Innholdsfortegnelse for Jan 2016 i Australian Sky & Telescope

It’s now a little over 100 years since the world woke to the news of one of the most amazing intellectual accomplishments our species has ever known, with the publication of Albert Einstein’s general theory of relativity (GR). And although his incredible leap in cosmic comprehension wasn’t fully appreciated at the time — or for some years after in fact — GR has come to represent the most elegant and deceptively simple model of reality ever conceived. Not only has GR changed our view of the cosmos, it has also changed our understanding of the very concepts of space and time. And what also is so remarkable about it is that has passed every test thrown at it, and has been used to make successful predictions for real phenomena that…

New mid-size black hole. Astronomers think a bright X-ray source in the galaxy NGC 1313 is an intermediate-mass black hole (IMBH). These elusive objects should range from a few hundred to a hundred thousand solar masses. Most IMBH candidates are iffy contenders. In 2014, Dheeraj Pasham (NASA Goddard) and colleagues weighed a potential IMBH using quasi-periodic oscillations (QPOs), cyclic blips in a black hole’s X-ray signal that astronomers suspect are related to the object’s mass. The team calculated a mass of roughly 400 Suns for the object, which lies in the galaxy M82. Now, the team estimates that a QPO-producing object in the galaxy NGC 1313 has a mass between 3,700 and 6,300 Suns. This would easily put it in the IMBH family and add to growing evidence that black…

Astronomers have detected waves working together in the solar atmosphere, creating turbulence that superheats the corona’s ionised gas. The Sun’s corona is more than a hundred times hotter than the photosphere below it. One explanation for this temperature surge is Alfvenic waves, motions in the solar plasma governed by the magnetic field. The corona is essentially a sea of these waves. Solar physicists think that the waves carry enough energy to heat the corona — but pinning down how the magnetic motions do it has been tough. New spacecraft observations, coupled with computer simulations, might solve the mystery. Takenori Okamoto (JAXA), Patrick Antolin (National Astronomical Observatory of Japan), and their team watched threads of superheated plasma wiggle in 3D in a coronal filament. These prominences are cooler and denser than…

Touching down on another world remains a rare and exciting event. It hadn’t happened at all, of course, until the dawn of the Space Age nearly sixty years ago, and for most of the years since such encounters were limited to nearby bodies of the Solar System. We have made soft landings (ie. the package of instruments survived in working order) on the Moon many times, on Mars quite a few times, and even on Venus and a comet. But only once was the target situated in the outer Solar System, in the vast realm beyond the asteroid belt where the giant planets rule. That meeting was with Saturn’s largest moon, and it took place on January 14, 2005, barely a decade ago. The spacecraft was called Huygens, named after…

General relativity says that gravity is nothing more than an object’s tendency, in the absence of any force on it, to follow a straight line (technically a ‘geodesic’) through curved 4D spacetime. Earth bends spacetime by only a very tiny amount. So why does a ball that you toss into the air look like it follows a sharply curved arc? How can that arc be anything like a straight line? You have to think in 4D. In this perspective, the time dimension is just an extra space dimension that we’re plunging through at the speed of light. In this framework, when you toss a ball from one hand to the other, the 1 second in which the ball may be in flight is an enormous 1…

If I had to choose just one deep sky object to demonstrate the appeal of binocular astronomy, it would probably be the Pleiades (M45) in Taurus. The cluster has two things going for it. First, you can see it without optical aid, which means even casual stargazers are drawn to it. Second, the Pleiades are visually impressive through any binocular under a wide range of sky conditions. You don’t need pristine country skies to appreciate the splendour of this deep sky wonder. The Pleiades have inspired countless observers. In his 1965 memoir, Starlight Nights, famed variable star observer and comet hunter Leslie Peltier recounts an early childhood view of the cluster and describes it as his “first meeting with the stars.” Keen-eyed observer Stephen James O’Meara poetically likens the sight…

The dark maria are the most conspicuous features of the Moon, but more important are the giant basins that contain them. Each basin controls the geology of the area around it. One easy-to-see example is the Humorum basin, whose central depression is partially filled by the lava plains of Mare Humorum. This mid-size impact basin preserves many structural features that one can appreciate only by careful observation. So let’s do so! Younger, less-modified lunar basins (Orientale comes to mind) are defined by multiple concentric mountain ranges. We assume that the Humorum basin had them as well when it formed, but only a few fragments of the original rims survive. Can you see any? The basin’s best-seen rim segment appears as a short lumpy ridge (once known as the Percy Mountains)…

How much does a decent beginner scope cost? There are plenty of good choices for around $550, and the options are almost limitless if you’re willing to spend more. At the opposite extreme, it’s possible to buy a good telescope for as little as around $150. But $150 scopes have very small apertures and limited capabilities. Things change when you move up a notch in price. If you shop carefully, a $300 telescope can provide very good views of planets and deep sky objects. But how do telescopes in this same price range compare? While searching for good telescopes in the $300 price range, we evaluated many scopes and have included three of them here — the Meade Infinity 90mm altazimuth refractor, the Orion StarBlast 4.5 reflector and the Astronomers…

Rosetta observations confirm that the ‘rubber ducky’-shaped nucleus of Comet 67P/Churyumov-Gerasimenko was likely born when two individual objects in the outer Solar System gently collided and stuck together. Matteo Massironi (University of Padova, Italy) and colleagues used images from Rosetta’s Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) to investigate the nucleus’s origin. The scientists peered down into pits and along terraces and cliffs across the nucleus. They found strata like those seen in sedimentary rock on Earth, built up as the bodies formed one layer at a time. In some places the layers reach 650 metres deep, a fair fraction of the kilometres-long nucleus. You can think of them like the layers in an onion, the team explains in the journal Nature. If Comet 67P’s layering arose during the…

Observations of two cool white dwarfs show irregular outbursts in the stars’ otherwise steady rhythm of pulsations. Pulsating white dwarfs, or ZZ Ceti stars, are a type of white dwarf that glows and fades in a steady rhythm. White dwarfs start to pulse when they cool from an initial temperature of around 100,000K to about 12,600K. The atmosphere becomes a mix of ionised and neutral hydrogen atoms, and this mix stores and releases energy in regular intervals of a few minutes, driving pulsations. These make the white dwarf brighten and fade by a few percent in regular beats, like a person’s rhythmic breathing. The star continues to cool slowly over time, but once it falls below about 10,800K, it ceases pulsating altogether. Using Kepler data, which has far fewer gaps…

Just over 70 years ago, a plutonium reactor at the US Department of Energy’s Hanford Site, north of Richland, Washington, produced the nuclear fuel for the atomic bomb that exploded over the Japanese city of Nagasaki. Now, the desolate area is home to a very different kind of physics project. Here, one of the most sensitive scientific instruments ever built is poised to detect elusive spacetime ripples from the distant universe. Researchers have recently outfitted the Laser Interferometer Gravitational-wave Observatory (LIGO) at Hanford with powerful new lasers, ultra-stable mirrors and superfast computers for data analysis to dig out the waves’ weak signal. “People will be very surprised if nothing is found,” says observatory head Frederick Raab. Other scientists are equally optimistic. At the 11th Edoardo Amaldi Conference on Gravitational Waves,…

Are you ready to celebrate a happy New Year? In today’s international secular calendar, the first day of the year is, of course, January 1st. But this has been far from the case in many individual cultures and times. Let’s take a look at a few of these — they’re all based on astronomy and a few on the positions of very specific stellar objects. Then let’s see how, during a January evening of observing, we can celebrate several different times we might regard as a fitting start of a celestial calendar or clock. Welcome to January, the eleventh month. The ancient Roman calendar began with March. That’s why September through December have the root words for seven through ten in their names: they were the seventh through tenth months…

Early January provides the last chance for observers at mid-southern latitudes to see C/2013 US10 (Catalina) as it sinks below the northern horizon on its way out from the Sun. This comet was a nice binocular object during the early spring of last year as it cruised the southern circumpolar skies while sporting a short, tapering dust tail. Passing perihelion at 082 a.u. on November 15 the comet remained too close to the Sun in the skies until December when it emerged low in the morning twilight. Continuing its northward trek, Catalina begins the New Year in Bootes, close to the bright star Arcturus, very low in the north-east before dawn from mid-southern latitudes. By the middle of January however, it will be far north, passing quite close to the…

Jupiter in January grows from 39 to 42 arcseconds wide. Any telescope will show its four big Galilean moons. Binoculars almost always show at least two or three. Below are the times, in Universal Time, when Jupiter’s Great Red Spot should rotate across the planet’s central meridian. The dates, also in UT, are in bold. December 16, 0:47, 10:42, 20:38; 17, 6:34, 16:29; 18, 2:25, 12:21, 22:16; 19, 8:12, 18:08; 20, 4:03, 13:59, 23:55; 21, 9:50, 19:46; 22, 5:42, 15:37; 23, 1:33, 11:29, 21:24; 24, 7:20, 17:16; 25, 3:11, 13:07, 23:03; 26, 8:58, 18:54; 27, 4:49, 14:45; 28, 0:41, 10:36, 20:32; 29, 6:28, 16:23; 30, 2:19, 12:15, 22:10; 31, 8:06, 18:02. January 1, 3:57, 13:53, 23:48; 2, 9:44, 19:40; 3, 5:35, 15:31; 4, 1:27, 11:22, 21:18; 5, 7:14, 17:09; 6,…

Want something new to do with your telescope? If I can interest you in joining our project, please know we’d love to have your help. And now with that much said, let me back up and start at the beginning. You and I know the sky is filled with double stars. Almost every time we study star fields with our telescope, we’ll see that one of the stars is actually two stars, barely separated with magnification. If you’ve seen any of the showcase pairs, you know they can have breathtaking colours. But we don’t always know that we’ll see a double star, even when the star is known to be one. If a pair is made of stars not fainter than 6th magnitude and not drastically unequal in brightness, you…

I’ve been waiting since the 1980s. Now it’s happening. We’re getting an expanded, updated successor to the legendary Burnham’s Celestial Handbook. Someday, I was sure, the next heir would be born to a long and distinguished literary line founded 171 years ago: big, chatty, history-and science-rich guidebooks for telescope enthusiasts, arranged alphabetically by constellation. Admiral William Henry Smyth founded it in 1844 with The Bedford Catalogue (Volume 2 of his A Cycle of Celestial Objects); it’s still in print. Carrying the line forward were the Reverend T. W. Webb’s Celestial Objects for Common Telescopes (first published in 1858); William Tyler Olcott’s slimmer A Field Book of the Stars (1907, with many editions following); C. E. Barns’s 1001 Celestial Wonders (1929); Professor E. J. Hartung’s Astronomical Objects for Southern Telescopes (1968)…

With the 30th anniversary this March of the Soviet Vega missions — a pair of spacecraft that investigated Venus before flying past Halley’s Comet in March 1986 — I’m reminded again of an amusing event in the former USSR in which I played an indirect role. The event speaks volumes about a bygone era when the Soviet Union was both a planet-exploring powerhouse yet also distinctly less progressive on the public morals front. It concerns the depiction of Aquarius on a Soviet stamp — one that shows the zodiacal water-bearer quite untraditionally swathed in a kind of loincloth. For almost 60 years I worked where I was born, in Moscow. In the last decade of my Muscovite life, fate chose to place me on the Artistic Advisory Board of the…

Astronomers have confirmed that the quasar PG 1302-102 is probably a binary supermassive black hole, its components less than a tenth of a light-year apart. Recently, Matthew Graham (Caltech) and colleagues found several dozen quasars glowing with regular beats, one of which was PG 1302-102. This discovery surprised them, because black holes are usually fickle emitters. The best explanation for the periodic behaviour was that the quasars are actually two black holes spiraling toward each other. The years between signals would then be the orbital period. But scientists didn’t know why the periodicity exists. Daniel D’Orazio (Columbia University) and colleagues now think they have the answer. They realised that, if a smaller black hole were circling a larger one, we would see a Doppler boost in the quasar’s emission. Doppler…

Indian astrophysics got a boost on September 28 when the Indian Space Research Organisation (ISRO) launched the Astrosat spacecraft into a low-altitude orbit. The multipurpose observatory will study the universe across the X-ray spectrum, accompanied by simultaneous visible- and ultraviolet-light observations. India has successfully sent spacecraft to the Moon and Mars and, more recently, has lofted X-ray detectors aboard high-altitude balloons and suborbital sounding rockets. But this is ISRO’s first astronomical satellite. It’s capable of studying everything from nearby white dwarfs, pulsars and supernova remnants to faraway galaxy clusters. Its data will be available to the Indian astronomy community via proposals for observations. Astrosat’s five instruments each observe a different wavelength range. They comprise low-resolution X-ray spectral instruments, a binocular Ritchey-Chretien telescope, and a detector with a huge 10°- by-90°…

The summer of 1963 was eventful by any standards. In June, US President Kennedy proclaimed “Ich bin ein Berliner” to the beleaguered citizens of Berlin. In July the spy Kim Philby defected to Moscow. In August Martin Luther King, Jr., declared “I have a dream” to a crowd of a quarter million. And quietly, around the swimming pool of a suburban house in Dallas, Texas, three European emigres drank strong martinis and planned how to resurrect Einstein’s general theory of relativity. That theory is our modern theory of gravity. It took him eight hard years to figure out, but its essential formula fits on one line. Published on December 2, 1915, it transformed our understanding of what gravity is. Einstein had abolished the gravitational ‘force’ proposed by Isaac Newton, which…

Each year we scour the marketplace searching for what we consider to be some of the year’s most exciting new products. To make our list, a product must not only be new but should also introduce new technologies or processes, provide a solution to an old problem, or simply deliver exceptional value. Our Hot Products list for 2016 includes a variety of gadgets ranging from robotic telescope mounts to cameras, observing aids, and, of course, telescopes and eyepieces. This year many products caught our eye because of their exceptional value — equipment that offers features and performance at a cost well below that of similar items in the past. We hope you enjoy reading about these innovative products that piqued our interest as of late 2015. 1 MORPHEUS EYEPIECES Baader…

Warm summer nights are ideal for stargazing, no matter whether it’s just catching a glimpse here and there as we go about our other daily activities, or during dedicated observing sessions under our clear, southern skies. The innermost planet, Mercury, will be very low on the western horizon at the start of January, soon disappearing into the Sun’s glare before returning to our pre-dawn skies in the east at the end of the month. Venus will be a stunning sight out to the east in the pre-dawn sky until the end of April. Shining brightly at around magnitude –4.0, the cloud-covered planet cannot be missed. Watch for the Moon, Saturn and Scorpius’ brightest star, Antares, nearby on the 7th. Saturn will move a bit closer over the following two nights,…

As Leonardo da Vinci once observed, “art is never finished, only abandoned.” To some extent, this is also true of home-built telescopes. We often abandon a project when it’s reached a stage of completion advanced enough to be functional. Usually we do so knowing we’ll return to it again and again to make modifications or add features, as our needs and desires evolve with experience. And so it is with this issue’s telescope. “What you see here is an ongoing project with an accumulation of improvements to a telescope I began designing seven years ago,” says Ken George. Like many telescope makers, Ken started off with a specific goal in mind. “From the beginning, this was meant to be my ultimate planetary dream scope, with a focus on portability while…

Stardate North Island January 7-11, 2015 Annual New Zealand star party, to be held near Carterton in the Wairarapa. Email hellfa@xtra.co.nz  for details Stardate South Island February 5-8, 2016 The companion even to Stardate NI, to be held at Staveley. treesandstars.com/stardate/ Astrofest 2016 March 12, 2016 Australia’s largest free public astronomy event, held at Curtin Stadium on the Curtin University campus in Bentley, Perth. astronomywa.net.au National Australian Convention of Amateur Astronomers March 25-28, 2016 Held every second year, the NACAA is Australia’s premier get together for amateur astronomers to discuss research projects and the latest technologies. In 2016 it will be hosted by the Sutherland Astronomical Society in Sydney. nacaa.org.au Royal Astronomical Society of NZ Conference May 2016 Annual meeting of New Zealand’s astronomers hbastrosoc.org.nz/rasnz-conference-2016/ South Pacific Star…