WHAT'S UP  ON-LINE

 The Electronic Journal of the Macclesfield Astronomical Society

Editor : John H Thomson

e-mail : jhandlc@thomson.u-net.com

Credit: NASA, Harold Weaver (the Johns Hopkins University), and the HST Comet LINEAR Investigation

In one stunning Hubble picture the fate of the mysteriously vanished solid nucleus of Comet LINEAR has been settled. The Hubble picture shows that the comet nucleus has been reduced to a shower of glowing "mini-comets" resembling the fiery fragments from an exploding aerial firework. This is the first time astronomers have ever gotten a close-up look at what may be the smallest building blocks of cometary nuclei, the icy solid pieces called "cometesimals", which are thought to be less than 100 feet across. The farthest fragment to the left, which is now very faint, may be the remains of the parent nucleus that fragmented into the cluster of smaller pieces to the right. The comet broke apart around July 26, when it made its closest approach to the Sun. The picture was taken with Hubble's Wide Field Planetary Camera 2 on August 5, 2000, when the comet was at a distance of 64 million miles (102 million kilometers) from Earth.

Contents
 

• Chairman's Column                          -   Alan Smith
• Secretary's news
• Perseid meteor watch                         -    Dave Ogden
• What's New ?                                    -    Latest Bulletin from The SPA
• Italian Astronomy - Elba 2000             -     John Thomson
• Astrophysics at University                     -     Megan Argo
• Minor Planet Alert                                   -     Roger W Sinnott ( Sky & Telescope)
• Sky Diary                                          -    John Thomson
• Lecture list 2000 - 2001

Chairman's Column

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The Learning Curve.

 Whatever the reason, you have decided to expand on what was merely a passing interest in astronomy by taking that "giant step for mankind" and joining the local society. If you are an absolute novice (and remember we all were once), you enter a curious world of unfamiliar jargon, confused even more by the astronomic fraternity's annoying habit of abbreviating the various terms down to their initial letters. For the more elderly novice, there is the problem of remembering the mathematics of your youth that has either been forgotten or has become extremely rusty by long years of neglect.

 At this point, therefore you enlist in the "Beginner's class" in an effort to rectify these apparent shortcomings, only to find that you have joined halfway through the "school year" and the topics in which you are interested or those of most use, were dealt with several months previously.  Life does seem beset with problems!

 However, eventually you become conversant with the quaint and curious idioms and the basic astronomical concepts, feeling confident enough to venture into the great outdoors and turn your face upwards towards the "big, big sky". Not quite! Despite having in your possession the most modern and comprehensive Star Atlas that money can buy, you find the following problem: since publication, some foul fiend has not only turned the constellations upside down, but has filled the "spaces" with sufficient stellar material as to apparently render your star map as undecypherable as an M.F.I. instruction sheet! But by the application of true diligence, accompanied by the occasional profane expletive, you will now be on par with the Ancient Mariner in terms of the cosmic "where"!

 At this stage, yet another problem raises its ugly head, one that can seriously damage your wealth! That is of course, the procurement of a suitable optical instrument to further your scientific aspirations! Many of the "old stagers" will have recommended the purchase of a pair of ubiquitous 7 x 50 binoculars. This is sound and well tried advice so follow it; the "glasses" are cheap, will last a lifetime, can be used for other activities and have the advantage of providing "thinking time". Consider that if it has taken several millennia for the light of a distant star to reach earth, then the delay of a few months to decide on your choice of the perfect telescope pales into insignificance.

Next month I will endeavour to assess the problems to be addressed in the selection of your ideal personal telescope.

 I leave you with a possible solution to the ultimate astronomers' problem!

 "In order to maintain one's "sang froid" when the vaguaries of the British climate completely blot out and obliterate that once in a lifetime event, I would recommend reading Marcus Aurelius's treatise on Equanimity."
 
 

Secretary's news

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 Attendance at meetings continues to grow, reaching a figure of 121 in August. There are now 179 members of the Society, making it one of the largest in the country. We always offer friendly advice and information to those who contact us, and we continue to encourage and support the growth of knowledge about the Universe in as many ways as possible.

 A reminder for members that fees for the coming year are due this month and Jack, as acting Treasurer, will be glad to see you with your cheque-books after the lecture. Another important reminder is that the AGM will be held on 7th. November at 8.00 pm, so there will be no lecture that evening. However, items for the agenda and nominations for the committee must be received by the meeting on 3rd. October.

 Finally, don't forget your copy of the Y2K 'Year Book', priced £3.50, available at coffee time.
Don't miss out !
 

 Contents

The Perseid Meteor Shower in August 2000                   by Dave Ogden

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At last we can report that we had some considerable success on a meteor watch night. The preceding week had given us a taste of what might happen if the sky was clear on the Friday night of the shower Maximum. On at least two or three evenings, members including (on different nights) Steven Tate, Andrew Greenwood, Chris Hall, Andy Carroll and myself had gathered at Langley Cricket ground. This site is slightly more accessible than Gradbach, but not quite as dark.

On the night of the monthly lecture, the skies were very clear for at least an hour or two and much binocular messier spotting was indulged in. There were good views to be had of many objects and several meteors were noted. Some were sporadic but others were clearly precursors of the main Perseid stream. Chris Hall, who is a considerable meteor enthusiast (or mad!) drove home from Jodrell Bank to Stoke, and then back to Langley so that he could have the appropriate equipment for recording his observations.

While the rest of us were musing on the limiting magnitude of that site, a gentleman driving up the road nearby, decided that he must stop very quickly for some reason. The noise of squealing tyres caused us all to investigate. To our astonishment, smoke was rising into the air from the lane. As we approached the car, the driver just as suddenly restarted his Ford Ka and drove off quickly. He left 60 ft long skid marks on the road. We could only conclude that he had seen something strange ahead. Perhaps a wallaby or maybe just a badger. He certainly didn't want to talk to us about it! It's strange what you see when you are under the stars.

We returned to our observations and eventually Chris Hall reappeared after his 50 mile round trip - just as the cloud arrived. That's English astronomy for you. The others met again later that week and the next and were blessed with some more good skies.

On the evening of the 11th, the bush telegraph swung into operation and internet weather satellite images were discussed. The images showed that a huge area of clear sky was going to remain over the North throughout the night.  It was indeed a very good clear sky over Gradbach and we saw plenty of meteors throughout the night. Chris rated the frequency of Perseids to be about 22 per hour. Many were bright and there was plenty of action to keep people interested.

As the morning deepened, we were blessed with some superb seeing and of course, the rising of Saturn and Jupiter. With my 8" Celestron, we could easily see Saturn's ring shadow and the Cassini Division. We also reckoned we could see the Crepe Ring. Would anyone like to confirm that they have also been able to observe this with an 8" and report back to me.

Altogether, I think twelve members turned out. Members present included Peter Molinari, Russel Fowden, Ian Longshaw, Gordon Watkin, John Treacy, Megan Argo, Gill Riseley, Chris Hall, Steve Tate, Andrew Greenwood and myself.
If I missed anyone, I apologise, it isn't easy to count people in the dark, they keep moving about!

Five of us remained until Dawn, taking advantage of the excellent pre-dawn seeing. Altogether it was an excellent observing session.

Cheers

WHAT'S NEW ?                     SPA Bulletin

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British SPA observers enjoyed some very helpful skies in the build-up to the Perseid maximum this year. Meteor watch data was reported to us from every night except five between July 19-20 to August 11-12 inclusive, virtually unparallelled for the last 17 years! August 11-12 saw the best Perseid activity visible from the UK, when large parts of England especially had mostly clear skies, observations hampered only by the bright waxing gibbous Moon, which set soon before morning twilight began. Zenithal Hourly Rates (ZHRs) averaged about 75 +/- 10 for August 11-12 as a whole, but rose from ~55 after dusk to ~85 near dawn. Though bright as always, few Perseid fireballs (meteors of at least magnitude -3) were spotted on this night, the brightest so far of magnitude -6 at 00h37m UT on August 12.  reliminary results from 49 International Meteor Organisation observers around the globe indicated no sign of the primary Perseid maximum in 2000, seen in every year since 1988 before this. The "traditional" peak, when the highest ZHRs (~110-120 +/- 10) this year were detected, occurred at about 10-11h UT on August 12, much as expected. The figures quoted here are naturally subject to revision as more data arrive, and if you have still to send in your Perseid observations, please do so as soon as possible.

LINEAR'S MINI COMETS

NASA's Hubble Space Telescope has discovered at least half a dozen "mini-comets" left behind from what had been thought was a total disintegration of  Comet LINEAR following its passage around the Sun on July 26. The results support the popular theory that comet nuclei are really made up of a cluster of smaller icy bodies called "cometesimals". Since the 1950s, comet nuclei have been commonly assumed to be loose agglomerations of ice and dust - "dirty snowballs" weakly held together by gravity. By investigating how Comet LINEAR is coming apart, astronomers hope to learn how it was put together in the first place, roughly 4.6 billion years ago. A notable isolated brighter piece in front of the cluster may be the parent nucleus for the smaller fragments. JPL, reports: "The unusually large nongravitational forces suggest that comet LINEAR was a trailing fragment of a more massive comet that has been moving in the same orbit, arrived at perihelion centuries ago but was missed." Trailing fragments of known comet pairs have a tendency to sudden disintegration. The total mass dissipated into the cloud of dust in the recent event, could be estimated by further monitoring the tail.  Experience with past initially bright comets that later became headless and disappeared shows that a narrow, bandlike tail should survive the head by several weeks or even longer  A preliminary analysis suggests that the event may have begun as early as July 23.  Astronomers believe that the reason the comet disintegrated was because all the ice in its nucleus evaporated, leaving behind a loose conglomerate of particles that are now gradually dispersing into space.
 

LIGHT FROM PLANET WAS FALSE

Astronomers who claimed they had detected light reflected from a planet orbiting the star Tau Bootis have admitted they were wrong.  St Andrews University say they had been misled by "random noise" in the data they had been studying.  Detecting light from such a planet would have been a breakthrough. Astronomers hoped to analyse the light, deduce the planet's properties, and possibly look for evidence of life.
 

STUDENTS FIND CENTAURS

Two students using the Spacewatch telescope have discovered five Trans Neptunian Objects (TNO's), three Centaur asteroids and two 'scattered disc objects'. Two of the asteroids crossed planetary orbits like Centaurs and travelled out much farther than Pluto. Based on these two discoveries, the Centaurs and scattered disc objects are now considered a single class of asteroids.   What intrigues astronomers is their peculiar location in the solar system. They are at the same distance from the Sun as protoplanetary discs surrounding very young stars, such as Beta Pictoris. By mapping Centaurs and TNOs, learning how abundant they are and how they are distributed, theorists hope to form a model of how the solar system came into existence. Also, the physical rules that triggered the solar system's formation and how long that process took remain a mystery. Hidden near at the periphery of the solar system, many TNOs have not been influenced by the gravitational forces of planets, especially Jupiter.  Their orbits may represent the original configuration of matter in the very early solar system.   Whatever the original protosolar nebula was doing, the TNOs probably have some signature of it left in their orbits.
 
 

NOVA MECHANISM UNDERSTOOD

In 1996 amateur astronomers discovered an outburst taking place in SS Cygni, a close binary star system containing a red dwarf star and white dwarf star.  NASA scientists were able to immediately reposition its Extreme Ultraviolet Explorer satellite (EUVE) and its RXTE satellite to observe the entire event in full.  The outburst is caused when the dense white dwarf pulls a stream of gas from its companion star forming an accretion disk.  The dramatic brightening that occurs is the result of an instability in the disk, which forces the disk material to rain down onto the surface of the white dwarf, causing an enormous release of energy equivalent to billions of atomic bombs exploding every second. Such stellar explosions, which often occur without warning and rarely last more than one or two weeks, serve as flood-lights that brighten a dim star system for scientists to study.  A four year analysis of the observations has now been completed.  The optical, EUVE and RXTE observations show that a white dwarf outburst starts with the radiation of visible light, which comes from the outer part of the accretion disk. The radiation changes its character about a day later, and X-rays are observed. Extreme ultraviolet radiation is detected when the gas flow reaches the white dwarf. The dramatic switch at the beginning of the outburst from X-ray to extreme ultraviolet emission is the result of a drop in the temperature of the boundary layer between the accretion disk and the white dwarf from one hundred million degrees to a hundred thousand degrees Kelvin.  The increased density around the boundary allows the region to cool.  This transition has never been observed before.
 
 

JODRELL BANK TO STAY OPEN

Rumours that the Jodrell Bank radio telescope will have to close if Britain joins the European Southern Observatory are untrue according to PPARC.  They have given assurances that the planned upgrading of the dish will go ahead and have guaranteed funding for a further five years.
 
 

SHORT PERIOD COMETS ARE NOT ANCIENT

Studies of the Edgeworth-Kuiper belt by the Southwest Research Institute have revealed that most short-period comets - those comets with orbits of less than 200 years and which are known to originate in the Edgeworth-Kuiper  Belt - are recently created fragments from collisions between the larger icy objects in this region, not ancient relics as previously thought.  It also says that early in the solar system's history, the Edgeworth-Kuiper  Belt was apparently 100 or more times more massive and populous than it is  today.
 

WATER MYSTERY

NASA's Submillimeter Wave Astronomy Satellite, or SWAS, has detected water vapour throughout interstellar space. However, in the very coldest reaches, where temperatures are found just 30 degrees above absolute zero, astronomers measured water vapour concentrations of only a few parts per billion.  That's far less than predicted by most theories and presents a real puzzle to our understanding of the chemistry of interstellar clouds. In warmer regions of space, though, water vapour is more plentiful. Within gas clouds where new stars are being born, the gas can be heated to temperatures of several thousand degrees ; here the water concentration seems to be as much as 10 thousand times larger.  The large amounts of water vapour present in regions of star formation will help the interstellar gas to cool, perhaps eventually triggering the birth of a future generation of stars.  Because of our belief that water is an essential ingredient for life, the search for its presence in interstellar gas clouds has always attracted particular attention and that's why these results are intriguing.
 

UNVEILING THE BIRTH OF STARS AND GALAXIES

British astronomers have announced the first results of a new sky-survey at submillimetre wavelengths, which unveils the birth of galaxies and the rates of star formation through the history of the Universe. They have found a way to demonstrate that, when we observe at submillimetre wavelengths and look for galaxies, we mainly find very distant star-forming galaxies. Two thirds of all the energy ever generated in nuclear processes in stars is emitted as submillimetre radiation, so observations at these wavelengths are vital for tracing the history of star formation in the Universe. The team uses the UK's SCUBA submillimetre camera on the James Clerk Maxwell Telescope in Hawaii to look for relatively bright sources emitting radiation at a wavelength of 850 microns. So far, the first sources studied in this way cannot be seen at all on deep images taken with ordinary visible light. This demonstrates that they are incredibly distant galaxies, at high redshift. For the first billion years of the life of the Universe, the star formation rate in galaxies increased steadily to a level over ten times higher than it is today. It continued at that rate for several billion years. By the time the Sun and Earth formed 4.5 billion years ago, the rate of star formation had dropped to only about 3 times what it is today.
 
 

GIANT RADIO TELESCOPE PLAN

Astronomers from Europe, North America, Asia and Australia have signed an agreement jointly to plan a huge new radiotelescope, the Square Kilometre Array (SKA), which will come into operation in the middle of the next decade. Its collecting area will be almost 100 times larger than today's biggest radio imaging telescope. SKA's superior resolving power and exceptional image quality will provide crucial new information on the formation and early history of stars, galaxies and quasars, unaffected by obscuring dust. Its enormously high sensitivity will mean that, an object detected by another telescope can also be studied at radio wavelengths. The goal is to reach agreement on the fundamental design of SKA and its location by 2005 and to begin construction in 2010.
 
 

ENGINE SETS FLIGHT RECORD

NASA says that its futuristic engine on an experimental spacecraft has racked up more operating time in space than any previous propulsion system, Deep Space 1, designed to test a variety of new technologies, has zoomed through space using an ion drive propulsion system for more than 200 days.  Other spacecraft have been in space for a long time, but they don't run their propulsion systems very long.  Unlike traditional chemical rockets that blast out hot exhaust, an ion drive emits only an eerie blue glow as ions, or electrically charged atoms, exit the engine. The source of the ions is xenon, a gas found in fluorescent tubes and lighthouse bulbs.   The hardly noticeable thrust from the ions exerts about the same amount of pressure as a sheet of paper held in the palm of one's hand. While slow to pick up speed, ion propulsion creates substantial power over great distances, delivering 10 times more thrust per pound of fuel than conventional rockets. The importance of ion propulsion is its great efficiency. It uses little propellant, which means the spacecraft weighs less, can use a less expensive launch vehicle and go much faster than other spacecraft.
 
 

SWEEPING UP SPACE DEBRIS

NASA engineers worried about debris hitting the International Space Station have devised a laser "broom" to clear a path in front of it. Known as Project Orion, it will sweep up space debris the size of tennis balls and will be tested on a Shuttle Mission in 2003.  NASA claims that unless some of the debris is removed, there is a 1 in 10 chance that the International Space Station will be holed during the next ten years.
 
 

MARS ROBOT PLANNED FOR 2003

NASA has announced plans to send a six-wheeled robot weighing seven times more than the successful Mars Sojourner of 1997.  It will study the geology of the planet and in particular search for evidence that water once existed on Mars.
 
 

NEW PLANET ORBITING EPSILON ERIDANI

Astronomers from The University of Texas have discovered a new planet orbiting the star Epsilon Eridani which lies only 10.5 light-years away from Earth. The planet is roughly the distance from the Sun to the asteroid belt in our own solar system and has a mass somewhere between 0.8 times the mass of Jupiter and 1.6 times the mass of Jupiter.  Its orbit lasts just under seven years -- about 60 percent the orbital period of Jupiter but longer than that of most other recently discovered planets. Astronomers are excited about the new planet's rough similarity to Jupiter, because they believe Jupiter played an important role in the development of life on Earth by protecting it from comets.  Any Earth type planets orbiting Epsilon Eridani would have similar protection.
 

PLANETARY PATTERNS

The total number of known planets outside our solar system is now 44 and a team of astronomers at the University of California is beginning to see patterns, including hints that many extrasolar planets may have siblings. Nearly 50 percent exhibit unexplained wobbles that could result from the tug of a companion, whether another planet, an unseen star or something in between, making it the first time anyone has noticed that such a high percentage of stars with one known planet show evidence of a second companion.
 

HUBBLE STUDIES GLOBULAR PLANETARY

The Hubble Space Telescope is studying a planetary nebula called K648 in the globular cluster M15 in Pegasus.  Planetary nebulae are typically only around 10,000 years old and only four such nebulae are known to exist in globular clusters. The remaining mass of K648 is about 60 percent of the Sun, barely enough to create a nebula, but much greater than most stars in the cluster.  To find out why it has more mass, Hubble scientists used the orbiting observatory to look for a nearby star that could have donated a significant amount of mass.  Presently, there is no known companion to this star, but astronomers believe in the past this star formed by the merger of two stars.
 

DUSTY IMPRINTS REVEAL PLANETS

NASA astronomers have studied the patterns imprinted on the dust disks around three well known nearby stars to determine whether a planet is hiding there. The planet is still hidden, but it writes its signature in the dust.  The researchers estimate Beta Pictoris has a planet 10 times the mass of Earth orbiting about 6.5 billion miles from the star, while Epsilon Eridani has a 0.2 Jupiter-mass planet about 5.5 billion miles away, and Vega has a planet twice the mass of Jupiter in an orbit about 5 billion miles away. These distances from the parent star are larger than any of the planets in our solar system.
 

NEW METHOD WILL DETECT EARTH SIZED PLANETS

The University of Arizona has been testing a technique known as "nulling" which they hope will enable them to discover Earth-sized planets orbiting other stars.  A star is ten million times brighter than an orbiting planet and that makes planet detection difficult. Nulling causes the light waves from the star to interfere with themselves, making the star nearly invisible while radiation from the planet comes through. It is possible either to make direct images of a planetary system with this technique or to reconstruct an image by mathematical data processing.
 

GALAXIES FORMED MUCH EARLIER

Astronomers at Durham University have identified many galaxies with redshifts between 4 and 6. This means they were already in existence about 10 billion years ago, when the Universe was six times smaller than it is now. With this discovery, researchers may have to rethink their ideas about how galaxies formed. New infra-red pictures have been taken of small areas of the sky already targeted by the deepest ultraviolet and blue surveys which show such large numbers of galaxies that there seems to be almost as many bright galaxies with redshifts of 5 as there are at low redshifts nearby! This makes the epoch of galaxy formation earlier in the history of the Universe than astronomers previously thought.
 

CHANDRA OBSERVES ANTENNAE

The Antennae Galaxies (NGC 4038 and NGC 4039) which lie 50 million light-years away in the constellation of Corvus, are two colliding and visually stunning galaxies.  Earlier data from the Rosat X-ray observatory showed extended patches of X-ray light in the Antennae, thought to be caused by superbubbles of hot gas surrounding supernovae explosions. Thanks to observations with the Chandra X-ray telescope scientists have found that in addition to the superbubbles, the Antennae contain dozens of bright point-like sources, neutron stars and black holes-- left behind by the flurry of supernova activity.  The X-rays from these sources are generated by gas that is heated to tens of millions of degrees Celsius as it streams from nearby companion stars onto neutron stars or into black holes.
 

WOBBLING PULSAR

Jodrell Bank scientists have been studying 13 years' worth of data from the pulsar PSR B1828-11 which rotates 2.5 times per second and have found that it wobbles regularly with a period of about 1000 days.  This wobble, or precession, has two manifestations: it causes the observed pulse to change its shape, and causes the time between pulses to vary, becoming sometimes shorter,sometimes longer.  Astronomers argue these variations imply that the neutron star, instead of being perfectly spherical, is slightly squashed.  Astronomers know from other long-term observations, mostly done at Jodrell Bank, that a pulsar is made up largely of a neutron superfluid, with a solid crust. Current theories predict that the interaction between the superfluid and the crust should cause any precession to die out extremely quickly.  But this pulsar is one hundred thousand years old, and it's still wobbling!  Jodrell Bank claims that it is remarkable that by observing emission received from these objects thousands of light years away, radio astronomers can study the internal
structure of these tiny objects and learn about the fundamental physics of matter at pressures and densities far greater than anything that can be achieved in a laboratory on Earth.
 

MOST DISTANT NOVAE

Astronomers using the European Southern Observatory Very Large Telescope(VLT) have witnessed the most distant nova outbursts ever seen. They were in the galaxy NGC1316 which lies about 70 million light years away and are the result of binary systems in which one relatively cool star loses matter to its smaller and hotter companion.  No fewer than four novae were detected in the giant galaxy within only 11 days. This implies a rate of approximately 100 novae/year or about 3 times larger than the rate estimated for the Milky Way galaxy.
 

PLUTOEXPRESS MAY BE CANCELLED

Soaring budgets, a scarcity of radioactive fuel and the lack of a tried-and-true launch vehicle may force NASA to scratch plans for a mission to Pluto, the last unvisited planet in our solar system.  Although NASA has not made a decision - nor might it until its 2002 budget proposal comes due in February - the prospect has shaken mission members and prompted one space exploration advocacy group to undertake a letter-writing campaign.  "Candidly, I think there is a very good chance the Pluto mission could be cancelled, but that decision has not yet been taken," said Michael Drake, chairman of NASA's solar system exploration subcommittee.  Preliminary plans call for the Pluto-Kuiper Express to launch in 2004 at the earliest, arriving at tiny Pluto some time between 2012 and 2016. The spacecraft could then venture on to probe one or more asteroid-sized objects in the Kuiper Belt.
 

TAU NEUTRINO - FIRST DIRECT EVIDENCE

Confirmation that the tau neutrino actually does exist has been provided by Japanese Scientists.  An experiment conducted at Fermilab in 1997 left tell-tale trails in layers of photographic-like emulsion which have been carefully examined for the past three years.  Out of around a thousand candidates, just four turned out to be the trails of tau neutrinos.  This finding completes all the matter particles predicted by the standard model of particle physics.
 

NEUTRINOS TRANSFORM

New research by Japanese physicists at the KEK particle physics laboratory has shown that neutrinos oscillate into flavours which are invisible to underground detectors.  Neutrinos come in three flavours: electron neutrinos, muon neutrinos and tau neutrinos (see above story).  The idea of neutrino oscillation began when physicists noticed a difference in the ratio between muon and electron neutrinos that come from the atmosphere and those that pass through the Earth from the far side.  To confirm that they were seeing oscillating neutrinos, researchers at KEK aimed a beam of muon neutrinos at the Super-Kamiokande neutrino detector .  The year-long experiment should have counted 40 muon neutrinos, but it actually only detected 27.  If correct, the experiment has profound implications, because theorists say that if neutrinos oscillate, they must have mass. It would also explain why we only see a third of the neutrinos that emanate from the Sun and significantly contribute to "Dark Matter".
 

AGE OF THE UNIVERSE

Astronomers from Britain, Israel and America have brought together five different kinds of observations: the numbers of clusters of galaxies, the positions and distances of galaxies, ripples in the afterglow of the Big Bang, supernovae in distant galaxies, and flow-like motion of galaxies through space caused by the clumpiness of the Universe.  Checking how far these five different approaches agree with each other, they find good agreement between the first four. Combined together, they give the age of the Universe as 14 billion years plus or minus 2 billion years which is reassuringly older than the estimated ages of the oldest stars in our Galaxy. Taking the last three types of observation together, there is still quite good agreement, but the age of the Universe comes out as 13 billion years plus or minus 2 billion years. The team says there is more work to be done to understand why the results from counting numbers of clusters of galaxies do not quite agree with those from the flows of galaxies.
 

JAPAN'S X-RAY SATELLITE IN TROUBLE

The recent spate of solar storms has seriously affected Japan's ASCA X-ray observatory which is now spinning out of control as it circles the Earth. The satellite lost attitude control and put itself into a state of electronic hibernation sometime on July 15th or 16th.  Astronomers had hoped to get 6 to 9 more months of observations, but the intense solar activity will dramatically shorten that timeline -- assuming the spacecraft can be restored to operation.   The fourth in a series of highly successful Japanese X-ray observatories, ASCA has already exceeded its planned 5-year lifetime.
 

SETI PROJECT BOOST

Two gifts totalling $12.5 million have cleared the way for the development of what is being described as the world's most powerful radio telescope designed specifically to listen for signals that may be coming from civilisations elsewhere in the galaxy.   The SETI Institute of Mountain View, Calif., a private organisation conducting research to determine whether intelligent life exists beyond Earth, has announced that the money would be used to begin work on a proof-of-concept version of the telescope. Under current plans, the telescope, a cluster of many 12-foot dish receivers, would be ready for full operation in 2005.   The principal gift, of $11.5 million, came from Paul G. Allen, a Seattle investor, one of the founders of Microsoft and a philanthropist of scientific research. The project is being renamed the Allen Telescope Array. Astronomers said the Allen Telescope should enable them to examine up to a dozen target stars simultaneously in the search for extra-terrestrial intelligence and to detect signals over an extremely wide range of frequencies.
 
 
 

Bulletin compiled by Clive Down

Reproduced with permission from:
Electronic News Bulletin
Issue No 55,   Aug 2000.

The Society for Popular Astronomy
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  Contents

l'Astronomia d'Italia - Isola d'Elba 2000

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At the end of July we were off to sunny Elba for our summer holiday. At latitude 43 degrees North, there was every prospect of seeing almost the entire constellation of Scorpius and a good portion of the centre of the Milky Way in Sagittarius. I arrived equipped with my Meade ETX90EC and field tripod, a pair of Zeiss 10 x 50 binoculars, my trusty 'Scotch' mount and 35mm camera, and plenty of film (Kodak Elitechrome 400) in readiness for two weeks of clear skies.

 Alas, I was disappointed to find, when we arrived at Villa Morcone, the view to the South was partly obscured by tall trees which had been allowed to grow wildly, obscuring not only the view of the beach, but also about 20 degrees of sky. The view to the west was even worse; a small hill completely ruled out any chance of seeing Venus, close to a young crescent Moon after sunset on the 31st. And forget any possibility of finding comet Linear in Leo. Worse still, the view to the south-east was badly light-polluted by the terrace lights of the surrounding appartments - fine for sitting around tables drinking wine and enjoying the night-life, but very annoying to those of us hoping for a clear view of the heavens. I estimated the limiting visual magnitude at about 4.0; not much better than a good night in Manchester (if there is such a thing.)

 On the positive side, the ETX performed extremely well. After being fed the latitude and longitude (and time- zone) of Elba and once aligned on Polaris, which fortunately was visible above the roof of our 'villa', it was able to locate all the objects requested to within half a degree, so that they appeared within the 1 degree field-of-view offered by the 26mm Super Plossl eyepiece, which comes as standard. Only a small amount of user control was needed to centre the objects, and the tracking in alt-azimuth mode was acceptable, at least for visual observations.

 I was able to view several Messier objects including M16 ( Eagle nebula ), M17 ( Omega ), M8 ( Lagoon ) and M20 ( Trifid nebula ) as well as  the 'Wild Duck' cluster (M11) and the large globular cluster M4, near the red M-class supergiant Antares. The ETX was able to slew within a few seconds to each of these objects in turn, and to do so repeatedly. I did however make extensive use of the synchronise feature, obtained by holding down the ENTER key for a couple of seconds, centering the object and pressing ENTER once more. This had the effect of 'fine-tuning' the Meade's ability to relocate the same object later on.

 I was pleased to be able to locate the planets Uranus (mag. 5.7 ) and Neptune (mag. 7.8 ) both in binoculars and in the ETX, although I had to double check using the Sky Map Pro software on my laptop to ensure that I had correctly identified the two planets. I must say  I was disappointed that Uranus did not really appear to be bluish in the Meade - maybe it is just my poor eyesight, or perhaps a larger aperture is needed to gather more light to stimulate those sleepy cone cells. Of course, it could also be something to do with all the wine we had to drink during the day.

 On a negative note, I cannot say that the skies from the beautiful island of Elba are particularly dark. I had noticed during a previous visit that there are many aircraft passing overhead, on their way to and from Rome. Also, the many holiday homes and camp sites contribute to the light pollution which we are campaigning against in our country; it is an international problem which appears to have no immediate prospect of improvement. Finally, it seems to be a local tradition for the night clubs to advertise their presence in the night sky by means of laser beams and searchlights, which seems particularly pointless unless they are expecting their customers to arrive by air !

 Nevertheless, it was an enjoyable two weeks, more so because of other activities, including my first attempt at SCUBA diving, and collecting samples of the various rocks and minerals which lie scattered around the cliffs and beaches of this amazing little island, known by its residents as 'un giardino nel azzurro'  -  a garden in the blue.

  

John Thomson

Astrophysics at University                by Megan Argo

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 Greetings from Manchester University!  I thought some of you might like to hear what I've been up to in the last few months (and besides, this is much more fun than doing lab reports!).

 The course I'm doing is titled Physics with Astrophysics, but the first year is mainly general physics and some mathematics.  What little astrophysics we have done so far has mostly been covered in lectures at the societies meetings (and some A-level stuff).  For example, the module titled Introductory Astronomy  described the layout of the solar system, the basic properties and classification of stars, the constituents and simple dynamics of the galaxy, the classification of galaxies, a brief introduction to the bizarre world of active galactic nuclei, and some cosmology.  Any of these topics may be familiar to anyone who regularly attends the society meetings.

 There are not many opportunities for actual observational astronomy which is not that surprising for a University department based in near enough a city centre, let alone Manchester where summer just means the clouds are a lighter shade of grey!  Having said that, there is a small optical observatory and ccd camera on the roof of the department but, as you can imagine, there is not really that much to see unless you use a filter.  There is also a 7 metre radio telescope at Jodrell Bank that is for undergraduate use - it is the smallest one you can see off to the left if you look down the road past the planetarium and the research buildings.  Unfortunately though, neither of these telescopes are available for use until the third year and only then as part of a laboratory experiment.  Roll on the third year!!!

 There are about 150 physics students in the first year, about 40 of those are on my course but there are usually more than that in the lectures for the astrophysics modules because they are quite popular with students on other physics courses.  In other first year modules we covered topics such as dynamics, relativity, electronics, data analysis, electricity and magnetism,  thermal physics, and vector calculus!  In general it is interesting but some modules are worse than others mentioning no names *cough*-dynamics-*cough*.

 I've joined the nearest thing to an astronomical society there is at the students union - ManSEDS.  "What is that" I hear you cry, well it is the branch of UKSEDS which is based at Manchester University.  So what is UKSEDS?  It stands for UK Students for the Exploration and Development of Space.  It is a branch of the (originally American but now international) organisation SEDS.  Yet more acronyms, but I bet you can guess what that one stands for!  It is an independent, student-based organisation which promotes the exploration and development of space.    Despite its name, SEDS is not an exclusively student organisation - anyone with an interest can join.

 Once a year, UKSEDS holds a national conference which provides an opportunity for members and other interested types across the country to meet up, listen to talks by people in the space industry, from engineers to astronauts, and find out a bit about the kind of careers available to them. Last years conference was held in Canterbury at the University of Kent on the 20th to the 21st of November and was sponsored by PPARC and Matra Marconi Space UK Ltd.

 The title for the conference was "Life in Space" and included talks by Professor Heinz Wolf, Tim Furniss, Colin Ledsome and people from the Mars Society and AspireSpace.  The highlight of the conference however, was a talk by the British born astronaut in training, Nicholas Patrick Ph.D. who was flown over from America especially for the conference. The talk he gave was absolutely riveting with some beautiful slides, the question and answer session afterwards went on far longer than anyone had planned (but nobody complained!) and it was great to hear an insiders view of NASA's astronaut training program.

 There was a careers fair with stands from Matra Marconi, DERA and Science Systems and on the sunday there was a rocket workshop where young children could assemble, decorate and then launch their own small rocket up to a couple of hundred feet.

[Warning, plug coming up!]

The UKSEDS 2000 conference will be held at Manchester University this November.
The UKSEDS website is at http://www.uk.seds.org/

For more information write to:

 UKSEDS, c/o SET
 Royal Aeronautical Society
 4 Hamilton Place
 London
 W1V 0BQ

 I've been having more fun recently as part of a team of students from the University of Manchester and UMIST who are building a rocket!  This is great because we actually get to do something practical with our knowledge and skills, and we have complete control over the project unlike a laboratory project where you have to follow a script.  In theory, it should reach a height of about a kilometre and send us back some scientific data from the sensors we have assembled for the payload.  Hopefully the launch (and safe landing) will be in September, more details nearer the time!

Fast moving bright asteroid Special Alert

Minor Planet AstroAlert: 2000 QW7

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On August 26, 2000, the NEAT/ MSSS survey (Eleanor F. Helin and colleagues) picked up an unusually bright near-Earth asteroid with its 1.2-m reflector on Haleakala, Hawaii. In an electronic circular issued this afternoon, Gareth V. Williams of the Minor Planet Center http://cfa-www.harvard.edu/iau/mpc.html ) in Cambridge, Massachusetts, designated this object 2000 QW7.

About magnitude 13.6 when first detected, the asteroid will brighten to 12.7 within the next week as it makes a moderately close flyby, coming within 0.032 astronomical unit of Earth (about 12 Earth-Moon distances) in the first few days of September. Anyone with an 8-inch or larger telescope and clear, dark skies should have no trouble spotting the object visually during this period as it glides from Aquarius through Pisces into Cetus. Small CCD-equipped telescopes can also capture trailed images of 2000 QW7. (See the detailed ephemeris at the end of this AstroAlert.)

As soon as NEAT astronomers reported the object, the Minor Planet Center posted the position and direction of motion on the NEO Confirmation Page of its Web site. Within the next 30 hours, a total of 115 precise positions had arrived from 19 astrometric observatories around the world (including 7 positions obtained by the undersigned at the Drum Hill Station in northern Massachusetts). Williams then issued on Minor Planet Electronic Circular 2000-Q32, containing the following preliminary orbital elements (equinox 2000.0):

  Epoch                              2000 Aug. 24.0 TT
  Mean anomaly, M            353.92092
  Semimajor axis, a             1.9510626
  Eccentricity, e                  0.4694395
  Arg. of perihelion             190.39996
  Long. of ascending node  158.81329
  Inclination, I                     4.16947

The elements show that this asteroid belongs to the Amor family and follows an orbit inclined 4.2 degrees to the ecliptic. It ranges as far out as the main belt of asteroids (roughly midway between Mars and Jupiter), but every 2.7 years it comes in to a point fairly close to the Earth's orbit. As far as is currently known, the object has not been detected by astronomers before. Its brightness suggests it may be about a half mile (0.8 kilometer)across.

The following ephemeris, calculated at Sky & Telescope from the above elements, gives the object's right ascension and declination at 6-hour intervals for the next two weeks. Also listed is its distance from the Earth (Delta) and the Sun (r) in a.u., expected visual magnitude, and the constellation through which it is passing.

When searching for the asteroid, keep in mind the parallax effect. Because the object is so close to the Earth in the next few days, it can appear displaced up to about 5 arcminutes from the geocentric positions tabulated below.

Roger W. Sinnott
Associate Editor / Sky & Telescope
 

 Contents
 

Sky Diary

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September - October 2000

New Moon : 27th Sept. & 27th Oct.

The Square of Pegasus dominates the night sky in September - its four bright stars are: Markab (), Scheat (), Algenib ( ) and Alpheratz, which actually belongs to the adjoining constellation of Andromeda and is designated as  -Andromedae. They are all second magnitude stars, but Scheat is an M-class variable, ranging from mag. 2.3 to 2.9 with a semi-regular period of around 38 days - no two cycles are identical. 51-Pegasi is a 5th. magnitude star just outside the square roughly half-way between Alpha and Beta - it is a G3 type, similar to our Sun. In October 1995, 51-Peg. made the headlines as the first star around which a planet, with a mass about half that of Jupiter, had been detected.

Andromeda contains the famous Andromeda Galaxy (M31), located at the end of the line of stars formed by ,  and . To see it with the naked eye requires a clear dark night but binoculars reveal a ghostly patch of light - some claim to be able to make out its orientation. A small telescope will show its companion galaxies, M32 and NGC 205. M31 is the closest galaxy to our own Milky Way at a distance of  some 2.2 million light years. It is actually approaching our galaxy at a speed of 275 km/sec. A billion years from now, any life-forms in either galaxy will have a superb view of the other as they pass through each other in a blaze of star-formation.

Planets on view include the brilliant pairing of Jupiter and Saturn in Taurus, rising in the early evening and reaching the zenith in the wee small hours. Jupiter ( mag. - 2.5 ) is 5 degrees north of Aldebaran (mag 0.99) on the 7th. Saturn, which rises before Jupiter, is magnitude +0.3 at present but brightening gradually as it approaches opposition on November 19th. when it will reach mag. -0.2. Jupiter is at opposition on Nov. 28th. (mag. - 2.8). Mars ( mag. 1.8) is too close to the Sun to be viewed until October, early in the morning. Venus is mag. -3.8, but very low in the western sky at sunset. Like Mercury, it is best viewed in daylight using a telescope with 'go-to' function, or by means of accurate setting circles, but extreme care must be taken not to view the Sun directly! A better view of Venus will be had in October as its phase decreases and its angle from the Sun decreases, becoming a brilliant evening star of  mag. - 4.1 by Christmas.
 
 

Contact the Editor !

Comments and articles should be sent to: J H Thomson by e-mail at,       jhandlc@thomson.u-net.com
or in-person at any of our monthly meetings, or to any member of the committee.

The contents of this Journal are best viewed 'on-line' at our web-site address - http://www.g0-evp.demon.co.uk/main.html