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September 2007

ASTRONOTES
Incorporating FRIENDS' NEWSLETTER Exploring the Asteroids What on Earth is up with our Weather? Tycho: Wild Man of Astronomy! Calculating the odds on aliens Exploding the Asteroids

ARMAGHPLANETARIUM


2 Astronotes September 2007

Exploring the Asteroids
By Colin Johnston, Science Communicator Between Mars and Jupiter lies the Asteroid Belt. Relics of the Solar Nebula, these asteroids are the leftovers of the Solar System. Churned by giant Jupiter's gravity, they are stuff that never had the chance to become a planet. There are about a million asteroids with a diameter of 1 km or more. Only 200 or so of the asteroids in the Belt are more than 100 km across. The biggest object in the asteroid belt member is Ceres, so large it was recently up-graded from asteroid to Dwarf Planet. The three largest asteroids (Vesta, Pallas and Hygiea) plus Ceres together make almost half the total mass within the main belt. Ceres alone accounts for one-third of that total mass. Note that if Ceres and all the asteroids in the Belt combined into one lump the resulting body would be less than a twentieth the size of our Moon.

Asteroids are `living fossils' from the earliest days of the Solar System
As they are `living fossils' from the earliest days of the Solar System, asteroids are fascinating to astronomers. The largest bodies out there have, entirely through chance, survived billions of years of possible collisions and have remained intact ever since they formed. As they are the largest, Ceres and Vesta are especially interesting. Surprisingly Vesta and Ceres are chalk and cheese, or more aptly rock and ice. Observations of Vesta suggest it has a complex geology suggesting an intriguing history. Its surface features include basaltic lava flows н implying that it once had a molten core - and a deep impact crater near its southern pole. Vesta seems to be bone-dry. In a complete contrast, Ceres has a simple primordial surface with evidence of water

Three faces of Vesta? Image at top left is an actual Hubble Space Telescope image of Vesta, the groovily-coloured image is a relief map based on the first image and the top right image is a model of Vesta approximating a close-up view of the asteroid. Vesta orbits about 2.4 AU from the Sun (1 AU = 150 million km) ice. Ceres seems to possess frosty polar caps and a tenuous atmosphere. Vesta in many ways resembles the inner planets like Mars and Earth, while Ceres is more like one of the icy moons of the outer planets, such as Callisto. Clearly both worlds were created by very different processes. Think of an asteroid. You have probably imagined an irregularly shaped lump. Ceres is not like that. It is almost spherical, but not perfectly so, like the Earth its rotation means that it is slightly flattened at the poles. Recent research has suggested that this is a clue to its internal structure. If Ceres' interior was a uniform mix of ice and rock it would be flatter still, instead the more modest flattening indicates the presence of a core, presumably composed of rock, surrounded by an icy mantle. If it is made of ice, Ceres' mantle contains more water than all the oceans of Earth. Someday this may make Ceres one of the most valuable locations in the Solar System to space colonists. While Ceres is more or less spherical in shape, at half the size Vesta is potato-shaped. Hubble Space Telescope images show Vesta to be ir-

Image Credit: NASA


September 2007 Astronotes 3 regular. At widest it is about 580 km across (only slightly more than the distance from Belfast to London) but about 460 km from pole to pole. Vesta has probably enjoyed a more eventful life than Ceres. In fact Vesta has had huge fragments splintered off itself. How do we know this? Astronomers can use a technique called reflection spectroscopy to identify the presence of chemical elements on an astronomical body by the `fingerprints' they leave in the sunlight reflecting off the surface. Spectroscopic analysis indicated that several small asteroids have surfaces which are highly similar or identical to Vesta's. The best explanation is that they are indeed fragments blasted off Vesta by an ancient collision, possibly the very one which left the great crater near the asteroid's south pole. But that is not all, the visible and near-infrared reflectance spectra of Vesta and the basaltic achondrites, a class of meteorite which fall on Earth, are so similar they must be connected. Presumably these are fragments from the massive impact that have found their way to our world. We almost certainly already have samples of Vesta here on Earth! Ceres and Vesta are two fascinating worlds, worthy of further study. All being well on 26 September 2007 an explorer will leave Earth visit both Vesta and Ceres in the next decade. Dawn is the first probe designed specifically to visit main belt asteroids. It has been a troubled mission, delayed by financial and technical problems; in fact the whole Dawn mission has been cancelled and resumed twice.

Ice Dwarf Ceres as viewed by the Keck Observatory at Mauna Kea, Hawaii. Ceres is 980 km across its equator. Its average distance from the Sun is about 2.8 AU elements making up the outer part of its targets and a mapping spectrometer which operates in the visible and infrared wavebands to reveal how minerals are distributed across the surfaces of Ceres and Vesta. Dawn's most innovative feature is its propulsion system. Most preceding interplanetary probes, after an initial rocket boost coast gradually across the Solar System to their destinations. Dawn, instead, will cruise under continuous thrust from its ion engines. In these devices electric energy is used to accelerate xenon fuel, applying a very gentle but continuous thrust. As a result the spacecraft eventually attains speeds much greater than possible with chemical rocket motors. It

"Dawn will cruise under continuous thrust from its ion engines"
There is seldom a true sense of scale in artist's impressions and computer-generated renderings of space probes. It is easy to visualise our robot explorers to be dinky little machines, no bigger, say, than a small car. This usually is not the case, and Dawn is especially big. Its solar panels span 19.7 meters (65 feet) from tip to tip, almost as long as a cricket pitch. Its science payload includes a pair of cameras, a gamma ray and neutron spectrometer used to pin down the
Image Credit: NASA

Dawn in flight as portrayed by a NASA artist, showing the plume of ionised xenon from its engines. The stylised background shows Vesta (left), Ceres (right), numerous small asteroids and the Solar Nebula which gave rise to them all.

Image Credit: NASA


4 Astronotes September 2007 is a very fuel efficient propulsion system, so the spacecraft can be smaller without massive fuel tanks. Ion propulsion has been applied before, notably to the Deep Space 1 and SMART 1 vehicles, but the Dawn mission its most creative application so far. After launch in September 2007, the probe will move away from Earth in a slow, lazy spiral until it receives a gravity assist as it flies by Mars in March 2009. It will cruise onwards until it goes into orbit around Vesta in October 2011. Dawn will spend six months scrutinizing the asteroid before firing up the ion drive and proceeding to a February 2015 arrival at Ceres. At the moment the plan is to spend the rest of the mission at the dwarf planet, but there is always the chance that the mission could be extended to permit visits to other members of the Asteroid Belt. So in less than a decade we will have explored two new worlds and possibly learned more about the origin of the Solar System. We live in great days.

Moon Phases, Sept 2007
Tues Tues Wed Wed 4 September 11 September 19 September 26 September Last Quarter NEW MOON First Quarter FULL MOON

Great Astronomers: Tycho
By Naomi Francey, Education Support Officer Tycho was a Danish astronomer born in 1546 and can be credited with making the most accurate astronomical observations of his time. He was assisted by Johannes Kepler (see May issue of Astronotes) from 1600 to 1601 who later used his research to develop his laws of planetary motion. Tycho began his education in Copenhagen and followed the desires of his uncle and studied law. However, he also studied other subjects, including astronomy, and this is where his interest began. Tycho had a brilliant mind and by the age of 17 he already had an aim to map the heavens conducted from a single location over a period of several years.

"Tycho also had his insane moments!"
Tycho's main achievements included his ability to catalogue the planets and stars with enough accuracy, to determine whether the Ptolemaic system, in which the Earth is the centre of the universe and the Sun and other objects go

The Man with the Golden Nose Tycho had the precious-metal nasal prosthetic installed after losing his original nose in a sword fight. So how did he smell? Probably awful! around it, or Copernican system, where the Sun is the centre of the Solar system was more valid in describing the heavens. He measured the Earth's axial tilt as 23ђ 31.5 minutes which he claimed to be more accurate than Copernicus by 3.5 minutes.

Image Credit: via wikimedia.org


September 2007 Astronotes 5 A great astronomer he was, but he also had his insane moments! At the age of 20 Tycho lost the bridge of his nose and it was said that he wore a replacement made of gold or silver blended into a flesh tone for the remainder of his life. Although historians have argued that it was more likely to be copper, as it would have been more comfortable to wear than precious metals. He was also fond of a drink, and apparently he used to have a dwarf as a jester and an elk as a pet, which sadly died after drinking beer at one of his parties and fell down the stairs! There has also been speculation about the death of Tycho. It is thought that Tycho died from mercury poisoning as toxic levels were found in his hair and hair-roots. He may have poisoned himself unintentionally consuming some medicine containing mercury. There are also rumours that he was murdered by Kepler (see Joshua Gilder and Anne-Lee Gilder's book `Heavenly Intrigue') although there is no evidence to support this. Despite his eccentricities, he was a great astronomer whose research has contributed to a further understanding of astronomy today.

Is there anybody out there?
By Wendy McCorry, Science Communicator
Image courtesy of National Radio Astronomy Observatory/ AUI/NSF

Do aliens exist? This is perhaps the most common question asked by visitors to the planetarium. Admittedly it is usually asked by our younger visitors who have no idea that such a question could be at all laughable - they simply want to feed their curiosity. The reply given is a steadfast, "Well, we can't rule out the possibility of life on other planets but as yet we have found no evidence..." This inevitably leads to a look of disappointment, as all the child really wants to hear is that yes, some night he might look outside to see a one eyed little green man climbing out of a flying saucer in his back garden.

"Drake estimated that there were ten civilisations in the Milky Way"
Adults seldom ask the question, but if they do they pretend to be joking, in case you should repeat their query too loudly in front of another grown up. Let's face it, we'd all like to know the

Frank Drake by the Green Bank antenna. Born in 1930, Dr Drake is a major figure in the field of radio astronomy, but is probably best-known for his SETI work. answer, but most of us are too embarrassed to ask. One man who was not too embarrassed to ask, however, was Frank Drake. In 1960, whilst working as a radio astronomer at Cornell University, Drake performed Project Ozma, the first modern SETI (Search for Extra-Terrestrial Intelligence) experiment, using the 25m diameter Green Bank radio telescope in West Virginia to search for signs of extra-terrestrial transmissions from


6 Astronotes September 2007 the stars Tau Ceti and Epsilon Eridani These stars were chosen because they were located near the Solar System, and fairly similar to the Sun. Although the experiment yielded no positive results, it was the start of a hugely popular SETI movement which continues to this day. At the heart of SETI is the belief that if there are hundreds of billions of galaxies, each containing hundreds of billions of stars and billions of planets, surely there is a distinct possibility of intelligent life out there. In 1961, Drake attempted to put this question into scientific terms by assigning values to all its relevant influencing factors. This is known as the Drake Equation and reads as follows: N = R* fp ne fl fi fc L N is the number of communicating civilizations in the galaxy R* represents the average rate of star formation in the Milky Way Galaxy fp is the fraction of those stars that have planets around them ne is the number of planets per star that are capable of sustaining life fl is the fraction of planets in ne where life evolves fi is the fraction of fl where intelligent life evolves fc is the fraction of fi that develop the technology to release electromagnetic communications L is the lifetime of the communicating civilizations Frank Drake's own solution to the equation estimates that there are ten communicating civilizations in the Milky Way: Aliens! Is this the last censored image from Beagle 2? No, it is just some of the wonderful creatures created by young visitors to our craft room. Drake's values give N = 10 Ѕ 0.5 Ѕ 2 Ѕ 1 Ѕ 0.01 Ѕ 0.01 Ѕ 10,000 = 10 Drake believes that the value of the equation is not in the answer itself, but in the questions which arise when attempting to calculate each of the variables. He hopes that with increased knowledge from the fields of astronomy, biology and other sciences, the amount of guesswork required in reaching each of the values will be reduced and replaced by a more realistic estimate. Progress is already being made towards this goal, with the discovery of other solar systems within our galaxy, and the existence of possible Earth-like planets such as the much publicized Gliese 581c. Why not try to calculate your own answer for the Drake Equation? Bear in mind that your answer should not be less than one, otherwise you will have proved what many of us have long suspected - that intelligent human life does not exist!

Global Hands-On Universe Conference 2007
By Robert Hill, NISO This year the annual gathering of scientists, teachers and those involved in astronomical education and outreach activities for the Global Hands-On Universe (GHOU) conference took place in Japan. The hosts for this year were

the Japan HOU delegation and the National Astronomical Observatory at Mitaka. Over five days the delegates discussed important issues for astronomy research and education collaboration with emphasis on experiences and current achievements in educational and research

Image Credit: Armagh Planetarium


September 2007 Astronotes 7 Gunma Observatory, an hour and a half by coach from Tokyo. This research observatory encourages dialogue with the Japanese taxpayer through public observation nights at the facility. And what facilities they have! The 1.4 metre telescope is primarily used for research but once a month it is opened up to the public. The telescope has several eyepiece positions for observations for all heights and a special device for those wishing to view from a wheelchair. However, even more impressively, the Gunma staff has provided an entire building devoted to the public which is more like something from "Thunderbirds" than an observatory!
Image Credit: Robert Hill, NISO

Our Man in Japan Robert visits the incredible public observatory at Gunma Observatory projects from each region or continent. The UK delegation comprised of Dr Sarah Roberts and myself, representing the Faulkes Telescope Project and UK/European HOU respectively. Representatives from every participating nation explained how they had engaged with authorities in their region to develop astronomy and space science educational culture, to varying degrees of success. Delegates were very impressed by the work of Armagh Planetarium and NISO with respect to the integration of these subjects into core elements of the newly revised curriculum in Northern Ireland with several collaborations now being discussed to begin the process in Thailand and Pakistan.

"Gunma is more like something from Thunderbirds than an observatory"
There were two main highlights for me personally. The first was the session devoted to school pupils from Japan who had created research projects with their peer groups. The standard of every presentation and poster from these fifteen year old pupils was outstanding (and explained in perfect English!). Projects with titles such as `Photometric observations of the cataclysmic variable star IP Peg' presented by students from Rakuto High School made for some really inspirational moments and also had some of our professional astronomical colleagues having to put their thinking caps back on! The other highlight must be the visit to the

Proud Pupils Kasumi Goto and Ayano Terada show off their research paper The entire building has an electronic roof which slides back to reveal several electronically controlled Takahashi telescopes on specially designed mounts used for public viewing. If is safe to say that all delegates were astonished at the service that was being provided by the Japanese Government for the public and the Japanese astronomers and communicators have set a really high standard for us all to follow. It was a very memorable and worthwhile trip!

Image Credit: Robert Hill, NISO

GHOU delegates at National Astronomical Observatory Japan

Image Credit: Robert Hill, NISO


8 Astronotes September 2007

IPS Council meeting at Rio
By Tom Mason, Director At the recent International Planetarium Society Council meeting which was convened in Rio de Janeiro, I attended as the representative of the British Association of Planetaria, as well as in my capacity as President-Elect of the IPS. One of the most important items of Council business was to decide on the venue for the 2010 IPS conference, and we listened to presentations from St Etienne in France, Beijing in China and Alexandria in Egypt. Following these detailed explanations of how each venue proposed to run a major conference event, the Council voted, and Alexandria is the chosen venue for 2010. We also heard an update from the Adler Planetarium on the progress of the Chicago conference, which will be held in the middle of next year. The meeting was convened in Brazil as it offered an opportunity for the Brazilian Planetarium community to apply to become affiliate members of the IPS while showing off their subtropical city to the IPS Council visitors. This application was successful, and Rio astronomer Alexandre Cherman is the new Brazilian affiliate representative. Our Brazilian hosts showed us all of the classic sites of their famous city, the well-known icon of the Corcovado peak, with its massive statue of Christ the Redeemer dominates that city
Image Credit: Fundaчуo Planetсrio da Cidade do Rio de Janeiro

skyline, and the cable car to the top of the Sugar Loaf Mountain allows panoramic views over the coastal setting of Rio, and its famous beaches of Botofogo, Copacabana and Ipanema. Rio de Janeiro is a city of around 12 million inhabitants. At the moment it is served by one Planetarium housed in the suburb of Gavea which is part of an impressive Museum of astronomy and space. There are robotic telescopes on the roof and four telescope domes that can be used for public events. They have around 700 000 visitors each year. A planned refit of the Planetarium is scheduled to include a new digital projection system and the city authorities are seeking bids from all of the main suppliers. Still in the planning stage, a second planetarium is scheduled to open soon to serve the western part of the Rio metropolis as, like every other society wishing to strengthen their science base, the local authorities have decided that the best way to attract youngsters into science is to give them an achievable target, and becoming a scientist with an interest in space exploration pushes all of the right buttons. Rio's 277 seat main Planetarium is a steeply tilted dome with a centrally mounted Zeiss Universarium 8. This is the primary dome and it is supplemented by a smaller 130 seat planetarium equipped with a 1970's vintage Zeiss Spacemaster: this is the staff astronomers' favourite venue which they use to teach visitors about the constellations. During our visit the Sunday lunchtime opening featured a live performance, a concert with harpsichord and percussion, which adapted the classics of Scarlatti and Villa Lobos to reflect the distinctive Brazilian musical flavour. Regrettably like all large urban settings there is so much light pollution that observation of the southern skies is restricted, but as a venue for visitors Rio and its planetariums has a lot to offer: an added benefit is that the winter temperatures during the daytime were around 22 н 27ђ C!

Rio's planetarium showing the imaginative paint job on its larger dome. The smaller dome to the left houses the original planetarium.


September 2007 Astronotes 9

New Astronomy Courses
By Colin Johnston, Science Communicator This autumn, Armagh Planetarium, in conjunction with the Queen's University of Belfast School of Education and the Tara centre in Omagh, will be presenting beginners' courses in astronomy to be held in Belfast, Randalstown and Omagh. The Night Sky will consist of a series of five lectures at the QUB School of Education. This course is aimed at absolute beginners who want to know how to tell one constellation from another or point out planets or satellites. If you want to know more about the amazing objects visible in the night sky, this course is for you. The course will concentrate on objects visible to the naked eye (no equipment needed). An Introduction to Astronomy will be presented for QUB at St Benedict's High School, Randalstown and Astronomy for Beginners will run at the Tara Centre, Omagh.These ten week courses (note that the content for each course is identical despite the different titles) will cover our knowledge of the Universe and the wonders it contains. The courses are aimed at those new to the field and will be descriptive rather than mathematical, following human understanding from prehistoric times to the latest discoveries from spacecraft. No prior knowledge is required. Towards the end of all of the courses there will be an optional session held in Armagh Planetarium. For more details see www.armaghplanet.com. To enrol: contact Queen's University Belfast School of Education (Tel: 028 9027 3323) or Tara Centre (Tel: 028 82 250024)

What on Earth is up with our Weather?
By Naomi Francey, Education Support Officer Rain, rain, rain and more rain! This seems to be the summer that we are experiencing in the United Kingdom and Ireland! Widespread flooding is devastating many low lying areas, forcing people out of their homes and contaminating drinking water. So what is behind this insane weather that we are having? It seems that a band of low pressure has been positioned over the UK for months, which has forced the North Atlantic jet stream south of the UK, in a normal summer it is above the UK. The Jet Stream is an air current that moves from west to east, in our case across the Atlantic. Jet streams form when air streams of different temperatures meet, for example, polar air and warmer southern air. The different air streams do not flow easily over each other due to the differences in pressure, and the wind moves along the boundary of the hot and cold air driven by the Coriolis force, a result of the Earth's rotation. When the air pressure is lower than the surrounding area, it gives bad weather and when the air pressure is higher than the surrounding area (called an anticyclone) we receive good weather. A typical British summer usually has an anticyclone over the country which provides us with warm, sunny, normal summer weather. But because of this blocking low pressure we have been experiencing an unusual amount of rain this summer, and I use the word summer loosely. Figures from the World Meteorological Organisa-


10 Astronotes September 2007 tion show that from May to July 2007 England and Wales experienced the wettest weather since records began in 1766. Our urbanised landscapes, building on flood plains and increasing infrastructure creating more impermeable surfaces meant that the drainage was inadequate, leading to intensive flooding and unfortunately taking nine lives. With more rain on the way this chaos is unlikely to solve itself.

There has been speculation that this wet summer will now be the norm due to climate change. The Met Office Hadley Centre has predicted that from 2004 to 2014 the average global temperature will have increased by 0.3ђ C. In the past 100 years the world has warmed by 0.8ђ C, so this is a steep increase. These temperature increases are an average, so if central Europe keeps experiencing very hot summers with Western Europe having normal air temperatures this could keep the jet stream below the UK. Only time will tell whether this will be the case! But I wouldn't hang up your raincoat Drowned World this image of Gloucester, England, shows the River just yet! Severn and captures the extent to which it has flooded its banks.

Image Credit: NASA/Earth Observatory

Exploding the asteroids!
By Colin Johnston, Science Communicator NASA engineers have designed a nuclear-warhead-carrying spacecraft intended to ward off asteroids or comets that threaten to collide with Earth. Asteroids and comets whose orbits bring them close to Earth's orbit are termed Near Earth Objects (NEOs). We know that NEOs have collided with our planet throughout its history, with often cataclysmic results for Earth's inhabitants. If want to know just how bad such a collision can be, ask a dinosaur about the impact 65 million years ago (There aren't any dinosaurs to ask? Rather answers the question, doesn't it?) It is a good idea to plan ahead for such an unlikely eventuality. Apophis is a 46 million tonne asteroid discovered in 2004 which regularly passes by Earth. On Friday 13 April 2029 (Friday the 13th!), Apophis will whizz past the Earth closer than most communication satellites before returning for another close Earth approach in 2036. Just how close it will come on its later visits is worryingly uncertain (it is very unlikely to hit us, but it would be reassuring to say for certain that it will miss). According to Flight International magazine, a NASA study has posed the question of what could be done if we knew that Apophis was going to collide with Earth. The solution may require the strangely-named pilotless spacecraft, Cradle, and the deadliest cargo ever carried into space. The Cradle spacecraft would be 8.9 m long and be launched on NASA's planned but unbuilt moon rocket, the Aries V. Powered by solar arrays, the spacecraft would use both a laser detection and ranging (lidar) instrument and cameras to navigate to the vicinity of the intruder. Cradle's payload would be six interceptor vehicles each of which is tipped with a 1.2 megatonne


September 2007 Astronotes 11

Nuclear Space Bomber In the isometric view the Interceptors are not shown for clarity. nuclear warhead. In this context `megatonne' is the weight of conventional explosives the exploding device would be equivalent to. Each warhead's detonation would be comparable to 1.2 million tonnes of TNT which is almost a hundred times as devastating as the atomic bombs dropped on Japanese cities in 1945. but NASA once considered building a crew-carrying spacecraft utilizing this principle (see the December 2006 Astronotes). Cradle would be preceded by a 1.5 tonne observer spacecraft (based on the 2005 Deep Impact comet probe) which would explore the NEO to determine its composition. This is important as there is evidence that the consistencies of NEOs varies from solid nickel-iron to piles of loosely bound dust as delicate as cigarette ash. If we know what to expect the nuclear option may not be required and a less drastic solution could be used. These alternative options to push away the NEO include ramming it with a fast-moving but non-explosive projectile or using a vast but light-weight solar mirror to focus sunlight and melt part of the surface. In both cases the thrust of vaporized surface material escaping would nudge the NEO from its collision course. By the 2020s NASA hopes that spacecraft of the Cradle-type could deflect NEOs of 100500m diameter as long as there was two years warning. Larger NEOs would need at least five years warning. This is one future space mission nobody wants to see launched!

"The warheads would explode and vaporize a layer of the surface"
Unlike the Hollywood version of Earth-protecting missions, the intention is not to blast apart the NEO (even these six large bombs would not be enough) but instead to deflect it. A modest push months ahead of the day of impact would cause the asteroid to miss Earth by thousands of kilometres. To facilitate this, the interceptors would be launched at hourly intervals when Cradle is still more than four days from its target. The warheads would explode above the NEO's surface and the radiation from each detonation would vaporize a layer of the surface. The force of this white-hot plasma surging outwards will hopefully deflect the NEO. It may seem unlikely

Image Credit: Flight International via www.flightglobal.com


12 Astronotes September 2007

Image of the Month
By Jupiter! As New Horizons sped past Jupiter on its way to Pluto, its science instruments were briefly tested. One of this instruments is a multi-spectral imager nicknamed Ralph. This was its view of Jupiter's high-altitude clouds on 28 February 2007, as the probe made its closest approach. The image was taken at an infrared wavelength that is strongly absorbed by methane gas, so the image appears slightly washed out. The familiar striped appearance of Jupiter is a product of its fast rotation, dividing the Jovian upper atmosphere into dark belts separated by light-coloured zones. Belts appear to be regions of descending gas and the zones are regions of warmer rising gas. These are moving in opposing directions; at the interface between a belt and zone the speed differential can approach 500 km/h! Jupiter's belts and zones are visible in small telescopes and the planet has been prominently visible in the southern sky through the summer making an interesting pair with Antares. However as the year moves on Jupiter will become harder to see as so catch it while you can. Look for it in low in the south west. (Caption by Colin Johnston, Science Communicator)

Image Credit: NASA / JHUAPL / SwRI

www.armaghplanet.com
Astronotes, Incorporating Friends' Newsletter is published monthly by Armagh Planetarium, College Hill, Armagh, Co. Armagh BT61 9DB Tel: 02837 523689 Email: cj@armaghplanet.com Editor: Colin Johnston й2007 Armagh Planetarium All rights reserved