As 2012 draws to a close, we can reflect on yet another year during which the Society has flourished.
Membership numbers are still around 130 and we are at last attracting some younger members particularly as assistants at the Observatory. On the subject of the Observatory: when was the last time you visited it? If you haven't been there recently go and have a look, you will be surprised by the changes we have made during the Autumn.
For the last few years the dome covering has been steadily deteriorating, as it was last re-covered 35 years ago! We decided that it was time for action and we began work in September to strip off the old roofing felt and replace it. As often happens with major building work, once the process began we discovered a whole lot of problems with the structure of the building in general. Much of the wood work was found to be in a poor condition and it was clear that simply re-covering the dome was not enough.
Accordingly we decided to engage the services of a skilled carpenter and builder, Peter Gould, to assist with the renovations. The current Astronomy section Secretariat, although willing, now lack the physical strength to tackle some of the heavy lifting work required. To reinforce this point, Doug Daniels was laid low with a recurring back problem and sciatica which prevented him from assisting in any meaningful way; he did manage to make the tea on one occasion.
Apart from the main dome, the annexe roof and tunnel have been re-covered and the annexe has been re-panelled inside. Rotten floorboards and window sills have been replaced, the building framework has been strengthened and the whole building has been re-wired and safety cut-out devices installed. Additionally we have fitted a low level red light illumination system in the rotunda that looks very pretty at night.
The work took over three months and was directed by Simon Lang with the assistance of many members who generously gave up their time to help and for which we heartily thank them. As is to be expected, a major renovation such as this has been costly, to date it has cost £7500 and this has severely depleted our contingency fund. Simon, Peter and all those members who assisted, have done a first rate job and the Observatory is now a much more pleasant place to work in and it no longer leaks. There are still a few minor jobs to be completed but these may have to be postponed until the Spring.
Accordingly, I am appealing to members for donations towards this major project which should keep the Observatory in good shape for the next 35 years at least. If you would like to donate to this worthwhile cause, please make cheques payable to the Hampstead Scientific Society Astronomy Section and send to : Julia Daniels (Section Treasurer) 25 Village Road Finchley N3 1TL. All contributions will be gratefully received.
Members will be aware that during 2012 we lost two of our long standing members. Alfred Oppenheimer and John Hayden sadly passed away. We wish to convey our sympathy to their respective families and friends particularly at this time. Obituaries were posted on the Society's web-site.
Members will also be saddened to hear that Sir Patrick Moore passed away at 12:30 pm on Sunday December 9th at the age of 89. Patrick had a long standing association with our Society. No one has done more to encourage the study of astronomy in this country. He will be sadly missed by all who knew him.
When our Observatory was built in 1910, the skies above it were graced by the appearance of two major comets, Comet Halley and the Great Daylight Comet. As it transpired, Comet Halley was not a particularly bright comet and the media (the press) at that time confused the two and thought the Gt. Daylight Comet was Halley. On its return in 1986, Halley was a disappointing object in the northern hemisphere but its arrival was again overhyped by the press who still managed to confuse it with the Great Daylight Comet of 1910. This resulted in over 1000 visitors queuing in freezing temperatures at the Observatory to observe the faint smudge that was Halley's Comet and they were not at all impressed.
During the latter part of the 20th century we had a good crop of bright comets but none to compare with the Great Daylight Comet of 1910, none that could be described as a Great Comet. In the 1950's we had two naked eye comets Arend-Roland and Mrkos. In 1965 Comet Ikeya-Seki reached magnitude minus 10 before breaking up into 3 pieces.
1973-4 saw the disappointing Kohoutek but a year later comet West attained mag. -3 and could just about be seen in daylight. In 1996, Hyakutake sported a tail of 80 degrees and was circumpolar but poorly observed due to bad weather. 1997 saw the best comet for years – Hale-Bopp a comet that was visible to the naked eye for 18 months and which attained a mag. of -1. In 2007, McNaught was a wonderful sight in the southern hemisphere, also in 2007 Holmes unexpectedly flared up and reached mag. +2.8 its dust cloud expanding to twice the size of the Sun and was well seen in the northern hemisphere as it was almost on the zenith in Perseus.
Now, if we are really lucky, there are two comets to look forward to in 2013, one of which, Comet ISON, could become a Great Comet and earn the title 'Comet of the Century'.
In 2013 the first prospect however is Comet C/2011 L4 pan-STARRS which was discovered on Sept 4th 2012 from Puerto Rico. Early calculations suggest that comet pan-STARRS could attain mag. 0 when it approaches the Sun to within 28 million miles in March 2013. At this time it will be fairly low down in Pisces, just below the Gt. Square of Pegasus close to the western horizon after sunset. If all goes well, it has the potential to become a striking naked eye object in the evening skies next Spring.
But it is Comet ISON that could just become the brightest comet to grace our skies since 1910. ISON was discovered on September 21st by astronomers using the International Scientific Optical Network telescope (ISON) in Russia. At present, it is situated beyond the orbit of Jupiter and is a very faint object at about mag. +18 in Cancer. Preliminary calculations indicate that it could approach the Sun to within a distance of just 2 million kilometers on 28th November 2013 at which time it could attain a magnitude of minus 11 to -16, the latter is 15 times brighter than the full moon (mag. -12.7) and it could easily be seen in daylight! Moreover, during December 2013, ISON will be moving upwards through Ophiuchus into Hercules, so it will be well placed for northern hemisphere observers and it could be visible for months.
Comets fall roughly into three main classes: short period, long period and single apparition. The long and short period comets are permanent members of the Solar System termed periodic. Such comets can be expected to become less spectacular with the passage of time as their frequent close approaches to the Sun cause their volatiles to sublime and deposit dust on to their crusts. After many solar passes, their crusts thicken and their volatiles become exhausted – they simply 'wear out' and become indistinguishable from asteroids. They also distribute dust along their orbits as well; it is dust from Comet Swift-Tuttle for example, that causes the annual Perseid Meteor shower. Short period comets are those with periods less than 200 yrs. The comet with the shortest period of all is Encke at 3.3 years and is responsible for the Taurid meteor shower.
Long period comets have highly eccentric orbits with periods ranging between 200 years to thousands, even millions of years. Hale-Bopp for example will not return to the vicinity of the Sun for 4000 years and McNaught won't be seen again until 92,600 years have elapsed.
The non periodic comets or single apparition comets come from the distant reservoirs like the Kuiper- Edgeworth belt of the Oort Cloud. Such comets can appear suddenly without warning, approach the Sun and are never seen again. They have extremely hyperbolic trajectories.
As comets travel through the Solar System, their orbits can be perturbed by the giant planets such as Jupiter. That mighty planet has a whole group of comets associated with it, some with periods in resonance with Jupiter's 12 year orbital period. On its last pass, Swift-Tuttle was perturbed and arrived 10 years later than predicted and some of us remember well how Shoemaker-Levy 9 was fragmented and subsequently swallowed by Jupiter with dramatic results in July 1994. We watched night after night enthralled by the spectacle as the 15 fragments of the comet ploughed into Jupiter's cloud belts leaving huge dark scars in their wake.
As comets get closer to the Sun they can be perturbed by the inner planets and as they warm up the gases streaming from their nucleus can act like little jets, subtly altering their orbits. It is believed that this jetting may have contributed to Swift-Tuttle's late arrival on its last visit.
There is also a sub-group of comets termed sun grazers which fly close to the Sun and can occasionally fall into it. At its closest approach, comet ISON will be just 2 million kilometers from the Sun so there is always the possibility that it may not survive its perihelion passage. Coming so close to the Sun, it may simply evaporate or violent outgassing may cause the nucleus to fragment.
There are many factors that can affect comets as they are drawn towards the Sun. So what are the chances that ISON will actually be a 'Great Comet' and that pan-STARRS will put on a decent display? Both are long period comets so they should contain masses of volatiles, and as they are new arrivals from the Oort Cloud, they will not have had their icy crusts thickened by large quantities of smothering dust built up over many apparitions. This all bodes well but as we know from past experience, comets are very unpredictable. As David Levy once said: "Comets are like cats, they have tails and they do what they like." As a long term cat owner and avid comet watcher, I couldn't have put it better! Let us hope that ISON lives up to early expectations and if it does we will be in for a very busy time at the Observatory – just as well that we have finished the renovations in good time.
Peter R Wallis
Are our rivers and lake fish now on the pill? It would seem so as the European Commission proposes new regulations which would limit the concentration of ethynyl oestradiol, EE2, the pill's active ingredient, in rivers and lakes. The problem is that this hormone causes male fish to become more feminine, threatening the survival of the species. One study found incipient effects in fish living in surface water with a level of EE2 of one nanogram per litre. The EC proposed in January a limit of 0.035 ng/l, "to play safe and cover other species". This level may be guilding the lily, as has been argued by water and pharmaceutical companies.
The EC also proposed limits for diclofenac, an anti-inflammatory drug sold also as Voltarol, which is commonly used to ease the pain of osteo-arthritis in humans. It can disrupt cell function in the liver and gills of fish; it is already notorious for devastating vulture populations in Asia.
The EE2 standard above was planned to be discussed by the European Parliament's environment committee on 28th November and, at the time of writing, may well be rejected because some very expensive estimates have been made for upgrading water treatment plants. For example, DEFRA has suggested £26 to £30 billions, though this was based upon a more stringent standard of 0.016 ng/l which may be ten or more times lower than is necessary, and assumed the expensive treatment technology of granular activated carbon would be necessary in all cases. As you can imagine there is much argument between the interested parties, water companies, pharmaceutical companies, customers and governments on one side and environmental scientists on the other. The latter say that the case will only get stronger and there could be a disaster for wildlife if the opportunity to ensure clean water is missed.
Indeed it could also affect our own health if we have too many drugs in our drinking water; for example anti-biotics could encourage anti-biotic resistance in bacteria.
Oh dear! I have been suffering from a very painful spinal disk problem and sciatica for the past three months. Part of the treatment included the use of diclofenac the non steroidal anti-inflammatory mentioned in the above text. I really had no idea that in my small way I was contributing to the devastation of the vulture population in Asia, particularly as the drug had no appreciable effect on my condition. Accordingly, I will stop using it immediately and offer my apologies to the vultures of Asia. I would also urge the manufacturers of this particular NSAID to include a caution on their leaflet of recognizable side effects.
The first meeting in 2013, will take place on Thursday 17th of January, when Professor Paul Leonard from Brunel University, will lecture on: The Uses and Abuses of Nuclear Energy. I hope to see you at the meeting.
Last updated 27-Jan-2018