*********************************** The SOCIETY for POPULAR ASTRONOMY *********************************** ==================================================== Electronic News Bulletin No. 288 2010 May 16 ==================================================== Here is the latest round-up of news from the Society for Popular Astronomy. The SPA is Britain's liveliest astronomical society, with members all over the world. We accept subscription payments online at our secure site and can take credit and debit cards. You can join or renew via a secure server or just see how much we have to offer by visiting http://www.popastro.com/ Astronomica is sponsoring the SPA Electronic News Bulletin. LYRIDS By Alastair McBeath, SPA Meteor Section Director As discussed in ENB 286 (archived at: http://snipurl.com/w9p9b ), the Lyrid maximum was due on April 22 this year, sometime between 09h-21h UT. Indications are the highest Zenithal Hourly Rate (ZHR) reached ~20 +/- 4, so roughly normal, around 17:00-21:30 UT that evening, judging by the International Meteor Organization's (IMO's) "live" Lyrids page, at: http://www.imo.net/live/lyrids2010/ , detected despite the late-setting waxing gibbous Moon (which set only after the start of morning twilight for much of Britain). Disappointingly few people were able to report-in positively from the shower to the SPA. British sky conditions seem to have been their usual frustrating mixture, and things elsewhere were not ideal. There are some notes on how some people fared in parts of Britain on the UK Weather World's Space Weather Forum for example, at: http://snipurl.com/wa0tw . The IMO-reported maximum's timing was very poor for Europe and North America, from where most SPA contributors typically observe. European observations reaching the Section directly, including those from the UK, suggested activity around 00h-03h UT on April 21-22 was around 10 +/- 3, perhaps a little higher towards dawn. Although based on very few results, this was in-line with the IMO's preliminary findings. Examining the data in Radio Meteor Observation Bulletin 201 (for April 2010; see: http://www.rmob.org ) showed little clear sign of the Lyrids this time, hardly surprising for the European systems especially, given that the shower's radiant was about at its lowest elevation for the day, or indeed below the horizon for some, during the probable peak. Western North American observers had somewhat better conditions initially then, but with a declining to setting radiant generally. However, a majority of North American systems did find distinctly elevated echo counts from roughly 12h-15h UT, plus-or-minus an hour at either end of this interval, likely part of the rising activity towards the Lyrid maximum. One or two European systems suggested modestly enhanced activity above normal from about 04h-10h UT that day, which was perhaps still present through to around 04h-05h UT on April 23, though this was inconclusive as so few systems detected it. One far-west North American set-up recorded a notably stronger peak from 18h-20h UT on the 22nd, nicely in-time to the visual findings at least, if again unconfirmed elsewhere. Our contributing observers active over the Lyrid epoch were as follows, including information from the North American Meteor Network (NAMN; see http://www.namnmeteors.org ), kindly provided by Network leader Mark Davis, and RMOB 201 helpfully submitted by editor Chris Steyaert. In the list, "R" means radio and "V" visual results came from that individual: Salvador Aguirre (Mexico; NAMN; V), Enric Algeciras (Spain; RMOB; R), Orlando Benitez (Canary Islands; RMOB; R), Michael Boschat (Nova Scotia, Canada; RMOB; R), Jeff Brower (British Columbia, Canada; R; some data also in RMOB), Willy Camps (Belgium; RMOB; R), Johan Coussens (Belgium; RMOB; R), Gaspard De Wilde (Belgium; RMOB; R), John Drummond (New Zealand; NAMN; V), Franky Dubois (Belgium; RMOB; R), David Entwistle (England; RMOB; R), Kurt Fisher (Utah, USA; RMOB; R), Karl-Heinz Gansel (Germany; RMOB; R), Dave Hancox (Scotland; V), Ken Hodonsky (Illinois, USA; NAMN; V), Conor McDonald (Northern Ireland; V), Mike Otte (Illinois, USA; RMOB; R), J|rgen Rendtel (Germany; V), Steve Roush (Arizona, USA; RMOB; R), Wayne Sanders (British Columbia, Canada; RMOB; R), Andy Smith (England; RMOB; R), Chris Steyaert (Belgium; RMOB; R), Dave Swan (England; RMOB; R), Rich Taibi (Maryland, USA; V), Istvan Tepliczky (Hungary; RMOB; R), Felix Verbelen (Belgium; RMOB; R). Many thanks go to everyone involved for their efforts, and commiserations to those who were unlucky with the weather. Any additional Lyrid results would be most welcome! APRIL FIREBALLS UPDATE By Alastair McBeath, SPA Meteor Section Director As regular followers of the Section's webpages may be aware, there have been problems and delays in updating the "Recent Fireball Sightings" page in recent weeks (at: http://snipurl.com/w9p6d ). The notes here summarize the fresh information received on already-reported British fireballs, and new events, since ENB 287. A third observation of the magnitude -10 or so fireball at 20:15 +/- 5 minutes UT on April 9-10 has arrived, from the western Highlands of Scotland. The estimated possible overflight zone for the object is still as reported in ENB 287, however. Several additional sightings have come in from April 16-17, but not all were of the very bright, green fireball seen near 22:00 UT. New sightings of that meteor have arrived from Kent and western France, bringing the total to six, although without refining the possible area of its occurrence as yet. The extra events included: a magnitude -5 meteor seen to the northwest, heading north from Kent, at some time probably between 21:30-21:45 UT; another bright green meteor, which was also close to 22:00 UT, but observed to the east-southeast from Norfolk, meaning it must have been a different meteor to the multiple-observer event near the same time; and a third bright green fireball near 23:55 UT, as spotted from Hertfordshire. Preliminary notes on this latter event can be found on the SPA's Observing Forum topic for the ~22h UT meteor, at: http://snipurl.com/wagm0 . April 17-18 brought another bright, green-white fireball for a lucky witness in Gloucestershire around 23:00 UT, followed by a magnitude -3 meteor at about 22:00 UT on April 23-24, as seen from Suffolk. Notes on this fireball also can be found among the comments regarding the April 16-17 fireballs on the Observing Forum. April 27-28 produced a very bright meteor within ten minutes of 20:15 UT, as witnessed from three sites in southern England - Kent, Wiltshire and Shropshire. The Shropshire observer indicated a probably- associated sonic boom had been heard as well, while the other viewers noted the object had fragmented during its flight. No information regarding its possible trajectory is yet available, but if the sonic boom was linked to the meteor, it may have passed over or near southern Shropshire. More news has come from the USA regarding the April 14 Midwestern fireball as well, commented upon last time. Regular Section contributor and correspondent Jeff Brower in southwestern Canada noted it was featuring almost nightly on the TV news there, and that 2.3 kg of meteorites had been recovered by April 26, the first just a day after the fireball flew over. The timing has been refined to 22:07 local, 03:07 UT, while the observer tally has continued to grow, with the American Meteor Society's fireball webpage (off the http://www.amsmeteors.org homepage ) indicating it was seen from twelve states across the American Midwest and Great Lakes regions. Witnesses in Wisconsin and Iowa heard sonic booms as the object detonated, showering Wisconsin with meteorites in and near the town of Livingston. Numerous additional video recordings have been collected since the ENB 287 notes, many from security cameras, catching the late flight. The meteorites were detected by weather radar during their lower-atmosphere flight too. (Additional notes on this meteor were from the April issue of the IMO's journal WGN, Vol. 38, No. 2, p. 49, in the Editorial by Javor Kac.) Observations of fireballs (meteors of magnitude -3 and brighter) seen from the British Isles and places nearby are always welcomed by the Meteor Section. For advice on what information to send (including an e-mail report form), see the "Making and Reporting Fireball Observations" page of the SPA website, at: http://snipurl.com/u8aer . LUNAR FEATURE OF THE MONTH - MAY 2010 By Peter Grego, SPA Lunar Section Director A mighty cliff: Rupes Recta, the Straight Wall On 21 May the Moons sunrise terminator rolls back to reveal a remarkable feature near the southeastern shore of Mare Nubium (the Sea of Clouds) -- one of the Moons most magnificent cliffs, Rupes Recta, the so-called Straight Wall, a feature caused by crustal faulting. Tension in the Moons crust following the cooling of the lavas which filled Mare Nubium around three billion years ago pulled the crust apart. The crust eventually cracked under such stresses, and the force of gravity produced a horizontal displacement between the two separated blocks of crust, the crust in the west dropping down relative to the eastern side of the fault; the exposed edge is a cliff known as a fault scarp. Rupes Recta is by far the best example of a normal fault on the Moon. The fault scarp has a rather gentle gradient of around seven degrees and runs north south for 126 km from the Stags Horn Mountains to the small crater Birt D, in a very slight curve. The Straight Wall is best seen just after First Quarter phase, as on 21 May, when it throws a prominent broad shadow westward onto the relatively flat mare floor, so bold as to be easily visible through binoculars. The cliffs shadow gradually recedes over the next day or two and is virtually invisible at high illuminations when no shadows are cast. However, around Last Quarter phase as the evening terminator approaches Mare Nubium, the cliff face brightens and shows up clearly as a bright narrow line. 35km west of Rupes Recta, and lying parallel to it, is a narrow cleft  a channel carved by running lava -- known as Rima Birt which connects the small craters Birt E and Birt F. An 80mm refractor will just about resolve Rima Birt on a fine night and under favourable conditions of illumination. PLANETS By Andrew Robertson, SPA Planetary Section Director VENUS is now moderately high in the west after the Sun has set. You can't miss this beacon of our skies. A thin crescent Moon joins the scene on Sunday evening. MARS is still a very noticeable red at mag +0.9 on the borders of Cancer & Leo, but at less than 7" diameter little can be seen on its surface, although you may notice its phase of 90% if a high power is used. SATURN is well past opposition now but still fairly high in the south just after sunset. Its rings are at about their narrowest of 2 degrees at present. In subsequent years they will start widening again, so it is worth having a look at in this rare view. It is feasible to see transits of its moons when the rings are close to edge-on. The easiest to see are Titan's but none is visible from the UK this apparition. The next easiest are Rhea, Dione and Tethys, but you will need a moderate to large telescope (preferably optimised for high contrast) and excellent seeing, when you may glimpse a shadow transit. Seeing the actual moons themselves in transit is very doubtful. JUPITER is a morning object, rising just before 3.30am BST, but by the time the Sun has risen (5am) it has only reached an altitude of 15 degrees. However, Jupiter's South Equatorial belt has disappeared, so it has an unfamiliar look about it, so worth trying to get a view if you can. ICE FOUND ON ASTEROID NASA Scientists have detected water-ice and carbon-containing compounds on the surface of an asteroid. A seemingly sweeping generalisation from the discovery of those substances on *one* large asteroid has resulted in a suggestion that some asteroids, along with comets, were the water carriers for the primordial Earth. The discovery is a result of seven observations, the first of which was made in 2002, of asteroid 24 Themis by astronomers who were using an infrared telescope. The findings are surprising because it was believed that Themis, orbiting at 479 million kilometres, was too close to the Sun to carry ice left over from the Solar System's origin 4.6 billion years ago. GALACTIC STAR FORMATION IS SLOWING ESA Astronomers using the Herschel infrared telescope have shown that the formation of new stars in galaxies like the Milky Way has declined fivefold in the last three billion years. Observing in the infrared has allowed scientists to see galaxies, mainly spiral ones like the Milky Way, that were previously hidden from view by cosmic dust clouds. The Herschel telescope, launched a year ago to study star formation, is the biggest ever sent into space, and is orbiting at a distance of 1.5 million kilometres from the Earth. BLACK HOLE THROWN OUT OF GALAXY RAS Astronomers who have been comparing positional catalogues of X-ray sources and of galaxies have found what appears to be a super-massive black hole leaving its home galaxy at high speed. The material that falls into black holes heats up dramatically on its final journey and often causes black holes to be strong X-ray sources. X-rays are also able to penetrate the dust and gas that obscures the centre of a galaxy, giving astronomers a clear view of the region around the black hole, with the bright source appearing as a starlike point. Looking at one galaxy in the catalogue, researchers noticed that the point of light was offset from the centre and yet was so bright that it could well be associated with a super-massive black hole. The black hole appears to be in the process of being expelled from its galaxy at high speed. Since such objects can have masses equivalent to 1 billion Suns, it takes a special set of conditions to cause that to happen. It is being speculated that the newly-discovered object may have resulted from the merger of two smaller black holes. Models suggest that the merged hole that results is shot out at a high speed, that depends on the direction and speed at which the two black holes rotate before their collision. MOST DISTANT CLUSTER OF GALAXIES IPMU, Japan Galaxies seem not to be uniformly distributed in the Universe, but to be arrayed in filamentary structures that form a gigantic cosmic spider web. Clusters of galaxies are often located at knots in the filaments. The most distant cluster known until now is about 9.2 billion light-years away. The expansion of the universe shifts the light of distant objects away from visible wavelengths, towards the infrared. Observing in the infrared may therefore enable astronomers to see more distant objects. On the other hand, clusters of galaxies tend to contain a lot of matter heated to extreme temperatures, at which the emitted light is of such short wavelengths that even despite the redshift it appears as X-rays. A team of astronomers from Japan and Germany has used an infrared camera on the Japanese Subaru telescope in Hawaii to discover the most distant cluster of galaxies observed up to the present, 9.6 billion light-years away. The team also used the orbiting X-ray observatory XMM-Newton, and detected a clear signature of hot gas in the cluster. ENGINEERS WORKING ON VOYAGER 2 DATA SYSTEM ScienceDaily Engineers have shifted the Voyager 2 spacecraft into a mode that transmits only spacecraft health and status data while they try to correct an unexpected change in the pattern of returning data. Preliminary engineering data received on May 1 show that the spacecraft is basically healthy, and that the trouble is with the flight data system, which formats the data to send back to Earth. The first changes in the return of data packets from Voyager 2 appeared on April 22. Engineers got their first chance to send commands to the spacecraft on April 30. It takes nearly 13 hours for signals to reach the spacecraft and the same for signals to come back to the Earth. Voyager 2 was launched on 1977 August 20, about a fortnight before its twin spacecraft, Voyager 1. The two spacecraft are the most distant man-made objects, out at the edge of the heliosphere, the bubble that the Sun creates around the Solar System. Voyager 2 is about 13.8 billion kilometres away, Voyager 1 about 16.9 billion kilometres. Mission managers expect Voyager 1 to leave the Solar System and enter interstellar space in the next five years or so, with Voyager 2 to follow shortly after. Voyager 1 is in good health and performing normally. Voyager 2's initial mission was a four-year journey to Saturn, but as part of a mission extension it also flew past Uranus in 1986 and Neptune in 1989, taking advantage of a once-in-176-years alignment to take a grand tour of the outer planets -- and it is still returning data 33 years after launch. (c) 2010 the Society for Popular Astronomy The Society for Popular Astronomy has been helping beginners to amateur astronomy -- and more experienced observers -- for more than 50 years. If you are not a member then you may be missing something. Membership rates are extremely reasonable, starting at just #16 a year in the UK. You will receive our bright quarterly magazine Popular Astronomy, regular printed News Circulars, help and advice in pursuing your hobby, the chance to hear top astronomers at our regular meetings, and other benefits. 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