Stargazey Pie February 2008
February’s HAS meeting had some real highlights. Some of the feedback from the members about how the Society should progress was discussed. There was a great update about the gas giant Jupiter, a return to the Breakout Groups, and another excellent demonstration of the Stellarium planetarium software showing us what can be glimpsed in February’s night sky. There was even more, but as they say: you had to be there… Before the main talk, the notices were read by Eric walker:
- Immortality Still Available. Your low-price Immortality special offer is only available for another month! A contribution of £25 towards the New Observatory funds will get you a mention on the plaque that will go inside the observatory for all to see over the next few millennia. Contact Pat Escott if you would like to be remembered forever.
- Moon Phase Postcards. Some Moon Phase postcards are still available and can be purchased from Pat Escott for the ridiculously cheap sum of 100 pennies each. Go on, splash out – you need to know when the Moon is around so you can plan your lunar observing sessions or apply your lune-cream so that you can go out safely under its glow.
- Seeing Stars. The latest Seeing Stars article is by Rhona Fraser and was published in Friday 1st’s edition of the Inverness Courier. It features Canis Minor, Cancer, the Winter Triangle and the forthcoming lunar eclipse.
- HAS AGM. The Society’s Constitution dictates that you should now be informed that the next AGM will take place at the April meeting, on the 1st of that month. No joke. You may now consider yourselves so informed. A DVD will be shown after the main business has been attended to.
- March. The Society’s March meeting will take place at the NTS Visitor Centre at Culloden . We will have Neil Bone, Director of the BAA Meteor Section, giving a talk on his favourite subject: Meteors! We would like a good turnout at this meeting as we would like to assess the membership’s feedback about the venue. If you need transport from Inverness to the Visitor Centre, please contact John Gilmour.
- Competition. This year we will be holding a competition to select the photographs for inclusion in the 2009 HAS Astrophotographic calendar! The competition will be judged by HAS members and will feature some exciting prizes (about which, discussions are under way). Eric has kindly agreed to run a series of workshops for members interested in developing (no pun intended) their photographic and image-processing skills over the next few months. Please contact Eric directly if you are interested in participating.
- FAME! Thanks to the HAS members who, at very short notice, attended the making of a Gaelic TV programme about astronomy in the Highlands, at Eric’s house on the evening of Friday 25th Jan. Despite the foul weather, they really did make the cameras believe they were observing Mars and the Milky Way! The programme is due to be broadcast later this year and will discuss the importance and impact of astronomy on life in the Highlands and Islands, from ancient times to the present day. The TV company, STV, donated £100 towards the observatory funds!
- Dark Skies Event. There will be another Dark Skies Scotland event at Strathnairn Community Woodland (Farr) on Fri 22nd and Sat 23rd February. Assistance is required from HAS members for this event, so if you are interested please contact Pauline for more information.
- History talks. John Rosenfield is presenting a talk to the local History Society at Rothiemurchus Tennis Club on Tues 12th Feb at 7.30 for 8.00pm. The first part is a TV programme from a few years ago, asking; 'Why do the Cairngorms look like they do today?’ and the second part is John’s slide-show of Loch Morlich Youth Hostel, 70's and 80's, where he grew up. If anyone wants to come, they are most welcome.
- The Lost Language of The Stars. Heather Connie Martin’s latest book on the ancient carved Pictish symbols representing astronomical constellations has now been published, and a sample copy has been sent to Eric. If you would like to see it or order your own copy, please contact him directly.
- Monthly Astronomical Events. Total Lunar Eclipse Thu 21 Feb; Space Shuttle Launch & ISS flybys Thu 07 Feb (19:45h) through Thu 14 Feb; Saturn at Opposition: Sun 24 Feb - visible all night and at its brightest and closest all year.
John Gilmour took the floor to give us a long-awaited observatory update. In the last few weeks things have really started happening, and John was there most of the time capturing the significant events with his digital camera!
He showed a PowerPoint presentation that incorporated his many pictures. The first was taken back in March 2007 and showed Pauline and Rob pegging out the site. We also saw the rubble from the site being removed in August 2007 and finally the very start of construction work in the early morning of 14th January 2008!
John’s pictures showed the ground being cleared and the initial work starting on the foundations and septic tank installation. They were taken from various angles, and we saw the positions of the observing platform, where the dome and telescope will be situated, and close by the observing station, where the computers, toilet and storage areas will be. The final pictures showed that the concrete had been poured for the observing platform and the floor of the observing station. See below - really exciting stuff!
A further piece of good news is that we have a date for the official opening of the observatory. Sunday 20th April will see the grand opening being performed by the Astronomer Royal for Scotland, Prof. John Brown! It is hoped that the observatory will already be fully functional by then, and possibly in use. The opening date is intended to come at the end of a week of special events organised by the NTS to celebrate the opening of their newly redesigned Visitor Centre at Culloden.
Be sure to keep that day free in your diaries!
What the Members Want
John then gave us a run down of the feedback that he has received from the Society members as a result of last month’s talk about future opportunities for the Society. At that time members were given feedback forms, and absent members had them emailed out to them. Despite this, out of a possible 84 replies only 39 have been received. If you have a feedback form that has not been returned, please do fill it in and send it to John so that the Committee can act on the ideas that the members want to pursue. If you did not get one, please contact John.
Some results from the feedback received were as follows. HAS Meeting Night choice: Tuesday 22, Friday 12, either/both 5. Night school classes and a schools education programme got 5 votes. Astronomy debates, a Society magazine and an annual exhibition got 7 votes. A separate beginner’s section got 8 votes. A Christmas dinner, summer barbecue and participation in a radio programme all got 10 votes. Regular opening of the new observatory to the public got 12 votes.
The five suggestions that got the most votes were:
Telescope Club or Equipment Group (15 votes, fifth place).
Star Parties and the setting up of BAA type subgroups (16 votes, equal third/fourth).
Children’s subgroup (18 votes, second place).
The suggestion with the most votes was:
Making astronomy trips (19 votes!)
Some progress has already been made with this surprising result. Andy Ferguson has been in touch with John and has passed on a possible itinerary for atwo-week trip to Arizona in the United States, including visits to Flagstaff and Kitt Peak observatories, Meteor Crater, the Grand Canyon, Las Vegas and more! If you are interested in finding out more about this (without actually committing at this stage) please let John know. Estimated cost of such a trip is thought to be £1300 to £1500 but it is really very early to be accurate with that.
John had already prepared a list of potential BAA type subgroups, including Deep Sky, Lunar, Solar, Telescopes, Aurora and others. He invited those interested to put their names on the appropriate list at break-time, and several did. It’s not been decided exactly how these subgroups will operate yet, but it is handy to have an idea of numbers of people interested.
Other suggestions that got some votes included an Astrophotography Workshop (which Eric is planning at the moment), out of town events (observing in Beauly, anyone?), an annual meeting with Sigma, school trips to the observatory (always on the agenda anyway), trips to astronomical events within the UK (e.g. ‘Astrofest’) and a quiz with two or more teams (because a quiz with only one team would be a little one-sided). John made the point that some of the more labour-intensive new activities would not be launched unless there were members willing to undertake the tasks involved, so if you’re in a volunteering mood, get in touch with John to discuss the future of the Society.
However, this is all based on the feedback generated by only less than half of the Society’s membership, so please get back to John with your feedback forms!
The Main Event
‘Jupiter’ by Pauline Macrae
Pauline Macrae will be known to many of you by now, having spent seven years as Chairwoman before John Gilmour took over last year. Pauline has a particular interest in planets, and has given several talks on them over the last few years. She also holds the position of Society Specialist in that subject. In real life Pauline works as an orthoptist and has been heavily involved in the new observatory project from the very start. Her favourite food is the cheese and kit-kat sandwich.
Pauline’s presentation included many superb images drawn from various sources on the Internet. One of the very first ones showed Earth alongside part of Jupiter to the same scale – the difference is incredible! Jupiter could hold approximately 1300 Earths. Pauline described Jupiter as being “a world covered with colourful, swirling clouds; its gaseous exterior concealing an exotic interior”. To start with the exterior was concentrated on.
Several wonderful full-colour images of Jupiter followed, showing the fantastic colours and structures of the various belts and zones that make up its gaseous atmosphere. These belts and zones move in either an easterly or westerly direction, driven by powerful winds. Within and between them there are many weather systems: anti-cyclones that roll along like gigantic ball bearings and cyclones that are soon torn to shreds by the actions of shearing winds. An animation showed the belts and the many weather systems moving in both directions, and there was so much going on that it was impossible to see everything in only one viewing. Pauline said that every time she watches the animation she sees something new happening and I can believe it.
It is thought that heat from Jupiter’s interior is what causes these weather systems and storms. Jupiter emits nearly twice as much heat as it receives from the Sun, so it is generating heat, which will be passing up through the atmosphere. The belts and zones are all fixed at their own separate latitudes. Near the poles this structure breaks down, and is replaced by a complex cloud structure that makes the polar regions look suspiciously like a brain!
On the subject of clouds, Jupiter has the greatest variety (and quantity) of cloud structures in the solar system (beating even the Scottish Highlands in observing season) with swirls, whirls, festoons, waves, cyclones and anti-cyclones all being demonstrated. Associated with the cyclones are incredible thunderstorms with hailstones the size of cars and powerful lightning storms.
The atmosphere seems to be broken down into three main layers. The top layer is made mostly of ammonia ice clouds, in the middle is a layer of ammonium hydrosulphide clouds, and the lowest layer is thought to contain clouds of water ice. All should produce ice crystals that are white in colour so Astronomers are unable to fully explain the colourful clouds found within Jupiter’s atmosphere.
Pauline talked about some of the probes that have visited and imaged Jupiter, including Pioneers 10 and 11, Voyagers 1 and 2, Ulysses, Galileo, Cassini-Huygens and New Horizons. As well as those close-quarter visitors, Jupiter has been extensively imaged by the Hubble Space Telescope. The Galileo probe was of particular interest as it was the only one that actually penetrated into the gas giant’s atmosphere. The probe entered the Jovian atmosphere on September 21st, 2003, at the incredible speed of 170,000kph (making it the fastest man-made object ever). To slow the descent, Galileo had a heat-shield that was mostly destroyed upon entry. Then a pair of parachutes deployed one after the other to further slow the probe. This left the wheelbarrow-sized instrument drifting down between the clouds at only a couple of hundred kph.
It was supposed to descend through the three distinct cloud layers, including the inferred water ice clouds, but this last layer was absent and the other two barely detectable. Some Ammonia ice clouds might have been found, and possibly a layer of Ammonium Hydrosulphide, but definitely no water ice. This was a disappointment, but it was thought that the probe may have dropped through what astronomers call a ‘hot spot’. Not technically hot, just a little less freezing than the surrounding area, these hot spots represent areas where there is a downdraft in which air is forced downwards through a gap in the clouds. Could this be another mechanism of Jupiter’s complex weather? Regardless, it meant that nothing could condense in that area, so it would be impossible for water ice to appear. As a matter of interest, the size of the hot spot was about that of Australia!
The interior is under so much pressure that the molecular Hydrogen and Helium in the atmosphere (which is equivalent in scale to the thickness of the skin on an apple) gradually turns into liquid Hydrogen and Helium. Eventually, at a million times the pressure at sea level on Earth, the liquid slowly transforms into metallic Hydrogen. Since the electrons have been squeezed out of the Hydrogen atoms, this layer becomes an excellent conductor of electricity and it is from here that Jupiter’s magnetic field is thought to be generated. At the very centre of Jupiter pressures have reached an incredible 70 million times the pressure at sea level on Earth and temperatures have risen to a scorching 17,000 degrees C and possibly higher – hotter than the surface of the Sun.
Pauline also discussed Jupiter’s incredible magnetic field, with its billion-km long magnetotail stretching out into space away from the Sun. This is another of Jupiter’s claims to fame: its magnetosphere is the largest structure in the solar system. Jupiter’s magnetic field is very large and very powerful. It is linked with the moon Io, and when electrons travel along that link (a magnetic flux tube) and collide with atoms in Jupiter’s atmosphere, remarkable aurorae occur. When they collide with atoms in Io’s thin atmosphere, they also create lightshows of red, green and blue emissions. Again, Jupiter claims another ‘biggest’ here: the aurorae produced in its atmosphere are up to 1000 times more powerful than the Earth’s!
Unlike Saturn, Jupiter does not have an easily-seen ring system. It does have rings, but they are much less dense than Saturn’s. The particles they are made from are very fine – about the same as pollen or cigarette smoke. The rings were only discovered in 1979 by the Voyager 1 probe. Given the low density of the rings, they shouldn’t last more than a thousand years or so. Therefore if they are still around the material must be replenished from somewhere. It is now believed that the dust produced when Jupiter’s four small innermost moons (Adrastra, Metis, Amalthea and Thebe) are struck by debris replenishes the ring system.
These are not Jupiter’s only moons of course. As well as the Galilean moons (Io, Europa, Ganymede and Callisto) and the four mentioned already there are another fifty-five! Most of the smallest satellites were discovered after an intense search by ground-based telescopes and sensitive CCD cameras.
There was more to hear and see, and Pauline discussed it all with the assurance of someone who has thoroughly researched their subject. The pictures were amazing, and it is fantastic to realise that they are available for anyone to see and download from the many planetary science websites on the Internet, including Nasa, JPL, and many others. Pauline closed by promising to give us another talk, this time on Jupiter’s Galilean moons, maybe next year.
Our HAS field trip to Jupiter was very enjoyable and rewarding. We look forward very much to the next such outing with our tour-guide, Pauline.
Highland Skies – February 2008
February brings a welcome return to our skies from an old favourite: Saturn. Trailing Regulus in the constellation of Leo in the southeastern sky, Saturn will be at about 35 degrees altitude by 9pm mid-February and will reach opposition on the 24th. It should be possible to see the shallow 8-degree angle that the ring system is now at. Whereas a couple of years ago it might have been very easy to make out the Cassini Division within the rings, now it will be much more of a challenge. It is still possible to discern detail in the rings though, as I discovered on one night of good seeing in January.
With the ‘distraction’ of the rings somewhat reduced, it may now be possible to pick up detail on the disc of the planet that might before have gone unnoticed during quick looks. Saturn’s rings will be almost completely ‘closed’ to us in early 2009, and will start to open up again thereafter. The disc can display some very subtle detail, including belts and zones of differing colours. Saturn also has a history of spots, similar to Jupiter’s Great Red Spot, except they tend to be white. Most telescopes even down to 60mm aperture will show Titan, Saturn’s largest moon, and larger telescopes (5” and up) will show several of the others, including Tethys, Rhea, Dione and Iapetus, all of which are of 10th or 11th magnitude. Hyperion will require a larger telescope as it is only 14th magnitude, but will be an ideal project for the new 14” telescope at the observatory.
In the meantime, the southern sky contains many interesting and beautiful objects to look out for, as mentioned in this month’s Seeing Stars article published on 1st Feb in the Inverness Courier. M44, the open cluster known as “Praesepe” or “Beehive” is now high and easy to spot as a faint hazy glow with the unaided eye. Binoculars or a low-power wide-field telescope will show it as a large spattering of stars spread over an area only slightly smaller than M45, the Pleiades.
Further open clusters can be explored in the constellations of Gemini and Auriga. Auriga is almost at zenith and Gemini high in the south. M35 lies just north of the foot of Castor, the uppermost twin in Gemini. Very close to it (visually) is a smaller fainter NGC cluster: 2158. From there you can follow a chain of clusters Northwest through the sky – M37, M36 and M38 being the most noticeable ones in Auriga. Anyone got a large Dobsonian? If so, NGC1931, just next to M36 could be a challenge. It is quite faint at only 11th magnitude but has some nebulosity associated with it, so could be a good target for large telescopes looking for new targets. NGC 1907, just south of M38, would be an easier one to spot. It’s quite noticeable at magnitude 8, well within reach of good 3” refractors.
For those dedicated Moon-watchers among you, Luna will be at Perigee (the closest point to Earth) on the 14th, so features may appear slightly larger and clearer than otherwise if you have been observing them regularly over a long period of time. Its distance will be 370,219Km (230,043 miles) – well within range of a good diesel engine!
Enjoy the February skies!
This month’s Stellarium presentation by Eric Walker concentrated on the area of sky covered by Rhona in her recent ‘Seeing Stars’ article. The constellations of Canis Minor and Cancer were explored, with visual representations of the various open clusters contained therein shown on the projection screen. Eric also pointed out the Winter Triangle asterism, comprising the stars Betelgeuse, Procyon and Sirius. The Auriga clusters were looked at in depth, and some of the lesser known and harder-to-spot ones that appear quite close by, like NGC 1907 and NGC 1931. Eric has taken it as a personal challenge to image NGC 1931 and show the red nebulosity that floods the area! He also showed the viewers where to look to spot Saturn now that it is easily visible again, and zoomed in to show what the planet’s ring structure would look like now that they are nearly edge-on to us.
Stellarium is an excellent utility and is proving very useful at the meetings to guide members around the night sky. You can download it for home use from their website, and they have a very useful Forum page to help you with any problems you may have. Alternatively, you can drop Eric or myself a line.
The next meeting will take place at the NTS Culloden Visitor Centre , 7.30pm on Tuesday 4th March. Neil Bone will be there, talking about meteors, and we will be assessing the facilities offered at the centre, as it could possibly be used by the Society as a meeting venue instead of the Green House in the future. The other usual features of HAS meetings (chatter, information, updates, tea + biscuits, raffles) will all take place too.
For the latest updates, please refer to the Society website and feel free to register and leave a message on the message board if you have a question, observing report or comment to make.
See you at Culloden on 4th March!