Stargazey Pie, August 2005
Antony McEwan's monthly digest of HAS happenings.
I always think of August as a stepping-stone month. The skies begin to gradually darken and by the end of the month we have several hours of prime sky-watching darkness. It’s a time of looking forward to the highlights of autumn: the cooler mornings and evenings, the Moon rising higher in the sky again than it did in the summer, the thrill of using your headlights when driving home late in the evening and the disappearance of the Midgies! August is traditionally a month of great astronomical society meetings too, as typified by one that took place on Tuesday 2nd at the Green House in Inverness. It started as always with Chairwoman Pauline and this month’s notices:
HASBBQ&SP. The barbecue in Simon Urry’s garden at Muiryden on the Black Isle will take place this month on Saturday the 27th from 3.30 in the afternoon, followed by a Star Party. It will be weather-dependant so if you are not sure if it is still on, or require further information, please telephone Simon; contact details are on the back of the HAS programme. Please let Pauline know if you will be attending, even if you are only a ‘maybe’.
Science Festival. If you think you can help with the Science Festival on Friday 11th November or Saturday 12th November, please contact Maarten. Volunteers only need to help out for half a day, and on the Saturday can listen to the talks for free! The organisers are looking for help in the following areas:
Volunteers to help look after visitors to the Festival on Friday 11th, when schools will be visiting, and on Saturday 12th November, when the Festival is open to the general public.
Speakers who could give a half hour presentation on Saturday. The subject is astronomy and/or cosmology and should be pitched at a level of understanding suitable for the general public and children.
A manned stand from our Club. It must be set up on Wednesday 9th but only needs to be manned on Friday and Saturday then taken down on the Sunday.
On Friday and Saturday there will be access to both the 2.4m Faulkes Telescopes in Hawaii and Australia. A team of capable people are needed to take responsibility for the telescope activities. They would be required to design an observing schedule, plan the activities that would take place and then carry them out over the two days. This should be done in such a way that it gives the audience a chance to see astronomy in action.
Perseids Perhaps? The Perseid meteor shower reaches its peak on Friday 12th August and we are planning to be at the Culloden Battlefield car park at midnight (Friday night, Saturday morning) to observe it. The Perseids regularly give a good showing, with many bright and long-lasting meteors, so let’s hope they continue the trend this year. If the sky is patchy then the event will probably still go ahead, but if completely cloudy or wet then it will not. Contact Pauline for details, but please- not late at night or in the early hours!
Scope-Night! Saturday 13th will see the first of this season’s observing sessions- with a twist. Last month we had the society Equipment Night, so for this observing session we invite members to bring along their own telescopes and show them off again- this time under the night sky! This will be a great occasion to see how different types of telescope perform on different types of object. The Moon will be visible to start with, but will be very low in the sky. The session will start at 9.30pm, contact Antony or Rob for details.
Earth-2? On Wednesday 31st August at 9pm on Radio 4, there will be a program called ‘The Goldilocks Planet’. It is about the search for life on extrasolar planets and the questions, particularly for Christians, which may be raised once life is found.
It’s Chile here. A Chilean travel agent has been in contact offering astronomy-oriented tours. These include an 8-day trip to the north of Chile to visit the Paranal Observatory, the site of the ALMA project (which is the building of the largest radio Observatory in the world), and explore the Atacama Desert, site of NASA Mars experiments. A customised tour is being created for Ewell Astronomical Society and the same has been offered to us if we so wish. Perhaps we shall wait until Ewell Astronomical Society has come back in one piece. However, if you are interested the website is www.quasarchile.cl. Please note we are merely passing on this information: we cannot guarantee the services offered by this company or the validity of the company itself, and definitely cannot guarantee that the clouds won’t follow you to Chile if you go.
Feeling SAGgy? Then the Scottish Astronomers Group Weekend, 23rd to 25th September, may be the ideal pick-you-up! There are many talks and events planned for this occasion, and there will be plenty of chances to meet up with fellow amateur astronomers from other parts of Scotland. You may have received a programme in your email from Pat Williams, to whom we would like to offer our thanks for organising much of this event. If you would like further information, a programme, or to volunteer to help out at the event, please contact Pat.
How Extraordinary. Chairwoman Pauline had the following to say about our progress with the new observatory project: "After consultation with many members and listening to their concerns, and after a Committee meeting where the new observatory was discussed in detail, all options considered, and running costs looked at, it is felt that we must go for an observatory that is more manageable both in terms of costs and commitment. Therefore we do not need to become a Limited Company but still require Charitable Status for which the Constitution must be updated, and this is why we are calling an Extraordinary General Meeting in September. The situation has changed as new information has come to light and we have had a number of setbacks, all of which have to be taken into account when trying to do what is best for the Society. Although we now feel we are making progress, we haven't yet reached the end of the rocky road, but hope you will bear with us as we negotiate any further bumps and potholes". There is a letter announcing the EGM attached to this issue of Stargazey Pie in Word Document format. Simply open the attachment and read though it. If you cannot open the attachment please contact myself or Pauline and we will arrange to send it in a different format or post it out to you. Further to this, members will be receiving a draft copy of the proposed new Constitution by email in the next few weeks. Please take the opportunity to read through the draft so as to be aware of the proposed changes before the EGM in September. Please keep an eye on your Inbox!
Eyes on the Skies. August is a month full of promise and by the middle of the month we will actually experience brief periods of astronomical darkness again. By the end of August these will be four hours long and getting longer.
The summer constellations of Lyra, Cygnus and Aquila are high overhead and contain such wonders as the Ring nebula, the Veil nebula, North American nebula, and some beautiful double and multiple stars including Albireo and Omicron Cygni in Cygnus, the famous ‘Double Double’ Epsilon Lyra, and many other showcase objects. Better views will come with the darker nights, but it doesn’t hurt to have a look for them before then.
When the dark nights do return we will find ourselves looking up into a late summer sky full of Messier Objects, from the rich hunting grounds of Sagittarius in the south, through Ophiuchus, Hercules, Aquila, Lyra, Cygnus and Cepheus to Cassiopeia and Perseus in the North. The open and globular clusters, supernovae remnants and planetary nebulae scattered throughout these constellations are sprinkled against the backdrop of the Milky Way, the edge-on view of our own galaxy that stretches across the whole sky at this time of year. If you are blessed with a clear dark night it is well worth travelling out to a site devoid of artificial lighting to see this splendid spectacle laid out above you. Any form of optical aid will show you many wonderful star-fields, but even a naked-eye view will be memorable.
As mentioned in the notices, the Perseid meteors are coming, and they should be active through the month but will peak on the night of the 12th. They are predicted to be plentiful, swift and bright so are well worth taking some time out to go and see, though they tend to increase in number in the pre-dawn hours so you may wish to prepare for a long session! No equipment is required- just a dark site and something comfortable to sit in like a deckchair, but be warned- it gets cold at night sitting still so dress for winter. Fingers crossed that the Perseid observers at Culloden on the 12th have clear skies and a high meteor count.
The Main Events
Moons of Mars by John Rosenfield
John Rosenfield, a member of both the Highlands Astronomical Society and the Aviemore History Society, gave the first presentation, entitled ‘The Moons of Mars’. Most people have heard of Mars’ two little moons, Phobos and Deimos, but not a lot of people know much about them.
Amazingly, Jonathon Swift seemingly announced their existence in his novel ‘Gulliver’s Travels’ in 1727, well before the moons had been officially observed by Asaph Hall! In the novel Swift described their motions through the Martian sky in remarkably accurate detail, including the fact that due to its orbital complexities, Phobos’ month is actually shorter than its day! How did Swift so accurately predict the existence of these moons? He was certainly an intelligent man (most satirists are) and would have known about Kepler’s laws of planetary motion. It is possible that he simply extrapolated from the fact that Earth had one moon, Jupiter had four, and so the planet in-between must have two to maintain the mathematical equilibrium! Ultimately it is simply not known how he arrived at his conclusion.
The moons themselves are equally mysterious. Phobos, the inner moon, measures 27 x 21.6 x 18.8 km, and has the lowest orbit of any moon in the solar system at under 6000km. Many consider this orbit to be unstable, and suppose that Phobos will eventually impact the surface of Mars itself. This opinion is apparently still open to debate though!
Deimos is the outer moon, with an orbital radius of 23,460km, so is a lot more distant than its companion, Phobos. Deimos measures 15 x 12 x 10km, again very small, and both moons are very obviously non-spherical, leading to the belief by many that they are actually asteroids captured by Mars’ gravity. Like everything else relating to the Martian moons, this is also up for debate, with different groups of scientists taking different sides!
John gave a very informative talk, referring frequently to Jonathon Swift’s work, but also telling us about Asaph Hall’s discovery, and subsequent observations of, the two moons. The moons were named after two of the sons of Ares, whom Mars traditionally represents in the night sky: Phobos meaning Fear, and Deimos meaning Terror or Dread. Maybe this fear-inspiring nomenclature contributed to the Russians associating the moons with several Mars mission failures in the sixties and seventies and to them believing that Phobos was actually a Martian Space Station!
The scientific debate about the origin and fate of the two moons will continue, but one thing was definitely not up for debate; we all enjoyed learning a little more about two of the most unusual moons in the solar system- thanks to John Rosenfield.
Coronas and Comets by Eric Walker
Eric Walker is known as one of the Society’s keenest Astro-photographers (celestial shutterbugs even) and continues to delight us with not only his images, but also his infectious enthusiasm. It has only been a few years since Eric took up the camera and telescope to capture visions of the skies above Conon Bridge, but the quality of his pictures has very quickly reached an enviable level and they regularly appear on the society’s website gallery page as well as on his own website.
For this presentation Eric took us on a journey through the Earth’s atmosphere, past the Moon, the Sun and the outer planets, to the vast dark reaches of the deep sky. His pictures of atmospheric phenomena were fascinating, along with the explanations of such things as Alexander’s Dark Band which is seen as a darkening of the sky between two rainbows. Eric showed us other impressive (yet fairly common) features such as Sun-Halos and Sun-Dogs, as well as the ever-enchanting Noctilucent Clouds and beautiful aurora, which are some of the reasons we are so lucky to live at a latitude in the mid-fifties.
Venturing out of Earth’s realms, we visited the Moon, to see some excellent high contrast pictures of various areas of its magnificent desolation. When we look at the Moon in the sky it really seems quite large, but one of Eric’s pictures showed that its apparent diameter is in fact quite small. The picture in question showed the crescent Moon in the same field as the Pleiades, which appear to be about three times larger than the Moon! Other pictures showed close-ups of various terrain features on the Moon, including the Appennine Mountains and the famous craters Plato, Aristillus, Archimedes and Eratosthenes. Some of my favourite moon-shots showed Vallis Alpes (the Alpine Valley) and Rupes Recta, the famous ‘Straight Wall’.
After a couple of very sharp shots of Sunspot groups, we perused images of Saturn and Jupiter, including a terrific series taken on 12th May 2005, which showed transits of the moon Europa and its shadow across the face of Jupiter. The Great Red Spot was also quite clear and the speed of its progress across the planets face was evident, illustrating Jupiter’s fast rotation period of about 10 hours.
Once past the gas giants we were treated to pictures of some of the best showcase photographic objects in the sky, including M31 the Andromeda Galaxy, the constellation of Orion, M42 the Great Orion Nebula, the Double Cluster in Perseus, and once again Eric’s favourite: the Pleiades! Eric also snapped the recent visit by comet Machholz, capturing it on one occasion against the backdrop of an impressive auroral display. Other shots were turned into negative images in an attempt to show the comet’s rather shy tails.
It was very enjoyable to see such a large number of images presented as a journey from Earth into space, with interesting and concise explanations of the objects and phenomena we were viewing. ‘The journey continues,’ was Eric’s final comment, and we look forward to seeing future images recorded on that journey.
Next Time. The September meeting will take place on Tuesday 6th at the Green House at 7.30pm. The meeting will have Extraordinary General Meeting status, so be sure to attend if you wish your opinion to be heard in the Constitution discussions. The main event will be a talk entitled ‘Space Medicine: Challenges of Microgravity to the Human Body’ and will be given by Alyson Calder. I would expect there to be plenty of gossip about everything that happened at the Barbecue and Star Party on 27th August as well as information about the forthcoming Scottish Astronomers Group weekend in late September. Add to this the Breakout Groups and the cosmic cuppas, and it’s going to be a Mustn’t Miss Meeting! Unfortunately I WILL miss it, as I’ll be on holiday, but at least I’ll have a telescope with me!