Volume XIX No. 10 June 2008 What's Inside… IAU's "Plutoid" Pg 3 Stewart's Skybox Pg 4 Contacts & Schedules Pg 10 Theater in the Sky Pg 11 Science Outreach and Update Pg 12 Note: Use bookmark panel in Adobe Reader. S ome folks may not realize that the Schupmann Medial is the only perfectly achromatic refractor. So much so that the word achromatic doesn't really even properly apply to it. Achromatic as applied to refracting optics simply means that two wavelengths of light (usually the red and blue lines of the hydrogen spectrum) are brought to a common focus. Even an apochromatic lens brings only three wavelengths to a common focus. In the Schupmann Medial telescope, all wavelengths within the entire visible spectrum (and for a good bit outside in either direction) are brought to a common focus. This is achieved by using a single type of glass (preferably from the same melt) for both the positive refracting objective and the negative refracting corrector lenses. In the diagram below, the objective is the large double convex lens at the left, and the corrector is the smaller meniscus lens above the center. The refractive powers of these two lenses are adjusted (by choice of the curvatures) to be equal in magnitude, but opposite in sign. All refraction, including dispersion, is completely cancelled out. The only reason the Schupmann can bring light to a focus at all is that the convex back surface of the corrector is aluminized and it focuses the light like a concave mirror. The perfect cancellation of the refraction and dispersion can only occur when a real image of the objective formed by an intermediate field lens or field mirror is perfectly aligned onto the corrector lens. The field mirror (lower right in the diagram) is tilted up just the right amount to reflect the image of the objective onto the correc-tor. An interesting aspect of this situation is what happens when the real image is not perfectly aligned. That is, point images are spread into spectra exactly as if you had placed an objective prism in front of the telescope objective. This means that not only can you cancel out atmospheric dispersion by careful adjustment of the field mirror, but you can also see the spectra of stars without having a spectroscope at all! I imaged the Trapezium in the Orion Nebula with the field mirror properly aligned and then again after tweak-ing it a bit to form the spectra. Figure 1 is an overlay of these images. Figure 2 is a widened image of the Tra-pezium stars. I may have resolved lines in the visible spectra of the two type B stars (D and B) but not in the type O stars (C and A), which may be just what we should expect. Spectral lines are weak in type O and could be easily obscured by the seeing conditions and insufficient sampling. All of the stars appear to have lines in the near infrared region (appearing orange through grey at the extreme right). Note that the original images were taken at f/14 and I had to use 3x resampling and dithering to bring out the details in these spectra. Some of the dark lines in the spectrum of star D appear to line up with lines in a comparison solar spectrum, but I can't exclude the possibility that these are chance alignments of stretched noise elements. Jim Daley published (on the Yahoo Schupmann discussion group) a spectrum he obtained in this way of kappa Ursae Minoris using his 9-inch Schupmann Medial operating at a focal length of 285 inches under good seeing conditions. See Jim's spectrum in Figure 3 on the next page. He did it by taking a time exposure with the drive turned off causing the spectrum to trail perpendicularly to the dispersion. It shows the whole Balmer series of hydrogen lines from alpha to zeta. Beta is there too, marked F. The big problem with taking useful spectra this way is that the line width (and the resolution of adjacent lines) is determined by the seeing since there is no slit. Jim's seeing in Vermont tends to be considerably better than what we get in New Jersey. Ha(c) means H-alpha which is also known as the C line, "A" and "B" are two different lines of terrestrial at-mospheric oxygen. They occur at 0.759 micron and 0.696 micron wavelength. The latter are red lines and you might be more familiar with them as 7590 angstroms and 6960 angstroms. Ed note: On August 17, 2007, Clif delivered a talk as part of the Fridays At Sperry program titled, "Building the Optical Tube Assembly for a 7.25-Inch Schupmann Medial Refractor. The MacGregor Observatory at Stellafane, Vermont houses a large Schupmann-design telescope. See also "The Schupmann Telescope The Story, Design, Construction and Use of a Neglected Telescope Type" by James Daley from Willmann-Bell. Stewart's Skybox by Stewart Meyers T His month marks a major anniversary in the history of space science, yet it will go largely unheralded. But this, as will be explained later, is due to timing. The anniversary I refer to is the 100th anniversary of the impact at Tunguska, Siberia. This event is the largest confirmed cosmic impact on Earth in recorded human history. Some might argue that a larger impact took place in 535 AD based on a theory by astrophysicist Victor Klube of Oxford University to explain a global environmental catastrophe in that decade, but the events are better explained by a large volcanic eruption in Indonesia that year. Others might bring up a putative impact over Wisconsin and Illinois in October of 1871 that set off a number of intense firestorms, citing a theory put forth by Mel Waskins in 1985. However, the evidence for this is nothing more than anecdotal and circumstantial. But many lines of evidence have confirmed the Tunguska event. June 30, 1908 June 30, 1908 started out like any other June day of that era in the Tunguska River region of Siberia. The local nomads were getting started on another day of following reindeer herds and performing their other ordi-nary activities. Small villages that dotted the region were starting on their morning routine. However, this nor-mal day would change in an instant. At about 7:17am, a bright fireball was spotted in the western sky. It quickly grew brighter and sported a smoke-like trail. Seconds later, it became too bright to look at. Then, there was a powerful explosion and a strong shockwave. At least one entire herd of reindeer was vaporized. Tunguska researcher Yuriy Kandyba found a report of a local man who was hurled by the shockwave into a tree and died of his injuries. Another report told of an elderly villager who died from a heart attack possibly caused by fright from the event. The immediate effects were felt over a very wide area. In the village of Vanovara, at a distance of 60 kilome-ters (37.2 miles) from ground zero, Mr. S.B. Semenov was standing outside the local trading post when the explosion happened. He later reported that he felt a burst of intense heat so strong that he thought he had caught fire and then was knocked to the ground by the shockwave. The shockwave itself was felt, though no-where near full intensity, as far away as the city of Tiflis in what is now the nation of Georgia, 2,727 miles away. While the explosion was over quickly and the resulting forest fires ended within days, other effects of the blast were longer lasting and far reaching. In 1843, the barograph (a barometer that continuously recorded pressure readings on paper) had been invented by Lucien Vidie, and by 1908, weather services in most Euro-pean countries were using them. In the hours after the event, barographs around the world recorded two wave- like pulses in air pressure. It would later be discovered that this was the shockwave of the explosion circling the globe twice. But the shockwave was not limited to the atmosphere. Seismographs as far away as the German city of Jena registered the shock. As night fell in Europe and northern Asia, the sky did not become dark, but resembled twilight. This puzzled most people as news of the impact had not spread much further than Irkutsk, the city nearest to ground zero, by the end of that day. This strange phenomenon was, many years later, found to be due to the dust thrown into the stratosphere as a result of the event, reflecting sunlight. The combination of short summer nights and ice condensing on the dust particles enhanced this effect. By mid-July 1908, fragments of news about the event had reached the outside world. However, there was no immediate investigation. Part of this was due to the remoteness of the area. But the main reason was that the Czarist government of Russia had more pressing concerns than an explosion in a far-off, almost unpopu-lated region. In 1905, there was a failed revolution (this would serve as the setting for the silent film classic "The Battleship Potemkin" which was made in 1925). Preventing future uprisings was considered more impor-tant than were astronomical events. Plus, Russia was getting involved in the web of alliances in Europe that would eventually lead to World War I. But, it might have been the war that eventually got the scientific ball roll-ing on the Tunguska event. Enter the Communist In 1917, as a result of resentment over Czarist rule, losses on the battlefield in World War I, and a little help from the Germans (German agents located Vladimir Lenin and had him sent into Russia for the purposes of stirring up trouble) there were two revolutions. The first initially unseated the Czar and toppled the government. Lenin and his followers felt that the revolution did not go far enough, and they launched the more famous Oc-tober Revolution, which set up communist rule in Russia leading to the formation of the Soviet Union in 1923. In an effort to show that the Communist regime was superior to the old Czarist government, the new gov-ernment took an interest in science. This is where the most famous figure in the history of the Tunguska event enters the story - Leonid Kulik. Kulik was a mineralogist who specialized in meteorites. He realized that the reports of a massive explosion in Siberia might be a cosmic impact, and that it could confirm the then-controversial idea that some craters on Earth had been formed as the result of impacts. The first visit Kulik made to the Tunguska area was in 1921 while he was looking for other meteorites in Siberia. There, he col-lected reports from eyewitnesses. Despite the years since the event, many of the locals remembered the event well, and their recollection of a bright fireball in the sky bolstered Kulik's belief in a cosmic impact. However, Kulik got no closer to the impact zone than the town of Kansk, the railway station nearest to the area. The next trip was in 1927. This time, Kulik visited the impact zone. One of the first things he noticed were the trees. The trees that were alive at the time of the blast had been toppled over and singed. Kulik soon found that the trees seemed to be pointing away from the possible ground zero of the impact. Mapping the area of toppled trees, he found that the area was quite vast and it covered about 1,243 square miles. After forming an idea where ground zero was, Kulik and his men set off for that location. It was not an easy trip as it was Siberian summer with swarms of mosquitoes and muddy marsh-like ground conditions. When the expedition arrived at ground zero, they made a very strange discovery. Instead of the expected impact crater, Kulik discovered a stand of trees. The trees were horribly burned, but they were not toppled over like those in the surrounding forest. Naturally, the scientists were totally perplexed. One way around the lack of a central crater, Kulik reasoned, was that the meteorite may have broken into a swarm of smaller ones. And some of these might have made pits in the ground. To check out this hunch, Kulik and his men located a few ponds in the area that looked promising, and pumped out the water. After this very laborious exercise, the expedition came up empty. Frustrated, Kulik and his men returned home. Kulik made one final trip to the region in 1938 and was able to conduct aerial mapping. But, in June of 1941, the Nazis invaded the Soviet Union in Operation Barbarossa and the Soviet Union was officially involved in World War II. Kulik, though he was exempt from military service because of his age and scientific achieve- ments, joined the Moscow People's Militia. Unfortunately, he was captured by the Nazis and he died of typhus in a prison camp in April of 1942. Yet, it was the end of the war that would offer new insight into what hap-pened at Tunguska in 1908. August 1945 In early August of 1945, the Soviet Union declared war on Japan as they had promised at the Yalta Confer-ence. They soon were advancing rapidly against Japanese positions in Manchuria. Remembering how Ger-many had been partitioned at the end of the European part of the war, the Americans wanted to end the war before the Soviets could even begin to launch their invasion of Japan. On August 6th, 1945, the B-29 bomber Enola Gay left the airfield on Tinian and dropped an atomic bomb on the city of Hiroshima. This was followed on August 9th when the B-29 Bock's Car dropped a slightly more pow-erful atomic bomb on Nagasaki. This had the effect of convincing the Japanese government to surrender. As soon as the war was over, scientists visited the ruins of Hiroshima to learn about the effects of the bomb. One of the first things they did was collect reports from the survivors. These bore considerable similarities to the reports from Tunguska. There were accounts of intense heat and a violent shockwave. A final eerie similar-ity with the Tunguska event was located at ground zero. The Hiroshima Prefectural Industrial Promotion Hall, like the stand of trees at ground zero in Tunguska, was still standing, though it was a burnt ruin. The building was never demolished, nor was it restored, and it was left to serve as the Hiroshima Peace Memorial. The similarities were not coincidental. The Hiroshima bomb and the Tunguska explosion were both airbursts at some altitude above the ground. In fact, the explosions of large conventional bombs, large caliber artillery shells, nuclear weapons, and cosmic impacts follow the same physics. The Usual (and Unusual) Suspects After World War II, scientists started to regain their interest in the Tunguska explosion, no doubt aided by in-sights into high-energy explosions derived from nuclear weapons research. In the 1950s, a team of Soviet nu-clear scientists, armed with little more than slide rules, logarithm tables, data from nuclear tests, and Kulik's reports, analyzed the Tunguska event. They concluded that yield of the explosion was between 10 and 15 megatons and it took place at an altitude of about five miles. Interestingly enough, in the 1980s, a team of American scientists using a supercomputer model designed to simulate nuclear explosions arrived at the exact same result. Attention was also turned to what could have caused the explosion. Unfortunately, a Russian science fiction author inadvertently led many gullible people down a false path. In 1946, Alexander Kazantsev wrote a short story about an alien spacecraft on a trip to Earth. While on its way to study Lake Baikal, the ship's reactor went critical, and it exploded over Tunguska. There is no evidence that the story was meant as anything other sim-ple entertainment, but lots of people took the idea of an alien ship explosion and ran with it. Sadly, this false view still has a few believers to this day. Of course, the alien spacecraft accident wasn't the only outlandish theory about the explosion. Another one, favored by some conspiracy theorists, is that one of those secret organizations bent on world domination con-ducted secret nuclear research in the early 20th century, and that the Tunguska explosion was their test blast. These theories got a little boost when some surveys in the 1950s detected tiny amounts of radiation in the impact zone. However, this radiation had a rather mundane origin, as it was the result of fallout from the earlier above ground nuclear tests of the Soviet nuclear weapons program. Aliens and secret organizations weren't the only odd theories put forth to explain the explosion. One candi-date idea was that a chunk of antimatter fell to Earth, which was proposed in 1965 by Clyde Cowan, C.R. At-luri, and W.F. Libby. However this suffers from the problem that there is no significant quantity of antimatter anywhere in the solar system. Even if there were, it would most likely be annihilated by interaction with matter contained in the solar wind before it got anywhere near Earth. A slightly more plausible candidate is a collision with a miniature black hole, an idea suggested by J.J. Jack-son and Michael P. Ryan in 1973. These hypothetical objects were thought to have formed shortly after the Big Bang and would pack the mass of a typical asteroid. According to this theory, the colliding black hole would slam into the Earth with enough force to create the effects at Tunguska and pass right through to the other side and continue on its way. However, there is no record of any odd happenings on the side of the globe opposite from Siberia. An analysis of the old 1908 barograph records done in 1974 by William Beasley and Brian Tinsley from the University of Texas found no evidence of any shockwaves originating from the point in the South Atlantic that was on the other side of the globe from Tunguska. Also, the existence of miniature black holes is considered somewhat unlikely as any such objects would have disappeared by now due to the effects of Hawking radiation (Hawking radiation is a process where virtual particle formation near the event horizon of a black hole can rob it of energy - the effect is far more efficient with smaller black holes than with larger ones). With the oddball theories disposed of, what remains are the possible causes that Kulik and his contemporar-ies considered - comets and asteroids. Each theory has its strengths and weaknesses, but none is implausi-ble. Morning of the Comet In this theory, initially put forth by no less a figure than the late Fred Whipple and independently by Soviet astronomer I.S. Apatovich, it is thought that the object was a chunk (about 100 meters across) of a comet nu-cleus (Czech astronomer Lubor Kresak believed it might have been from Encke's comet). Up until recently, it was thought that comet nuclei were chunks of frozen gases, ice, and dust with rocky cores. Such a composi-tion could cause the havoc witnessed at Tunguska. But this was before the study of the Comet Shoemaker-Levy 9 fragments in 1994 as well as the Deep Impact mission in 2005. Our new understanding of comets shows that their nuclei are dust-ice mixtures of relatively low density. An object of low density would not likely survive very long if it entered our atmosphere and it would probably explode at an extremely high altitude with little or no effect on the ground. This is borne out by the high altitude explosions detected almost monthly by military surveillance satellites. While not a fatal weakness, some versions of the comet theory depend on something known as the "Canter-bury Swarm", a collection of large pieces of cometary debris in an orbit that brings it near the Earth from time to time. The name comes from a sighting made by Gervais of Canterbury, a monk, in 1178 that has been inter-preted as the impact that formed the lunar crater Giordano Bruno. It has been thought that a large chunk in this swarm caused the impact. However a recent computer simulation of the lunar cratering process has shown that such an impact would have resulted in a weeklong meteor storm on Earth as some of the impact debris escaped the Moon and fell to Earth. This did not happen in 1178. So, the evidence for the Canterbury Swarm is limited to a few impacts on the Moon detected by the seismometers left by the Apollo missions and that could be mere coincidence. Also, an analysis of all available information on the event by Zdenek Sekanina in 1983 severely weakens the case for a comet fragment. In addition to the objections mentioned above, Sekanina pointed out that the esti-mated orbit of the impactor prior to colliding with Earth was inconsistent with that of a comet. Still the comet theory does account nicely for the apparent lack of a crater at the impact site as well as the absence of any conspicuous impactor debris. But it is not the only possible answer. Getting Stoned Another possible explanation involves a small asteroid. This is what Kulik initially suspected, though he be-lieved it was a standard nickel-iron one that would have left a huge crater, but that is not the case. But not all asteroids are created equal. Some kinds might be too fragile to make it all the way to the ground. One such kind would be a carbonaceous chondrite. These are composed mostly of carbon compounds and are rather crumbly. These meteorites weather quite quickly, so any bits that survived the explosion would probably have eroded beyond recognition by the time Kulik reached the area in 1927. Another possible candidate would a stony asteroid. This is the theory Sekanina arrived at in 1983. While denser and having a much more substantial composition than the carbonaceous chondrites, these could explode from the stresses endured during the fiery descent into our atmosphere. Naturally, one of these would explode at a much lower altitude than a comet nucleus, hence increasing the likelihood of damage on the ground. Since these meteorites are made of stone, one might think that some chunks could actually reach the ground and be found by a meteorite expert like Leonid Kulik or the trained geologists of later expeditions. However, there are two ways around this. One is that the object exploded with sufficient force that its entire surviving mass was turned to dust that would not have been noticed by Kulik's expeditions. This has support from analysis of fireballs tracked by automated camera networks in the 1960s as well as from computer model-ing based on the properties of known stony meteorites. Or it is possible that some chunks did make it to the ground, but due to the fact that the ground in that area turns a bit swampy every summer, the chunks might have simply sunk out of sight between 1908 and 1927. Bits in Trees Discovery of any debris from the impactor could go a long way towards resolving what kind of object it was. One promising idea was to search trees that were alive at the time for any particles that might have gotten shot into the tree by the shockwave. When this was done by some Soviet expeditions in the 1960s, there was some good news and some bad news. The good news was that particles were found and the presence of elements such as iridium confirmed an extraterrestrial origin. The bad news was that they were condensed droplets of molten debris that lacked lighter elements, thus there was no conclusive evidence to choose between the two possibilities. Soil samples from the impact zone as well as Antarctic ice cores (from a depth corresponding to ice that formed in 1908) studied by Ramachandran Ganapathy in the 1980s showed similar results. Kulik Avenged? It seems that Kulik's hunch that a Tunguska crater does exist, but is hidden might have been proven right af-ter all. In 2007, an Italian expedition led by Luca Gasperini of the University of Bologna (http://www-th.bo.infn.it/tunguska/?) studied Lake Cheko, about five miles from ground zero. Using sonar, it was discovered that the lake bottom had a conical shape, as opposed to the more irregular shape of other lakes in the region. The sonar also revealed the presence of an object beneath a layer of sediment. If this is indeed a crater and the object turns out to be a piece of the impactor, then the mystery will be solved. As of this writing, the true nature of Lake Cheko is still being debated. Gasperini's expedition is planning another trip to the lake this summer in an effort to drill down to the mystery object. The Incredible Shrinking Impactor It seems that the explosive yield of the Tunguska blast has been overestimated for many years. The reason turned out to be simple. All simulations and mathematical models had treated the event like a nuclear airburst and they totally neglected the effect of downward velocity on the shockwave. Omitting this in nuclear weapon calculations is understandable as the speed of even an incoming ICBM warhead at time of detonation is quite slow compared to an incoming cosmic impactor. When Mark Boslough of Sandia Labs (http://www.sandia.gov/news/resources/releases/2007/asteroid.html) incorporated the downward velocity of the impactor at time of detonation, the yield of Tunguska dropped to about three megatons. The increased velocity of the shockwave compensated for the weaker explosion. However, this still does not change the debate about the nature of the impactor itself. A Matter of Timing You might be wondering why the centennial of this event is going to receive so little press. As I mentioned earlier, the main reason is timing. As almost everyone knows, the Earth rotates on its axis once each day or about 15 degrees an hour. When the impactor reached Earth, the luck of the rotational draw had the Tunguska river area in Siberia in the crosshairs. As a result, the impact took place in a remote, sparsely populated region with almost no human casualties, thus history remembers it only as an odd event. It could have been very dif-ferent. Suppose the impactor reached Earth five hours later. Instead of Siberian forest and swamp, the city of St. Petersburg would have been the target. St. Petersburg would have been obliterated with almost all of its popu-lation killed immediately by the blast. The few survivors (or more likely witnesses from outside the city) would soon tell their tales, and the news would have spread quickly throughout the world. Eventually, the city would be rebuilt and have a monument in honor of the dead with some kind of remembrance ceremony every year. Under those circumstances, this upcoming centennial would be considered a somber occasion. While some alternate historians have suggested scenarios involving Moscow, that city is about five degrees south of the impact latitude. However, a number of major cities in Norway (Oslo, Bergen), Sweden (Uppsala, Stockholm), and Finland (Helsinki) are at about the same line of latitude and could have been targets. The only city in North America that could have been a target was Whitehorse, in Canada's Yukon Territory. Could History Repeat? It is entirely possible that there could be another event of this nature, as the odds are about once in 300 years. But, it probably isn't worth losing sleep over. Oceans cover about 75% of the Earth's surface. Contrary to popular belief, if a Tunguska-class event were to occur in the ocean, there would be no tsunamis. According to a recently declassified document, the American military researched the possibility of triggering tsunamis with nuclear weapons. Based on the data from the nuclear tests done in the Pacific, it was soon concluded that tsunamis could not be started in this fashion. So, an oceanic impact would pose little short-term threat outside the immediate blast area. However, if one took place in a populated region, the result would be a potentially record-breaking disaster, as I have described in the alternate history scenarios earlier in the article. But there are circumstances where a Tunguska-like event could produce even worse havoc. Consider an impact in India or Pakistan. Those countries lack the sophisticated surveillance satellites that would instantly peg the impact for what it was. A possible scenario is that the government in the impacted country could interpret the event as a first strike by the other country and launch a counter-attack. The other country would detect the counter-attack and think it is a first strike and reciprocate. By the time it could be shown that the initial event was a cosmic impact, there could be a mini-nuclear war. A slightly similar scenario could occur in Iran. Iran might assume that it was an Israeli attack and respond (probably by conventional weapons or in kind, depending on the state of Iranian weapons technology) with possibly other nations in the region joining in. Naturally, Israel would react. Regardless of where the impact takes place, there is one global consequence. For a number of years, Mt. Wilson observatory took spectra of the Sun every clear day in an effort to detect variations in the solar con-stant. In addition, the composition of our atmosphere could be analyzed as well. From 1909 to about 1911, there was about a 30% reduction in the ozone layer. The likely culprit was the Tunguska explosion which pro-pelled considerable amounts of material into the stratosphere, and it created large amounts of nitrogen oxides that destroy ozone. If this were to happen today with stratospheric ozone at a lower level than it was in the early 1900s (due to years of pollution), it could have some impact on humanity. Currently, the best defense against the situations I have described is surveillance. Objects the likely size of the Tunguska impactor (100 meters or so) would be difficult for current asteroid search programs to detect. However, if an impact does occur, every effort should be made to ensure that the government of the nation in which it takes place knows that it is of cosmic origin, and not an attack or an act of terrorism. While this won't prevent damage from the impact, it will keep a disastrous situation from getting even worse. After 100 Years Despite the passage of a century and much scientific study, some aspects of the Tunguska impact still remain a mystery. Perhaps we will have more answers before the 150th anniversary. So, on June 30th, why not take a moment to consider this strange astronomical event, which missed its opportunity to influence history, but had the study of it influenced by historical events far outside the realm of space science. Astronomy Picture of the Day 2005 1 January Explanation: Manicouagan Crater in northern Canada is one of the oldest impact craters known. Formed about 200 million years ago, the present day terrain supports a 70-kilometer diameter hydroelectric reservoir in the telltale form of an annular lake. The crater itself has been worn away by the passing of glaciers and other erosional processes. Still, the hard rock at the impact site has preserved much of the complex impact structure and so allows scientists a leading case to help understand large impact features on Earth and other Solar System bodies. Also visible above is the vertical fin of the Space Shuttle Columbia from which the picture was taken in 1983. EMAIL CONTACTS presi-dent@asterism.org President of AAI editor@asterism.org Editor of The Aster-ism Ray Shapp, Editor Deadline for submissions to each month's newsletter is the first Friday of that month. member-ship@asterism.org AAI Membership Chair trustees@asterism.org All three Trustees of AAI ray@asterism.org Ray Shapp for the website exec@asterism.org Executive Committee plus Trustees QOs@asterism.org All Qualified Observers Info@asterism.org AAI president, corresponding secretary, and computer services chair MEMBERSHIP DUES Regular Membership: $21 Sustaining Member-ship: $31 Sponsoring Member- ship: $46 Family Membership: $5 First Time Ap-plication Fee: $3 Sky & Telescope: $32.95 Astronomy subscription: $34 (Subscription renewals to S&T can be done directly. See "Membrship-Dues" on website for details.) AAI Dues can be paid in person to Membership Chair or Treasurer, or by mail to: AAI, PO Box 111, Garwood, NJ 07027-0111 DR. LEW'S SEMINARS See Dr. Lew Thomas for possible upcoming seminar topics. (Choice of topic at Dr. Lew's seminars is determined by par-ticipants' interest) DOME DUTY June 27 Team C July 4 Team D July 11 Team E July 18 Team A FRIDAYS AT SPERRY June 27, 2008 Ask The Astronomers Dr. Lew July 4, 2008 Observatory Closed July 11, 2008 What's Up: A Down-to-Earth Sky Guide Kathy Vaccari July 18, 2008 Going Globular, An Introduction to Globular Clusters John Sichel All schedules above were accurate at time of publication. Please check www.asterism.org for latest information (click on "Club Activities") July 2008 is the perfect summer month in the night sky. Venus is still on vacation, hiding near the setting Sun. Jupiter is showing off all night without any competition. And, best of all, Saturn, Mars, and Regulus start off the month by giving us a perfect image from ... baseball! Look to the west just after dark. That familiar bright pair of objects we've been following all year is getting low. At the lower right is Regulus, the heart of Leo the Lion. Think of this star as first base. Just five degrees to the upper left is Saturn. That must be second base. On the first evening of the month, Mars is standing on first base, less than one degree above Regulus. This is the year's closest conjunction of a planet and a first-magnitude star. For the first nine days of July, Mars runs to second base, sliding safely under Saturn on the ninth of the month. During the Independence Day fireworks Mars is almost exactly between the star and planet. The next eve-ning, the crescent Moon arrives on the scene to watch the game, but quickly moves off to the upper left. By the tenth, Mars has overshot Saturn and moves off into left field, as it continues doing for the rest of the month. Before the fireworks begin, there is a slim chance of catching Venus if you have a very clear and low west-ern horizon. Try about fifteen minutes after sunset. By the end of the month, the chances of catching the Brightest Planet have increased only slightly. After it gets dark, be sure to look low in the east. Jupiter is back again, rising just after sunset and reaching opposition from the Sun on the ninth. This is the closest and brightest opposition that Jupiter has given us for several years. For the rest of this year the Giant Planet is officially an evening object. Just to the right of Jupiter, look for a large asterism of eight stars. This is the very aptly named Teapot of Sagittarius, about to pour its contents to the right onto the tail of Scorpius. Slightly above Jupiter is a smaller, dimmer pattern of four stars called the Teaspoon. Above them all looms the Great Summer Triangle, with Vega in its familiar position near the zenith at the end of evening twilight. The Moon seems to willfully avoid close encounters with all the planets and bright stars this month. If you can catch a very thin crescent Moon on the first morning of the month, look for Mercury at elongation to its lower right. NASA Science Outreach and Update by Ken Kremer Phoenix Lands Safely on May 25 After a 10 month journey of more than 420 million miles, NASA's bold mission to the frigid Martian arctic region culminated on May 25 by plunging into the atmosphere at nearly 13,000 MPH to encoun-ter the hellish "7 Minutes of Terror". Protected by a heat shield as the external temperatures ex-ceeded 2500 degrees Fahrenheit, the 900 pound Phoenix spacecraft's descent was slowed by a combination of atmospheric friction, parachutes, and radar assisted rockets for a gentle landing at 7:53pm EDT at 68.2 degrees North. The site is named Vastitas Borealis and is believed to contain substantial amounts of water ice within about 2 inches of the surface. Radio signals were received from Phoenix to indicate the health of the spacecraft all the way to touchdown. This allowed mission controllers at JPL to proclaim instant success, whereupon applause immediately broke out at JPL and at other mission partners throughout the US and Europe as well as with space enthusiasts worldwide. Daring Flight of the Phoenix Credit: Ken Kremer and Marco Di Lorenzo using robotic arm camera imagery from NASA/JPL/University of Arizona/Max Planck Institute The image was featured as the Astronomy Picture Of the Day (APOD) on 12 Jun 2008, titled "Phoe-nix and the Snow Queen" Download image here: http://antwrp.gsfc.nasa.gov/apod/ap080612.html NASA Science Outreach and Update (continued) The first pictures of the heretofore unseen polar surface were transmitted to Earth about two hours later and they revealed a polygonal terrain with numerous troughs. "We can see cracks in the troughs that make us think the ice is still modifying the surface" said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson Descent of the Phoenix and Heimdall Crater: Imaged From Mars Orbit The powerful HiRISE Camera on board the Mars Reconnaissance Orbiter captured this spectacular and iconic image of Phoenix as it parachuted to the surface (inset left) about 12 miles in front of Heimdall Crater. This marks the first time in history that one spacecraft has photographed another one in the act of landing on another planet. Download image here: http://www.jpl.nasa.gov/images/phoenix/collection_16/ PSP_008579_9020_descent_800-600.jpg NASA Science Outreach and Update (continued) Left: This picture is one of the first images captured by NASA's Phoenix Mars Lander. It shows the vast plains of the northern polar region of Mars. The view is a mosaic of several images and it shows the terrain from in front of the lander out to the horizon. The flat landscape is strewn with tiny pebbles and it shows polygonal cracking (at bottom), a pattern seen widely in Martian high latitudes and also observed in permafrost terrains on Earth. The polygonal cracking is believed to have re-sulted from seasonal contraction and expansion of surface water ice. Download image here: http://www.jpl.nasa.gov/images/phoenix/collection_16/sol0final_800- 600.jpg Right: This remarkable color image from Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera shows the 18- foot wide Phoenix lander with its solar panels deployed on the Mars surface about 22 hours after the landing. Download image here: http://www.jpl.nasa.gov/images/phoenix/collection_16/ PSP_008591_2485_RGB_Lander_Detail_800-600.jpg NASA Science Outreach and Update (continued) Sol 3 Panorama First full Panorama from Phoenix on Sol 3 (Day 3 after landing): This 360 degree moderate resolution panorama is the first to show the complete view of the landing site and spacecraft. Both solar panels, the lander science deck, unstowed robot arm (left), and wind telltale (lower left) are visible. This is projected as an overhead, polar view combining numerous individual images. The different sun an-gles and the brightness levels have not been adjusted. Higher resolution full color views are being transmitted to earth over the next few weeks. Download image here: http://phoenix.lpl.arizona.edu/images/gallery/lg_812.jpg NASA Science Outreach and Update (continued) Phoenix has unfurled its 8-foot long robotic arm which is designed to scoop down about two feet into the frozen Martian soil. Samples of the soil have just been delivered for analysis to two of the ad-vanced science instruments on board: TEGA bake and sniff oven and the MECA optical microscope. The purpose is to search for water, organic molecules, and any signs of an environment favorable for microbial life. Phoenix images have been featured as the APOD on May 25, 26, 27, 30, and Jun 2, 8, 12 (Ken's mosaic) and Jun 15. Learn more and hear a Phoenix update at my UACNJ talk on Saturday, Jun 28 and complete mission details at my AAI talk on Dec 19 (details below). Phoenix Website: http://phoenix.lpl.arizona.edu/index.php Astronomy Outreach NEAF: Half of the big crowd for my talk on DAWN, Phoenix, and the Mars Rovers at the NorthEast Astronomy Forum on Saturday, April 26, 2008 learning about ion thrusters. Please contact me for more info or science outreach presentations by email. My upcoming Astronomy talks include: United Astronomy Clubs of New Jersey (UACNJ) at Jenny Jump Observatory/Park: Hope, NJ, Jun 28, Sat, 8 PM. "Twin Robots Exploring Mars (in 3-D.)" Website: http://www.uacnj.org/Stella Della Valley Starparty and BucksMont Astronomical Association (BMAA): Ottsville, PA, Oct 25, Sat. "Launching DAWN to Asteroids: From Behind the Scenes at Kennedy Space Center." Amateur Astronomer's Inc (AAI) at Union County College: Cranford, NJ, Fri, Dec 19, 8 PM. "Dar-ing Flight of the Phoenix." Website: http://www.asterism.org Dr. Ken Kremer Email: kremerken@yahoo.com NASA JPL Solar System Ambassador