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Stargazey Pie March 2007

The Highlands Astronomical Society meeting on 6th March had a little bit of everything: creeping shadows (lunar eclipse), exploding stars (Going Nova 2), hot and cold running water (tea break), fame and fortune (interest from the makers of a TV programme and contributions towards our funds) and even the stars falling from the sky (the subject of our main presentation)! What more could anybody ask for? Certainly plenty of people turned up to experience this gamut of human experience. It all started with the notices, read for the penultimate time by Chairwoman Pauline Macrae:

  • Thanks! To Allan Thorne, for his wonderful gift of the compass and sundial, which he presented to us at the last meeting. It will go in pride of place in our new observatory. Thanks also to Trina Shaddick, for her wonderful gift of standing in for Pat Escott to perform Treasuring duties when Pat’s away!
  • Stargazing Events. These will take place from 8pm to 11pm on the dates listed below, assuming the weather cooperates. If in doubt, contact the host by phone, using the home number before 7.30 and the mobile after 8pm. Please note that Pauline Macrae’s home number will not be available from 16th Feb to 23rd March.

Friday 9th Mar..... Pauline Macrae
Saturday 10th Mar..... Pauline Macrae
Friday 16th Mar..... Antony McEwan
Saturday 17th Mar..... Maarten de Vries
Friday 6th Apr..... Antony McEwan
Saturday 7th Apr..... Dave Hughes

  • AGM Looms. The constitution demands that we inform you of the impending Annual General Meeting, which will take place on April 3rd at the usual venue. The positions of Chairperson and Treasurer become vacant, though Pat Escott has agreed to stay on as Treasurer. If you have any nominations for someone to fill these posts please send the name of the proposed, proposer and seconder to Pat Williams, although this can be done in person at the AGM. If anyone is proposing any changes to the Constitution, please let Pat Williams have them in writing 14 days before the meeting. This will create a lot of extra work regarding our charitable status though, so it is fervently hoped that none are proposed! Our AGM’s are renowned around the world as being events of excitement, intensity and wonder, so please come along as your input will be required and valued.
  • Going Nova 2! This will take place on the 22nd, 23rd and 24th March. The Thursday will be a day at Horizon Scotland in Forres, with sessions about various ways in which the future of our area can be shaped. Friday will consist of workshops for schools and Saturday will be for the general public again. Topics include Fuels of The Future; Space Tourism and Space Flight; Fuzzy Logic – applied to distilling; The Moon and Deep Space Imaging; Robotics – Powered Flight and Miniaturisation; Engineering Design – taking examples from nature; Quantum Physics; Food Science. Note that there are daytime and evening sessions on the Thursday and it is essential to book your place for these. Friday will consist of workshops for schools. In the evening the Moray Gaelic Choir join Howie Firth in Garmouth Village Hall for the story of the Mesolithic and Neolithic peoples of Moray. Tickets will be available at the door. Saturday will be for the general public and the free presentations include:


·10:15 Pictures from Deep Space
·11:30 Exploring the Moon
·12:30 Believe It Or Not
·1:15 Pictures from Deep Space 2
·3:30 Fire and Ice: a traveller’s guide to the solar system

You don’t need to register for the Saturday events, and can stay all day if you like. There will be plenty of volunteers to show you around, and there will be a special corner for the young budding scientists! Thank you to everyone who has volunteered to help, and more information is available on the Going Nova website and from Maarten.

  • First Day Covers. The first day covers of the Sky at Night stamps on Highlands Astronomical Society envelopes have now been sent out to all those that asked for them. This is a bit of a surprise, as it was intended that Simon Urry distribute them at the March meeting, but apparently the Post Office in Edinburgh didn’t take note of our wishes. When we take over the world they may well regret that. HAS have produced official inserts for the packages with information on the objects depicted on the stamps, so if you need one please contact Pauline. If you are still waiting for your first day cover please contact Simon.
  • People Power! There is an online petition to ask the Prime Minister to ensure that all exterior lights are shaded to direct their light downwards, so as to prevent light pollution obscuring the beauty of the night sky. Click here to sign it now! There are over 2000 signatures on it so far, so please go ahead and add your name to the list of concerned citizens. Up the Revolution!
  • Fame! We have been contacted by a Gaelic TV programme about a pilot for filming the night sky up in the Highlands, linking it in with past, present and future astronomical observatories and the importance of the night sky through history. They would like to come up to our observatory and film us having a star party on Friday 16th March. I hope as many of you as possible will come along that evening. Rain and impenetrable cloud cover hasn’t yet been spoken about…
  • Observatory Update. We are still waiting for the soakaway tests to be carried out before we can apply for planning permission. John Gilmour has agreed to be Project Manager for the new observatory. I (and others) have been posting out brochures and letters to local businesses looking for investment in our project, but only one response has been received so far. That was from the Bank of Scotland and was negative. Forms for the name on the plaque scheme are still available, whereby you can be named as a sponsor on a plaque on the wall for only £25. Also, Maarten has been beavering away hunting down funding and has secured £250 and another £300, along with a promise of £750 and has another £1000 that he is chasing. On top of that, Lynn Robinson gave us a cheque at the meeting for £500 towards the needed funds! Very welcome and thank you very much Lynn!
  • Seeing Stars. The latest Seeing Stars article is by Maarten de Vries and is all about lunar eclipses. It’s called Back To The Moon and is available to read on the website here. You may also have caught it in the Inverness Courier on Friday 2nd March.


Total Lunar Eclipse

Apologies were expressed for the failure of the Society to organise an official observing session for the total lunar eclipse that occurred on the night of Saturday 3rd March. Fortunately, many of you took it upon yourselves to observe the phenomenon, and even photograph it! A selection of excellent photographs was shown on the large screen, with offerings from Maarten de Vries, John Gilmour, Alan Tough and Eric Walker. The picture showed the variations in colour as the shadow swept across the face of the Moon very well, and Eric’s montage of images showing the whole event gave an impression of how the different stages appeared in relation to each other.


 

 

The Main Event
‘The Night The Stars Fell’ by Brian Kelly


Brian Kelly was for several years Dundee's City Astronomer, and in charge of the city's public Mills Observatory. He is a part-time lecturer for Dundee University's Centre for Continuing Education where he teaches classes on astronomy (and occasionally on weather and climate) and he is a keen amateur astronomer, with a particular interest in naked eye and binocular observing. Brian currently works as Education and Community Outreach Officer for Dundee Heritage Trust, which runs the Discovery Point centre and Verdant Works jute museum.

‘The Night The Stars Fell’ is quite a dramatic title, and as you can probably guess the talk was all about meteors. Certainly in historic times a really strong meteor shower would make it appear as if the stars were quite literally falling from the Heavens. It is only relatively recently (in astronomical terms) that we have realised exactly what a meteor is and why we are subject to these nights when all the stars seem to fall.

Brian started off by explaining some commonly confused terms to us. A meteor is what we think of as a ‘shooting star’, and is a small piece of matter that has burned up in our upper atmosphere. The friction caused by this causes the air along its path to heat and glow (becoming ionised), causing the commonly seen meteor trail. Most meteors are about the size of a ground coffee granule! A bolide is usually a slightly larger fragment, that penetrates deeper into the atmosphere and breaks up or explodes while still airborne. (Quite frequently seen from the Black Isle, by the way!) A meteorite is a fragment that has survived the journey through Earth’s atmosphere and has landed on the surface. Frequently the media mix up the terms meteorite and meteor, so now we can all write in to our newspapers and TV stations to correct them! Finally, a meteoroid is an object out in space that has not yet reached our atmosphere.

With these definitions in mind, it was then time to look at how meteor storms had been recorded throughout history. The Chinese have kept very methodical records of meteor storms for a very long time, as have many other cultures. They were surprisingly useful to astrologers, who could easily portray them as portents and signs that would encourage or frighten their sponsors or rulers. Remember, we now go out at night and understand that a meteor is an object that has travelled through space and burned up in our atmosphere, and are probably quite blasé about them. But in ‘olden days’ such a thing would have been an awe-inspiring phenomenon, and quite often drawings and reports of these events are embellished with pictures of dragons, gods battling in the skies, and other supernatural paraphernalia.

Up until the 17th century, the generally held idea was that the Earth was the centre and imperfect, while everything ‘above’ the Earth was Heavenly, pure and perfect. It was sometimes suggested (by Aristotle for example) that these bright, brief flares were caused by some kind of effluent from the imperfect Earth rising up towards the Heavens and igniting, then being forced back down again. This vindicated the idea that the Heavens were unchanging and permanent, and that such outrages against the cosmic order could only come from Earth itself.

Thankfully, science intervened and Edmund Halley challenged these ideas in the 17th century. He applied logical thought to the problem, and particularly to the case of an observed meteor that had a very long tail and had been observed from many locations at the same time. Using the data from the observations, Halley calculated that the meteor must have been at a height of 80 miles above the Earth, and its velocity to be higher than the escape velocity of the Earth, so concluded that it must have come ‘in’ to Earth’s atmosphere rather than being thrown out from the Earth. This work was continued by two German scientists who continued to use observations of the same meteors from different sites, applied parallax calculations to them and found that most were between 50 and 60 miles high and travelled at many tens of miles per hour.

At the end of the 18th century, it was realised that the meteors seemed to come from particular points in the sky, and that these points, or radiants, moved across the sky as the night progressed, travelling with the background constellations. Another groundbreaking realisation was that the very strong showers seemed to repeat themselves over set periods of years, and so could be predicted. The periods of the showers were found to be more accurately aligned with sidereal time, or the movement of the stars around the Earth, rather than the movement of the Earth around the Sun. This really clinched the fact that meteor showers were extraterrestrial in origin.

We now know that meteor showers are often caused by the Earth’s passage through the trail of debris left behind by passing comets. This was not always known, and it was the work of Giovanni Schiapparelli (of Martian canelli infamy) in 1862 that made the connection after his observations of comet Swift Tuttle and the Perseid meteor shower. This was further confirmed by observations of comet Temple Tuttle and the Leonids in 1866, the very year that the comet was first discovered!

In the second half of his presentation, Brian introduced us to a number of prominent meteor showers that we should all be able to enjoy, and talked about which comets or other bodies actually cause them. It is still unknown as to what objects cause some of the showers, for example the Quadrantid shower. The radiant for this shower was in the long gone constellation of Quadrans Muralis that occupied space in the area of Draco, Hercules and Bootes. The shower peaks usually on January 4th, and remains one of the lesser observed ones, perhaps for obvious reasons!

Other showers are regular performers, including the Lyrids in April, Perseids in August, Leonids in November, Orionids in October and many more. The only things that can detract from meteor observing are an unfavourable lunar phase or poor weather. It is an easy project to do, and the only equipment needed really is an accurate timepiece (stopwatch useful), pen and paper, deckchair and blanket and your choice of food and drink to keep you going! There is much information about meteors on the Internet, along with reports of observations and advice on how to go about seriously observing them. A visit to the British Astronomical Association website would be a good place to start.

Perhaps one highlight this year may be the Perseid shower in August, as we are lucky enough to have a New Moon on the peak date of the 12th, which bodes very well indeed – weather permitting of course!

Brian’s talk was full of useful information and very well delivered. It really conveyed his enthusiasm for this particular aspect of astronomy, and I think may have sparked some more serious interest in these ‘falling stars’ amongst the Society’s members. Thanks for coming along Brian, and don’t worry: to us you’re still a ‘rising’ star!

 

Highland Skies – March 2007

If you have recently looked into the west after the Sun has set, you will probably have noticed Venus hanging about 13 degrees above the horizon like a blazing celestial lantern preparing to ward off the darkness of winter night. Venus is currently shining at magnitude –3.9 and is on the far side of the Sun to us, showing a ‘phase’ of about 85%. Venus will reach its greatest elongation away from the Sun in June, before starting to get closer again. It will not become a morning object until August, so we have plenty of time to enjoy her evening light.

This month Venus serves another purpose. It serves as a handy signpost to a nearby comet – Comet 2P/Encke. This comet will brighten from 13th magnitude to (hopefully) 9th or brighter as the month progresses, and it can be found 9 degrees northwest of Venus on the 15th. This comet has a fairly short period of just over three years, and its orbit is known very accurately. Some of you may remember viewing an Encke comet a few years ago using our 12” HASDobs telescope at the Culloden observatory, when it was generally thought to be a bit underwhelming. If this is the same one (I think it is), and if it does continue to brighten as predicted we may have a better view this time around, though we will have its low altitude over the horizon to contend with.

Getting away from the horizon, the giant constellation of Leo is rising now, and it is about time to start searching its environs for the many deep sky objects contained therein. Four spiral galaxies included in Charles Messier’s list are to be found in Leo; M65 and 66, and M95 and 96. There are many other NGC galaxies too, and several double stars, including alpha Leonis, known as Regulus or ‘The Heart of the Lion’. The galaxies will all be visible in small telescopes, even down to 3” refractors, but will show more detail in larger apertures.

Right in front of the ‘Sickle’ asterism that makes up the forequarters of Leo, Saturn shines brightly, set apart slightly from any stars of comparable brightness. As the angle of its rings is becoming more edge-on to us, it becomes more and more of a challenge to see detail within them, including the Cassini Division. When the rings are wide open to us, the division is fairly easy, and they can be glimpsed at fairly low powers of 50x or so, even in a small telescope. But as the angle closes, it can take more magnification to detect, and aperture seems to become more important as well. This is an interesting time to take the Cassini Challenge – try to see just how low a magnification you require to make out the division. It may vary with different telescopes, and of course the ‘seeing’ or stability of the sky is always an issue when trying to see the gap, but with Saturn being so high in the sky now it should help to equalize this somewhat.

Once you have successfully detected the division, maybe you could drop a line about your experience onto the website message board, giving details of the telescope and eyepiece used, seeing conditions, etc. There will be a special ‘Cassini Challenge’ post on the board for you to add your replies to, and I hope to see lots of input there in the months to come!


Next Time. April’s meeting, on the 3rd, will be the Society’s Annual General Meeting. It will be at the Green House as usual, and will start at 7.30pm. Please do come along to hear the changes and updates that are unveiled, and of course to discover who the new Chairperson will be!


As well as all this, there will be the usual mixture of chitchat, outbreak groups and tea-consumption. All the fun of the fair. Or astronomical society anyway…


Until April 3rd, Dark Skies!

 

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