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Star chart correct for 1st Oct (23h UT), 16th Oct(22h UT), 31th Oct (21h UT). le Moon position correct for 23h UT on day indicated by number nearby. Planets correct for the beginning of the month mp 7 6 5 ●♃ 4 31 3 30 2 29 1 28 27 26 25 Sa 24 23 22 21 20 © 2012 Scarborough & Ryedale Astronomical Society, All Rights Reserved Not to be reproduced in any format without prior written consent from SARAS Welcome to the October edition of skynotes. I started work on this edition the weekend following Starfest, sat at Cadwell Park British Superbike meeting. There was a thunderstorm overhead producing hailstones the size of marbles! and constant thunder and lightning. I’m so glad I didn’t take my solarscope! I have decided to send out PDF Skynotes to everyone on email. If you don’t want to le receive it in PDF let me know. Some of you have already done this. I still need to know if you wish to receive it in its paper format. This months edition is a bumper one. There are plenty of images to drool over from Starfest as well as the usual articles. I have also made it so you can click on an article in the contents list and it should take you straight to that page. There are also links to the people who are coming to give us talks. Click on their name and it will take you to a website with information about them. Mell Jeffery, F.R.A.S. mp Treasurer and Editor, SARAS. October Star Chart Front Cover Welcome 2 Astronomical Events - October 2012 3 Moon 3 Mercury, Venus & Mars 3 Moon Chart 4 Jupiter, Saturn, Uranus & Neptune 5 Other Events 5 Constellations 5 Sa Sun Starfest Report 6 Starfest Thank You’s 8 Starfest Images 9 Member Section Bob Christy 13 Planetary Volcanism - Andy Exton 14 Aries - Mell Jeffery 21 Newsletter 24 2 le During all of the month except the very last day, the Sun is passing through the constellation of Virgo. This constellation is the second largest, area-wise, in the entire sky – the largest being Hydra (the swamp snake). On October 31 st around 00h00, it passes into Libra. The Moon mp The Moon is at apogee, its furthest from the earth, on the 5th at 00h44, and at perigee its nearest to the earth at 01h03 on the 17 th. Last Quarter Moon is on the 8th at 07h34 high in the constellation of Gemini, to the upper left of Orion and is one of the highest Last Quarter moons of the year. October’s New Moon takes place on the 15th at 12h03 in Virgo, near its brightest star Spica. The moon passes 3° south of the sun at this time. The First Quarter Moon occurs on the 22nd at 03h33 in eastern Sagittarius. The Full Moon at 18h50 on the 29th is often called the Hunter’s Moon, named after Herne the Hunter, who leads the Yell Hounds across the early winter sky, and whose ‘yelping’ can be heard in the skeins of wild geese migrating at this time. Alternative ideas have been put forward for the name given to this Full Moon; one idea is that as the moon is now higher in the sky when full, it gives more light for poachers to stalk their prey. Another is that when the moon is high in the south at midnight, the constellation of Orion the Hunter is completely clear of the SE horizon for the first time since last winter. Look for the Hunter’s Moon this year in the constellation of Aries, 9° below the constellation’s brightest star Hamal. You may observe the morning cone of the zodiacal light during the second half of the month. Look for its ethereal glow in the morning sky from 15th to the 27th The Planets Although Mercury is an evening object reaching its greatest angular elongation of 24° east of the sun on the 27th, its low position near the SW horizon prevents it from being seen. Indeed, at the time of greatest elongation it sets just 25 mins after the sun. Sa Throughout October Venus continues to shine splendidly as the morning star, rising around 4 hours before the sun. It is the brightest star-like object in the night sky and casts a perceptible shadow on a sheet of white paper if you hold your finger up between Venus and the paper in a dark corner of the garden away from external lights. At the start of twilight around 04h30 on the 12 th, Venus will be seen at an altitude of 15° in the east below the figure of Leo, with the thin waning crescent moon 10° below the planet, near the horizon. Mars continues to fade during October and is always low in the SW sky, almost lost in evening twilight. On the 6th, it leaves the constellation of Libra and enters Scorpius, and on the 18th the planet enters Ophiuchus and is a little dimmer than most of the true bright stars in the sky. Mid month, Mars is two astronomical units from earth (1 a.u. is the mean sun-earth distance). At the end of October Mars climbs a little higher in the sky and sets almost two hours after the sun, and is marginally easier to see. There is an opportunity to spot the thin waxing crescent 3 Sa 4 le mp moon and Mars within 5° of the SW horizon on the 18 th at 18h. At that time, Mars lies 2° to the lower right of the crescent. le Jupiter (♃ symbol on the Star Chart) rises by 20h at the beginning of October and by 18h at the end of the month, and is now shining steadily and serenely all night long between the horns of Taurus the Bull. Before Venus rises, Jupiter is by far the brightest object in the night sky. On the evening of the 5 th, the gibbous waning moon may be seen rising 2° below Jupiter in the NE, when a pretty conjunction may be witnessed around 21h. Look for the Galilean satellites in the usual well focussed and firmly fixed binoculars. Saturn is lost in evening twilight and on the 26 th lies in conjunction with, and far beyond, the sun, to reappear next month as a morning object. mp Neptune is crossing the south meridian, ie is due south in the sky, at around 21h during October. It is difficult to locate unless you have star maps as it is over five times fainter than the faintest star visible to the naked eye, so is not excessively bright in binoculars. This is not so with Uranus, which on the darkest nights is just visible to the unaided eye. Once again though, it is necessary to know where the planet is, in order to see it. Neptune is currently in Aquarius, and Uranus in western Pisces. Other Events Sa Some more remnants of Halley’s comet may be seen in the early hours of the 21 st, when the earth encounters the Orionid meteor stream. Up to 25 shooting stars an hour are expected. These meteors are fast moving and often leave persistent trains. This year’s event should be favourable, as the moon, a broad waxing crescent, will have set earlier in the evening. The biggest number of Orionids will be visible just before dawn, when the constellation of Orion is high in the south. The radiant, or point of origin of the shooting stars is some 10° above Betelgeuse, the star which marks the right shoulder of the Giant Hunter. Earlier in the month on the morning of the 8th, a slight increase in the number of shooting stars overnight marks the peak of the Draconid or Giacobinid (whose parent body is the comet Giacobini-Zinner) meteor shower, with its radiant in the constellation of Draco the Dragon. Last year the earth passed through some concentrated filaments of particles, producing a high rate of about 500 meteors an hour. It is not likely, although not impossible, that there is a repeat this year. The moon is at last quarter later on in the day, and so may interfere with the number od Draconids seen. The meteors have the reputation of being slow moving but faint. Constellations Constellations visible in the south around midnight, mid-month, are as follows: Cetus, Pisces, Aries, Triangulum and Andromeda. Cassiopeia and the Milky Way lie at the zenith, with the Milky Way spanning the sky from east to west. All times are GMT 1° is one finger width at arm’s length. John Harper , F.R.A.S. 5 le “...the Dalby forest night appears as good as "Kielder" and definitely darker than the Kelling Heath sky in Norfolk…” - Mick Phipps. Before I tell you about the Starfest weekend, I would like to thank all those members who came to help. As we had quite a few people come forward to help it meant that jobs could be allocated, rather than a few of us doing everything and then not getting the chance to enjoy the weekend. On the Wednesday a group of members went up to Adderstone field to set up the pitches and rope off the site, the toilets where also delivered. mp This all took place before several of us arrived on site to set up camp! Jim and Sheila Cornmell and Sue and Dave Greenwood had already pitched their tents before the rain and ourselves arrived! Poor Andrew got a soaking while pegging down the caravan awning! Mind you that was nothing compared to the rain that came about 30 minutes later! BUT when that weather front had cleared through, it left us with a beautifully clear night! We got our 12” Revelation Dobsonian out and observed the following objects: M22, M57, M31, M32, M110, M91, M81, M82, NGC404, Albireo, parts of the Veil Nebula, M13 + Nearby Galaxy and M15. There was probably a few more objects, but I couldn’t remember them all! Sa Thursday started out as a beautiful day. I had a meeting with Richard Darn to take some pictures to help promote astronomy and in particular the Bat and Stars night on the 25th August. I was lucky as I took Alicia with me and so they decided that she was far cuter than me and so she got roped in for the photo session instead, much to her teenage disapproval. The shots where taken at Haygate, just as you come into the forest. The pictures were then used to accompany articles in the Yorkshire Post, Evening Press, Gazette and Herald and the Mercury, these are the ones we are aware of, plus some online articles. I got my solarscope out in the afternoon and had some brilliant views of sunspots, filaments and several large prominences. It also saw the arrival of the people who were booked in to arrive that day. It was nice to see people who I hadn’t seen for almost a year. Unfortunately the cloud came in that evening and we were unable to do any observing, socialising was the order of the day, or rather evening! Friday didn’t start out very well, it was raining on and off, but that started to dry up come the afternoon. The majority of people had by now arrived. The hogroast arrived and everyone enjoyed it, some going back several times for seconds! It was also noted that it was dry during the Hogroast, unlike previous years! There was still plenty of cloud about that evening, with just the odd break here and there, but not really big enough patches to break out the telescopes. Saturday evening was similar! Several raffle tickets had been sold during Friday and 6 le Saturday and that evening we held the raffle. Prizes included wine, books a few astronomical observing items and a few other items. We were then treated to a talk by John Nichol. He spoke about David Sinden—A life in Optics. That evening saw some large patches of clear sky move over Adderstone Field, enough to get the telescopes out . John Harper helped us to find some interesting objects one of them being Alamak ( Andromedæ) this is a double star that is very similar to Albireo in Cygnus. Another interesting double that John pointed out to us was Mesarthim ( Arietis), this looked just like 2 little cats eyes peering back at you. I also managed to split Lyræ, the Double Double! The Andromeda Galaxy was visible but not as clear as on the Wednesday evening. mp Sunday saw some of our guests leave. This is normal, with Monday not being a bank holiday like it was last year. Some of the site was taken down by the helpers ready for taking down to the stores on the Monday morning. It also saw plenty of entertainment. We had the usual rocket competition in the morning. As we had fewer children participating, it was decided to let the adults have ago!! The children’s competition was won again by Hannah Jeffery (a society member) and the adult competition was won by Keith Johnson. Later that afternoon saw 2 members of Scarborough AS take on 2 members from North Devon AS at boules! There was a late substitution when one member from North Devon AS took over from one of the Scarborough AS members! The results were as follows: Mell Jeffery 8, Mark Buckingham 3, Andrew Jeffery / Julie Buckingham 1 and Rick Dooley 1! This also saw the arrival of sunshine and solarscopes were in use again. Later that evening saw the Quiz. Quizmasters this year were John Harper and Sheila Anderson, with Angela Taylor scoring. There was plenty of booing, cheering and thinking going on amongst the 5 teams. The winning team was, as usual, Durham (John, George and Juergen) followed by the Scarborough team ( Andy, Howard and Jim). We also had a second team consisting of Sue & Dave Greenwood and David Trigg. After the quiz, Juergen gave a talk and the skies cleared. Everyone got their scopes out and the skies delighted all those that remained. The only issue we had was the amount of dew, this was possibly due to a heavy downpour we had during the quiz. Some people retired due to the dew problem, but some of the hardened imagers were up until 5:30 Monday morning! Sa Monday saw everyone left packing up and heading home. It was a sunny day so no tents / awnings were put away wet . And the rest of the equipment was taken down to the stores. Having checked my emails in the few days after Starfest, it was nice to see plenty of people thanking us for an enjoyable weekend and some even sending us some of their images. Alicia Jeffery (Society Member) at the ‘photo shoot’ for publicising the ‘Bat and Stars’ night with the Forestry Commission. The event was the weekend after Starfest, but the images taken in Dalby on the Thursday of Starfest. Image use courtesy of Richard Darn. Mell Jeffery, F.R.A.S. 7 le First of quite a few results from last night/ this morning. I ended up staying out until around 0330, but was very satisfied with the results. If you want more details of this image or more images from the set that I got just let me know. Thanks for the hospitality. Hope to see you in 2013. mp Robert Williams Just a quick note to thank you and your helpers for another very social, friendly and (clear nights on Thurs, Fri and Sat not withstanding!!) successful Starfest. I was down in Malton on Sunday evening under clear skies till at least 2300, so though I didn’t return on Sunday afternoon I trust some clear spells were enjoyed with those that remained. I was kicking myself for packing up completely on Sunday morning Sa David Croston On behalf of the members of the Border Astronomical Society I just want to say a thank you to all those involved for an enjoyable Starfest last weekend. The weather was much better than in previous years and the helicopter display was very impressive :-) We hope to see you all again next year. Regards, David Pettitt. Sec: Border Astronomical Society. Dear Mell and all who tirelessly organize the Dalby Star Camp each year. A big thank you again for a wonderful break in the forest, though I didn't get around to meeting you this time - my apologies for that - I was very happy to be there again. After it seems several years of waiting your efforts were finally rewarded with a superb sky on Sunday after the Astro-mind. For what it's worth I can tell you that, as a deep-sky observer for nearly 30 years now, the Dalby forest night appears as good as "Kielder" and definitely darker than the Kelling Heath sky in Norfolk. Long may the August Astro Camp continue. Best Regards... Mick Phipps. 8 le All of the following images have been reproduced with kind permission of the owner. Friday Evening Sunset. Sa mp Image credit: Keith Johnson Andromeda Galaxy (M31) and associated galaxies M32 and M110 Image Credit: Keith Johnson Triangulum Galaxy (M33) Image Credit: Keith Johnson 9 le Sa mp Starfest Campsite. Images Credit: Juergen Schmoll Rocket Competition and Air Ambulance (Not for Starfest!) Images credit: Juergen Schmoll 10 The following 5 images are also credited to Juergen Schmoll mp le M45 Pleiades Sa Summer Triangle NGC 7000 North American Nebula 11 Sa mp le Veil Nebula Triangulum Galaxy M33 Solar Observing Image Credit: Mell Jeffery 12 le mp Bob Christy, who is speaking at the November meeting is a recent arrival in Scarborough. He originates from Kettering in Northamptonshire and, while at school, developed a strong interest in satellites and space history. A major driver was being a member of the Satellite Tracking Group at Kettering Grammar School which was responsible for providing much in the way of detailed information on what was then the Soviet Union's secretive space programme. He continues that interest nearly fifty years later by publishing the "Zarya" web site that specialises in current and historical space events. The site's emphasis is providing information from a different angle to straightforward news stories. There are analyses that pull in information from different directions, and added information from actually tracking satellites in orbit using radio. One of the most popular pages on the site is "Go for Launch!" which is a calendar of upcoming events. It is updated daily and provides links to more-detailed news sources, and webcasts of space events such as launches, and dockings at the ISS. For skywatchers in Yorkshire, there are some special pages giving predictions for highly-predictable flares from the Iridium telephone relay satellites. Many of you will have seen one either by deliberately seeking it out, or by chance when one of them reached magnitude -8 in the area of sky you just happened to be looking at. For current events, there is a Twitter feed, or if anyone prefers, the same information feeds through to Facebook. Sa Main site: http://www.zarya.info The items mentioned above are all in the right hand menu: Go for Launch! - http://www.zarya.info/Calendar.php The Kettering Group - http://www.zarya.info/Kettering/Kettering.php Astronomy for Yorkshire IridiumFlare.php?site=SCA (Iridium flares) - http://www.zarya.info/AstroYorks/ Twitter and Facebook links are on the menu bar at the top of the page: Twitter - https://twitter.com/Zarya_Info# Facebook - http://www.facebook.com/pages/zaryainfo/150898915007077 13 le mp This month, I have decided to produce a 2 part planetary science article on volcanism which will continue next month. What powers volcanism on Earth, where does it occur and is all volcanism the same on Earth? Next month, I will look elsewhere in the Solar System to explain evidence of past and present volcanism. Unlike the Moon and other planets and satellites in the Solar System, the Earth shows little in the way of impacts from asteroids and comets. Considering that the Moon and Earth have shared the same region of space for around 4600 million years, it should be expected that the Earth has had the same number of collisions per unit area as the Moon. Two reasons exist for Earth’s uniqueness. Firstly, there is the existence of plate tectonics and active volcanoes. Secondly we have an atmosphere, water and living organisms that weather and erode the rocks and minerals at the Earths’ surface. Due to these processes, Earth is termed a ‘Dynamic Planet’ (Webb et al, 2010). The movement of tectonic plates and the production of magmas require heat. But what is the source of this heat currently and throughout the history of the Earth? Well in fact, there are 6 sources (Rymer and Drury, 2009), namely: Heat of accretion: In planetary terms, the process of accretion is the growth of a planet as a result of bombardment by fragments of rock and planetesimals (small bodies several kilometres in diameter) (Allaby, 2008). The gravitational potential energy of these rocky bodies accelerating towards Earth was converted to kinetic energy and upon collision, this energy was converted, much of it being to heat (Rymer and Drury, 2009). Sa Heat of compression: As a planetary body like the Earth grows in size during its formation, the material towards the centre of the body becomes compressed with material being accreted on the outside. The rocks undergoing compression as a result become heated, with heat increasing significantly with depth due to the poor heat conductivity of rocks (Rymer and Drury, 2009). Core formation: The Earth has differentiated into a number of layers due to the density of the materials forming them (Figure 1). Earth has a dense core, this being surrounded by a less dense mantle, topped by an even lesser density crust. The dense rocks that formed the core migrated there from shallower depths, sinking under the influence of gravity due to higher densities compared to other Earth forming rocks. Whilst sinking, this gravitational potential energy underwent conversion to heat (Rymer and Drury, 2009). 14 le Figure 1: Structure of Earth (USGS, 1999) mp Before moving onto the next two heat sources I will firstly explain the term isotope. An isotope is an atom with the same number of protons but a different number of neutrons in its nucleus compared to another atom. For example, hydrogen exists as three different isotopes in nature; hydrogen (1 proton, no neutrons), deuterium (1 proton, 1 neutron) and tritium (1 proton, 2 neutrons) (Daintith, 2008). Radioactive isotopes are those that are unstable and hence undergo radioactive decay from a parent nuclide into a daughter nuclide and releasing other nuclides or particles (Figure 2) with a half-life being defined as the time taken for half of the original nuclides to decay (Daintith, 2005). Short-lived radioactive isotopes: By short-lived radioactive isotopes, it is those with half-lives less than 1 million years which compared to the age of the Earth is a considerably short time. Early accreted materials into the Earths’ structure which will have been formed from supernovae explosions will have decayed in the first few million years, releasing energy that will have been trapped within the Earth (Rymer and Drury, 2009). Long-lived radioactive isotopes: Radioactive isotopes are those with half-lives longer than 1 million years. In the early history of the Earth, these contributed little in the way of heating but are still important today. Three radioactive isotopes 238 contributing to heating today are uranium-38 ( U), thorium-232 (232Th) and potassium-40 (40K) (Rymer and Drury, 2009). Sa Figure 2: Radioactive decay of Uranium-238, producing an atom of Thorium-234 and a Helium-4 atom (Bodner). Tidal Dissipation: The gravitational pull due to the motions of the Sun and Moon result in the Earth being deformed, as well as the oceans and atmosphere (Figure 3). 15 mp le The deformation results in the Earth’s interior being heated due to friction (Allaby, 2008) and earlier in the history of the Earth, this effect will have been significantly greater due to the orbit of the Moon being closer to the Earth (Rymer and Drury, 2009). Figure 3: The effects of the Sun and Moon on the oceans. Note the Earth is also stretched in this way although not shown in the image (HowStuffWorks) Plate tectonic movements are very slow indeed with movements of only a few cm per year being typical. In total there are around ten major plates that give the Earth a broken egg shell appearance. From Figure 4, it is clear to see that the majority of volcanoes on Earth (red dots) are situated close to the plate boundaries, with those surrounding the Pacific Ocean being termed the “Ring of Fire”. Three different types of tectonic plate boundaries occur; divergent (constructive), convergent (subductive) and transform (Blake et al, 2010). Sa Before moving on, I will firstly introduce two terms lithosphere and asthenosphere (you may have noticed these two words on Figure 1). Tectonic plates are formed from slabs of lithosphere (‘lithos’ being the Greek word for rock). Lithosphere is the crust and the upper most part of the mantle (around 100km) and they move together over the asthenosphere (‘astheneo’ being the Greek word for weak), a weaker, partially molten layer that allows the lithosphere to flow over it. Lithosphere can come in the form of continental or oceanic lithosphere. Oceanic lithosphere is basaltic in composition and is generally 6-11km thick, forming the ocean floors. Continental lithosphere forms the continents; can be as thick as 90km and geologically is composed of igneous rocks rich in silica; sedimentary rocks formed through erosive and biological processes; and metamorphic (recrystallisation of igneous and sedimentary rocks as a result of heat / pressure reactions). Convection in the mantle allows heat to be transported upwards to the base of the lithosphere, being replaced by cooler, denser mantle, ultimately providing the heat source to aid tectonic movements (Rothery, 2007). Figure 4: Map of the Earth showing the tectonic plate configuration and the location of major volcanoes (USGS, 1997) 16 le mp Figure 5: Simple diagram showing plate divergence (USGS, 2004b) Sa Divergent plate boundaries (Figure 5) are responsible for the creation of new lithosphere. The most common location for divergent plate boundaries are in the form of mid-ocean ridges as a result of a process known as sea-floor spreading, such as that found in the North Atlantic known as the Mid-Atlantic Ridge (Figure 4). Another area home to a constructive plate margin is the Red Sea, which is a young sea currently opening. Interestingly, the East African Rift Valley in Ethiopia may well follow suit in the future (Rymer and Drury, 2009). A divergent plate boundary is believed to be formed when convective currents in the asthenosphere having moved upwards diverge at the top of the asthenosphere, causing a drag on the lithosphere above causing it to rupture. This rupture then continues to move apart forming a divergent plate boundary. Molton rock fills the void and is quickly cooled as a result of seawater, producing new oceanic lithosphere (USGS, 2004b). The continued upwelling of molton rock produces mid ocean-ridges, which consist of underwater volcanoes and the continued slow movement of the tectonic plates continues the formation of these ridges (Rothery, 2007). Convergent plate boundaries can take the form of collisions between oceanic and oceanic (Figure 6), continental and oceanic (Figure 7) or continental and continental plates (Figure 8) (USGS, 2004). Figure 6: Simple diagram showing continental vs. oceanic plate convergence (USGS, 2004a) Oceanic plates are denser than continental plates so a collision between plates of each type results in the denser oceanic plate being forced downwards underneath the continental plate. The downward motion of the oceanic 17 le plate pulls the rest of the plate with it, entering the asthenosphere, forming a subduction zone. At the point where the two plates meet, an ocean trench is formed (Figure 6). As the subducting plate moves deeper into the asthenosphere, melting occurs due to temperature and pressure changes, as well as the effects of water. This heated molton rock rises upwards as magma, producing volcanic arcs on the continental crust. Magma may solidify below the surface forming magma chambers or it may form volcanic eruptions that over time form volcanic mountain ranges (USGS, 2004). Examples of these processes currently occurring include the West coast of South America and the North West coast of North America (Rothery, 2007). Figure 7: Simple diagram showing oceanic vs. oceanic plate convergence (USGS, 2004a) mp Whereas a collision between oceanic and continental lithosphere results in the subduction of the denser oceanic lithosphere; a collision between two slabs of oceanic lithosphere relies on the denser slab being subducted (Figure 7). Oceanic crust is formed at divergent plate boundaries, and over time the lithosphere cools and becomes denser; so the colder and older of the two plates is subducted. The formation of an ocean trench and the melting of rocks occur as with the oceanic / continental scenario but the eruption of magma at the surface does not occur on land. In this scenario, the eruption occurs initially on the ocean floor but over time, the peaks of the volcanic mountains break through the ocean surface and an island arc is produced. An example of this scenario is the Aleutian Islands off the coast of Alaska (USGS, 2004a). Figure 8: Simple diagram showing continental vs. continental plate convergence (USGS, 2004) Sa Convergent plate boundaries can also collide with each other. As mentioned previously, continental lithosphere is buoyant so when they collide, neither can be subducted (USGS, 2004a). As a result, the plates become buckled and drive upwards against each other forming large mountain ranges (Figure 8), eventually fusing the plates together. As no subduction zone exists, there is no source for magma to rise upwards so mountain ranges created by this method are not generally associated with volcanism. Examples of mountain ranges formed in this way are The Alps and The Himalayas (Rothery, 2007). Figure 9: Configuration of plates creating the San Andreas Fault (USGS, 2004c) In contrast, transform plate boundaries are neither responsible for creating or destroying lithosphere. The plates along a transform boundary slide along each other, grinding as they make contact with each other. No magma generation is 18 associated with them but some of the world’s major earthquake zones lie along them. Possibly the most famous example of such action is the San Andreas fault running through California (Figure 9) resulting from the opposite movements of the Pacific and North American plates (USGS, 2004c). le However, some volcanoes appear in the centre of plates and are known as hot spots or intraplate volcanoes, resulting from magmas erupting from below melting the lithosphere above. Whilst the tectonic plate has the ability to move, the magma store remains fixed. Over a period of time, the continued eruption of magma in one spot forms an island chain, as the plate above continually moves away from the hotspot (Blake et al, 2010). A famous example of a hot spot is the creation of the Hawaiian Islands chain (Figure 10). Sa mp Figure 10: Formation of an island chain by a fixed hot spot (USGS, 1999b) To conclude, it is clear to see that the Earth is an active body with numerous constructive and destructive processes occurring, which over many millions of years have reshaped the continents and moved them to their current configuration (Figure 11). It is these tectonic processes along with other geological processes including erosion and deposition that have resurfaced the continents. This is believed to be the reason that historical meteorite and comet impacts that have cratered other planetary bodies have been obscured here on Earth. Figure 11: Continental movement throughout the past 225 million years (USGS, 2012) 19 References: Allaby, M. (2008) Oxford Dictionary of Earth Sciences (3rd Edition), Oxford University Press, Oxford le Blake, S., Argles, T., Harris, N. (2010) Magmas and Mountains, S276 Geology(Book 2), Open University Press, Milton Keynes Bodner (2012) Radioactive Decay, Bodner Research Web http://chemed.chem.purdue.edu/ genchem/topicreview/bp/ch23/modes.php [Accessed 7 September 2012] Daintith, J. (2005) Oxford Dictionary of Physics (5th Edition), Oxford University Press, Oxford Daintith, J. (2008) Oxford Dictionary of Chemistry (6th Edition), Oxford University Press, Oxford mp HowStuffWorks (2008) How Ocean Currents Work, How Stuff Works http:// science.howstuffworks.com/environmental/earth/oceanography/ocean-current4.htm [Accessed 7 September] Rothery, D. A. (2007) Teach Yourself Volcanoes, Earthquakes and Tsunamis (2nd Edition), Hodder Education, London Rymer, H., Drury, S. (2009) Earth’s Engine (4th Edition), S339 Understanding the Continents (Book 1), Open University Press, Milton Keynes USGS (1997) Active Volcanoes, Plate Tectonics, Hot Spots and the Ring of Fire, United States Geological Society http://vulcan.wr.usgs.gov/Glossary/PlateTectonics/Maps/ map_plate_tectonics_world.html [Accessed 7 September 2012] USGS (1999a) Inside the Earth, United States Geological Society http://pubs.usgs.gov/gip/ dynamic/inside.html [Accessed 6 September 2012] USGS (1999b) “Hotspots” Mantle thermal plumes, United States Geological Society http:// pubs.usgs.gov/gip/dynamic/hotspots.html [Accessed 7 September 2012] USGS (2004a) Convergent Plate Boundaries, United States Geological Society http:// geomaps.wr.usgs.gov/parks/pltec/converge.html [Accessed 10 September 2012] Sa USGS (2004b) Divergent Plate Boundaries, United States Geological Society http:// geomaps.wr.usgs.gov/parks/pltec/diverge.html [Accessed 13 September 2012] USGS (2004c) The action is at the edges, United States Geological Society http:// geomaps.wr.usgs.gov/parks/pltec/pltec3.html [Accessed 13 September 2012] USGS (2012) Historical Perspective, United States Geological Society http://pubs.usgs.gov/ gip/dynamic/historical.html [Accessed 13 September 2012] Webb, P., Argles, T., Sheldon, P. (2010) Minerals, Rocks and Maps, S276 Geology(Book 1), Open University Press, Milton Keynes 20 le The ram has played various roles in mythology and in religion. For example, the Egyptian God of Fertility and Creative Life was depicted as a creature with the body of a man and the head of a ram. mp One mythological story is that of King Athamas of Boetia (Asia Minor). His Queen was a Goddess, Nephele. Although it was common for mortals to marry Gods/ Goddesses, they weren’t allowed to stay on Earth indefinitely. When she had to leave she left her son, Phrixos and her daughter, Helle in the care of the King. Soon after he remarried. The children’s Step Mum, Ino, eventually turned against the children and tried to get rid of them. She spread disease in the crops, which caused the harvest to fail and then spread rumours that the Gods were angry with the 2 children. Ino corrupted the Priests, who advised the King that his children should be sacrificed. Nephele saw what was happening and during the night came down from Olympus and planned a rescue. When the time came for the children’s execution and they were led to the alter, a golden ram descended. They climbed aboard its back and were told not to look down as it leapt into the air. Helle could not resist the temptation to look down and as she did she fell off the ram and into the sea. Phrixos, however, arrived safely and the ram was sacrificed to Jupiter, although some say it was Zeus. He gave its golden fleece to King Aeëtis and its body was placed amongst the stars. There is another story of a ram involving Odysseus and this is were the astronomical meaning for the myth can be seen. Odysseus was brought, by a ram, from a dark cave into the light and this symbolises when the Sun is in Aries, the long dark winter Months are over and the sun shines for longer spreading its warmth. Sa From 1730BC to 420AD, Aries was the constellation of the first day of Spring, but due to the procession(1) of the equinoxes(2) this is now Pisces. Come 24,100AD the Vernal equinox will again be in Aries. Aries is situated below the constellation of Triangulum, between Taurus and Pisces. At first glance it seems an inconspicuous area of sky, with only 4 stars above 4.0 magnitude and no Messier or Caldwell objects! But on research, there is more to be seen. Arietis, Hamal, is twice the size of our Sun and is reddish. Mesarthim, Notes: 1 - Procession - The apparent movement of the celestial poles due to the Earths ‘wobble’. 2 - Equinox - When the Sun crosses the celestial equator. 21 R le Object mp Name Type Magnitude Hamal Star 2.01 Sheratan Star (spectroscopic binary) 2.64 Mesarthim Double Star Both 4.8 (Sep 7.8”) Botein Star 4.35 Double Star 5.2, 5.5 (Sep 1.5”) Double Star 4.8, 6.7 (Sep 36.7”) Double Star 5.2, 8.7 (Sep 1.5”) Star 3.61 R Ari Variable 7.4 - 13.7 NGC 673 Galaxy 13.2 NGC 678 Galaxy 13.3 NGC 680 Galaxy 12.9 NGC 691 Galaxy 12.3 NGC 770 Galaxy 14 Galaxy 10.3 NGC 821 Galaxy 11.8 NGC 877 Galaxy 12.6 Ari Ari Ari Ari Ari Sa Ari Ari 41 Ari NGC 772 Bharani Fiddlehead Galaxy 22 Arietis, is a binary star and sometimes referred to as the ’Ram’s Eyes’. Both components are white with a separation of 7.8 arcseconds. It was discovered by Robert Hooke in 1664. The star with the designation 41 Arietis was not given a Greek letter as it was originally part of a constellation called ‘Musca Borealis’ or the Northern Fly! le There are quite a few NGC objects, but they are very dim. Probably the easiest one to try to find would be NGC 772, the Fiddlehead Galaxy. This object is also listed as ‘hidden treasure no: 8’ in Stephen O'Meara's Deep Sky Companions book - Hidden Treasures. It is a spiral galaxy with NGC 770 lying close by and possibly a companion galaxy. I have listed a few other NGC objects, but all are very faint. Incidentally, the gravitational pull from NGC 678 appears to be distorting its elliptical neighbour, NGC 680! mp R Arietis is a Mira type variable with a period of 186.8 Days. There is also U Arietis which is also a Mira type with a period of 371.1 Days. Another notable variable star is T Arietis, this is a semi regular variable. There are several faint meteor showers associated with Aries. Sa Mell Jeffery, F.R.A.S. Aries, The Ram and Musca Borealis, the Northern Fly (the constellation is no obsolete) as depicted in Urania's Mirror, a set of constellation cards published in London c.1825 References: O’Meara, Stephen. (2007) Deep Sky Companions - Hidden Treasures, Cambridge University Press. Hass, Sissy. (2006) Double Stars for Small Telescopes, Sky Publishing, Cambridge, Massachusetts. Ridpath, I. (2004) Norton’s Star Atlas (20th edition), Pi Press, New York. Tirion, W. (2005) The Cambridge Star Atlas (3rd edition), Cambridge University Press. Moore, P & Rees, R. (2011) Patrick Moore’s Databook of Astronomy, Cambridge University Press. Staal, Julius. D. W. (1988) The New Patterns in the Sky, Myths and Legends of the Stars, The MacDonald & Woodward Publishing Company. http://en.wikipedia.org/wiki/Aries_(constellation) [Accessed 13 September 2012] Starry Night Pro Software Version 6.4.3 23 Scarborough & Ryedale Astronomical Society le Founded: 1976 Registered Charity No: 1092385 Honorary President: Mr John Harper, F.R.A.S. Website: www.scarborough-ryedale-as.org.uk Newsletter, 17th September 2012. mp Welcome to the first edition of Skynotes of our new season. I would like to start by welcoming some new members: Derek & Louise Brazil & Family Gary Welford I would also like to thank all those who were able to help with Starfest, especially those who were able to set up the field on the Wednesday. Starfest was a great success as ever and we had some clear skies too. Our first Public Viewing Night will be upon us soon, Friday October 5th at Dalby. If you are able to come along and help, please do so, the more the merrier. Andy Exton has done a great job sorting speakers for the coming meetings, as you will see he has about filled every available slot! If you are receiving the PDF version you will be able to click on the speakers name and it will open up a page on the internet relevant to that person. Sa We are in the process of sorting out a venue for the Christmas meal. All information should be available next month. It will be in Skynotes, but also emailed out. Up Coming Events: October 5th Public Viewing Night at Dalby. October 19th Open Evening. (Originally publicised as beginners night) October 20th Joint event with Humble Bee Farm. November 2nd Public Viewing Night at Dalby. November 16th Society Member Bob Christy, with a talk titled ‘Satellite Tracking Half a Century!’ December 7th Public Viewing Night at Dalby. December TBC Christmas Meal. 24 Public Viewing Night at Dalby. January 18th Change of Venue: Sawdon Village Hall. Members / Social Night. Change of venue due to darker skies. February 1st Public Viewing Night at Dalby. February 15th Paul Money with a talk on the Messier Marathon. March 1st Public Viewing Night at Dalby March 15th Dr Pete Edwards (Durham University) - Bringing the Universe down to Earth. (A talk about some of the space related questions of CERN and the LHC) April 19th Dr Janet Humphreys (Formerly of Leeds University and OU S282 (Astronomy) Tutor) - Cosmic Recycling (A talk on the formation of elements, stars and planets etc) May 17th Dr Simon F. Green (Open University) - Missions to Asteroids: Exploring our origins and Saving the World! (A talk on why we are interested in Asteroids, previous and future missions to them) July 19th mp June 21st le January 4th 2013 August 9th - 12th Dr Lee Sproats (Green Witch Telescopes) - Telescopes of the Future (A talk on some of the planned telescopes and where telescope design may head in the future) TBC Starfest The following has been sent out in an email, but just in case you didn’t get it, here it is. Following a chat with Joseph Gordon from Newcastle Astronomical Society over the weekend at Starfest he has sent me the following information. They have decided to hold a star party at Haltwhistle, close to Hadrian’s Wall over the 7th and 8th December. Anyone interested or would like further details, please e-mail Joseph at [email protected] . Star Party 7th and 8th December 2012 Sa Hello lads and lasses - advance notice of a star party. Organising body to be decided. Once we have more details they will be forwarded out. Standard star party format - hog roast etc. People can book up and arrive before the main event - and of course stay longer and enjoy the area of Hadrian’s Wall. Check out the link BELOW for details. https://www.facebook.com/pages/Herding-Hill-Farm-Shop-Tea-Room-Caravan-Camping-andWigwams/223840004294856?ref=ts Please let me know if you would like to attend, how many on your party and whether your camping Caravanning / motor home or using the Wigwams. Booking information and event details to follow. Thanks Joe 25 I do hope we all manage to get some decent observing sessions in this winter. Don’t forget we have plenty of knowledgeable members within the society should you be stuck and need a question answering, so don’t be afraid to ask. le We also have the society forum for posting questions, images and observing reports, amongst other things. This is accessed through the society website. We also have a Facebook page to keep you and anyone else up to date with what’s happening within the society. The web address for the Facebook page is: https://www.facebook.com/ScarboroughRyedaleAstronomicalSociety Clear Skies Andrew Jeffery mp Chairman, S&RAS. ‘That’s one small step for [a] man, one giant leap for mankind!’ Neil Alden Armstrong August 5th, 1930 - August 25th, 2012 Acknowledgements Star Chart: Starry Night Pro Version 6.4.3 Moon Phase: LunarPhase Pro Version 3.35 Sa Astronomical Events: John Harper, Sheila Anderson. Other: Mell Jeffery, Bob Christy & Andy Exton. Treasurer Mrs Mell Jeffery, F.R.A.S. 11 Chestnut Grove Norton Malton North Yorkshire YO17 9BZ 01653 691128 s&[email protected] Chairman Secretary Andrew Jeffery 11 Chestnut Grove Norton Malton North Yorkshire YO17 9BZ 01653 691128 [email protected] 26 [email protected]