meetings, speakers and events.

The evening started with a short report by Jim Mehta of our recent visit to Mill Hill Observatory. After coffee, Prof. Ian Morison gave us a fascinating talk on "The Story of Jodrell Bank". The first instrument at Jodrell Bank was an ex-army radar set up by Bernard Lovell in a corner of the Manchester University Botanical Grounds in late 1945. Lovell used this instrument to prove that sporadic echos observed on radar instruments were caused by reflections from the ionised trails of meteors. From this humble beginning, Jodrell Bank went on to become one of the major radio astronomy establishments in the world. A position the observatory maintains today with it's envolvement in Merlin. With an effective aperture of 217 kilometres Merlin has a resolution greater than 20 times that of the best ground based optical telescopes. That's equivalent to measuring the diameter of a pound coin on the cliffs in Dover from the top of Shooters Hill

This evening's main talk on "Galileo and his Telescopes" was given by Steve Ringwood. He began by setting the historical context. Italy consisted of a number of City States, James I was dealing with the after efects of the Gunpowder Plot, Luther and the Reformation were stirring the Church, and Shakespeare was publishing his Sonnets. Galileo, who was teaching physics in Padua, got news of a device being used in the Netherlands, and, having heard a very brief description of its constituent parts, was able to construct a small working telescope. He quickly improved the design, and was able to sell a number of them. It was several months before he thought to turn his telescope on the heavens, but once he did he made a number of interesting observations, and soon published a book of them. Much of Galileo's story is tied up with the Church and the conflict between the Copernican and Ptolemaic descriptions of the known universe. His telescopic observations supported Copernicus' explanation, and the Inquisition eventually managed to bring him to trial. It's likely they doctored the evidence in order to convict him and force him to recant his support for Copernicus, but even when he was under house arrest Galileo continued to make observations, and to continue work on materials and motion. A book he published at this time was one which later influenced Newton. Galileo did not invent the telescope, but he was able to make better ones than many of his contemporaries, and his astronomical observations did much to lay the foundations for modern physics and astronomy.

Mark Shelley followed on from his talk about using digital SLRs for astrophotography (at the June Members' Evening) by explaining the various image processing steps which need to be performed to turn raw astro-photographs into finished images. Critical to the process are the Bias, Dark and Flat frames which allow the imperfections in the Light frames to be corrected, and Mark's slides clearly illustrated the effects of each.

After coffee, Ken Pearson gave us a talk about the Loughton Astronomical Society's observatory and telescope. He was heavily involved in re-building the telescope and refurbishing the observatory in the late '90s, and adapted a security camera for use with the scope for public observing sessions. He showed us a number of videos taken with the equipment at the time. Sadly, the observatory is no longer in use, as a tall block of flats has been built close to it, but the scope's optics are now part of a Dobsonian. Ken wrapped up his talk by showing a few slides of holiday locations with facilities for practical astronomy.

This evening's main talk on "Impact Cratering" was given by Dr. Emily Baldwin. She showed us examples of impact craters of various sizes from the microscopic to craters covering a third of a planet. Craters of different sizes show specific features, with the smaller ones having a simple bowl-shaped form, larger ones having a central peak, and the largest having multiple rings and often central lava-levelled plains. She then explained some of the dynamics involved, and the features they produce, and showed us some of the results of practical experiments, some of which involved investigating the effects of water on impact events. She rounded off the talk by telling us a bit about various space missions like Deep Impact and SMART 1 which have caused observed impacts, and showed us film of a prototype "lander", four of which, it is hoped, will bury themselves in the Lunar regolith by landing a little less than gently. In passing she also mentioned the possibility of rocks from the early Earth having found their way to the Moon as a result of the early period of heavy bombardment the Earth is known to have suffered. If any such rocks could be found on the Moon and returned to Earth, they might reveal details about the Earth's early history.

This evening's main talk, "The History of the Calendar", was given by Keith Brackenborough. The main purpose of a calendar is to keep track of the days, and make the business of planning, and recording the passage of the years easier. Of course the Earth and Moon do not make this an easy task. The Earth's most obvious unit of time is the solar day, but it also orbits the Sun in one tropical year, which is, of course, not a whole number of days long. The Moon orbits the Earth, and of course its period is neither a whole number of days nor a whole fraction of a tropical year. Throughout recorded history people have used calendars which took account of the various differences more or less successfully. Keith's talk covered many of the schemes that have been tried, from the relatively simple Lunar ones to schemes involving cycles many years long. He gave particular emphasis to the development of the calendar used by most of the world today, from its roots in Julius Caesar's ideas for bringing order to Rome's chaotic calendar, through Augustus' tinkering with the lengths of the months, the Council of Nicea's adjustments for determining the date of Easter, and Pope Gregory's reforms to account for the slight inaccuracies in Julius Caesar's original scheme. He told us about the way the Gregorian calendar was adopted slowly over the centuries by more countries, so that it is now the most common calendar, and should be adequate for at least another 2000 years.

After the usual run of society notices, Mike McRoberts gave us his observing notes and astrophotography challenges for July. Tony Buick gave us a talk about Tardigrades and the TARDIS experiment, which was launched on the Russian FOTON-M3 mission in September 2007. Tardigrades are very small animals which can take on an extremely hardy form to survive prolonged periods in hostile environments, and then "come back to life" once conditions become more amicable again. The TARDIS mission exposed some unfortunate tardigrades to the vacuum and radiation of Low Earth Orbit, and then returned them to Sweden. We're waiting to hear whether they survived the experience. Tony brought along a microscope and some live tardigrades for members to see.

After coffee Mark Shelley gave us a talk about using digital SLRs for astrophotography. This included tips on how to get images into sharp focus, and on "modding" a digital SLR to remove the manufacturer's IR and UV filter in order to improve its H-alpha response. He illustrated the effects with a number of astrophotographs, some of which can be found in the Society's gallery.

Mike McRoberts then brought the evening to a close with a talk about the Phoenix Lander, which has (at the time of the meeting) been on the surface of Mars for 31 Martian days. Reports from this mission will be well worth watching out for in the next few months.

Conrad Malin-Smith gave us a talk on The Message of Starlight. In it he explained just how much it was possible to determine by examining the spectra of stars and nebulae. The relative brightnesses of emission and absorbtion lines reveal a great deal, not only about composition, but also about temperatures, masses, and relative motions of the objects being observed.

The Society's first meeting at the new High Elms Nature Centre was the occasion of Lucie Green's talk about the "Latest Results from the Hinode and STEREO Space Missions". She began by explaining the structure of the Sun and went on to describe the various phenomena that could be observed on it. Having described sunspots, filaments, prominences, flares, and coronal mass ejections, she then showed us images from Hinode and STEREO. The Hinode mission carries three main cameras to give a wide spectral view of the Sun from the visible all the way to X-rays. It produces a much more complete image of the Sun's observable regions with excellent detail of the magnetic fields. The STEREO mission is a pair of spacecraft which have been observing the Sun from different directions. This has produced some fine views which we were able to view using stereo glasses to get a most unusual impression of the Sun's activity. Some of the images and videos may be found on the STEREO website .

The Society Annual General Meeting was held at Red Hill School, Chislehurst. At the meeting it was announced that we would be returning to High Elms Nature Centre for our March meeting, so this would be our last meeting at Red Hill School.

After the AGM had been concluded, our Chairman Jim Mehta gave us a talk about his recent visit to Siding Spring, the home of the Anglo-Australian Telescope. He was given a special guided tour of the observatory site by Fred Watson.

On this clear evening just after full moon Tom Boles gave us an interesting talk on "Discovering Supernovae". He began by explaining the differences between Type 1a supernovae (which happen when a white dwarf star which is accumulating material from a companion star grows beyond its maximum mass) and all the other types (which happen when massive stars run out of readily fusable fuel and suffer a core collapse). He then, after a short diversion explaining how supernova discoveries don't happen, went on to explain the procedures involved in finding potential supernovae, testing them to determine whether they are genuinely new, and then reporting them if they pass the tests. Finding candidates is largely a matter of imaging a sufficient number of distant galaxies and then comparing the images with reference master images looking for differences. Collecting images is a process that can be made very much easier by using robotic telescopes with good computer control. The trickier part is searching for significant differences, and them making sure that the differences can't be explained by anything other than a new supernova. Tom described the many ways differences might appear on images of  galaxy, from CCD errors and cosmic rays via variable stars and emission nebulae, to asteroids and artificial satellites. He then briefly mentioned some of the telescopes that have been used to confirm discoveries he has made. The list included the Keck telescopes, the Hubble Spase Telescope, and the Hale 200-inch telescope on Mt. Palomar. He ended his talk by describing some of the up-coming professional competition, and pointed out that though these will probably find a great many supernovae, they'll tend to find them in the fainter and more distant galaxies, so there'll still be a place for amateur supernova patrols for many years to come.