Innholdsfortegnelse for Apr 2016 i Australian Sky & Telescope

There’s no doubt about that Mr Einstein — his ideas can still make a splash, even 100 years after the fact. As part of his revolution in the understanding of gravity, he predicted that, in certain circumstances, energy is lost from systems in the form of gravitational waves — ripples in the very essence of space and time. Although they were first indirectly detected in the 1970s and ’80s through measurements of energy loss in binary pulsar systems (which work led to the Nobel Prize for Physics in 1993), the announcement of the detection of gravitational waves by the international Laser Interferometer Gravitational-wave Observatory team is the first ever direct measurement of these fleeting waves. This result is huge — easily on a par with the discovery of the Higgs…

On December 17, China launched its first astrophysics payload. The Dark Matter Particle Explorer (DAMPE) will detect energetic particles known as cosmic rays, as well as gamma-ray photons from supernovae, pulsars and other astrophysical sources — including, perhaps, elusive dark matter. DAMPE is a collaboration among universities in Switzerland and Italy and the Chinese Academy of Sciences. (NASA is restricted from trading technology with China due to the 1976 International Trade in Arms Regulations, a key reason why China isn’t a partner on the International Space Station.) DAMPE joins the Alpha Magnetic Spectrometer and the Calorimetric Electron Telescope, both aboard the International Space Station, in taking the dark matter hunt to space. It’s the first of a five-mission series, with the next two payloads — a quantum-communications satellite and an…

In October 2012 Australian amateur Michael Sidonio used his 30-cm reflector and FLI Proline 16803 CCD camera to record frames of the Sculptor Galaxy, NGC 253. All Sidonio wanted was a pretty image of this intermediate spiral galaxy, which lies about 11.5 million light-years away. But later he noticed a small, elongated smudge off to one side that wasn’t plotted on any of his reference charts. His chance discovery triggered a succession of observations with ever-larger professional telescopes — culminating with Japan’s 8.2-metre Subaru Telescope. That little smudge, now designated NGC 253-dw2, turns out to be a dwarf spheroidal galaxy that the much bigger spiral galaxy is in the process of gobbling up via tidal disruption (as implied by its elongated shape). This straggler lies about 160,000 light-years from NGC…

Astronomers Predict a Supernova. Last year, Patrick Kelly (University of California, Berkeley) and colleagues announced the discovery of Supernova Refsdal, an exploding star in a faraway galaxy whose light had been split into four images on its way to Earth by an intervening galaxy’s gravity. A flurry of computer simulations published immediately after the discovery predicted that another image would be found within one to several years, due to the effect of the lensing galaxy’s home cluster, MACS J1149.5+2223. On December 11, Kelly’s team spotted the predicted fifth image of the exact same explosion, more than a year after Hubble caught the previous four images.…

Generations of amateur and professional astronomers have viewed and studied Jupiter’s Great Red Spot (GRS), one of the giant planet’s most easily recognised features. It joins Saturn’s rings and the Martian polar caps as ‘must see’ features for Solar System enthusiasts. But the GRS is an inconstant icon. In fact, in recent years observers have become increasingly alarmed about how small (relatively speaking) the spot has become. Visually it’s far less impressive than it was two or three decades ago. So planetary scientists have begun to ask whether this huge cloud system is really shrinking and, if so, might it someday disappear completely? The answer to the first question is unequivocally yes, but the second one remains a mystery. Given that Jupiter has other small, enduring, red-hued ovals, perhaps the…

WHEN Early March 10pmlate March 9pmEarly April 8pmlate April 7pm These are standard times — add Daylight Savings if it applies to your location. HOW Go outside within an hour or so of a time listed above. Hold the map above your head with the bottom of the page facing south. The chart now matches the stars in your sky, with the circular perimeter representing the horizon and the centre of the chart being the point directly over your head (known as the zenith). FOR EXAMPLE: look at the chart, and you’ll see that the bright star Achernar at the end of the constellation Eridanus (The river) is about one-third of the way from the southwestern horizon and the middle of the chart. So if you look to the southwest,…

Video-assisted observing has become increasingly popular among amateur astronomers in recent years. Part of this trend is due to the growing problem of light pollution; video can show you far more from a typical suburban backyard than the same telescope can by eye at dark site. In fact, enhancing your observing experience with an astrovideo camera reveals objects in the night sky as unambiguous galaxies, nebulae and star clusters, rather than as the vague smudges they often seem through an eyepiece. But more than this, an astrovideo camera can virtually increase the aperture of your telescope by a factor of three or more at a fraction of the cost of a larger scope. Amateurs have been mating their telescopes with video cameras since the early 1980s. Video cameras at the…

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 20-22, 2016 Annual meeting of New Zealand’s astronomers hbastrosoc.org.nz/rasnz-conference-2016/ South Pacific Star Party May 5-8, 2016 Annual star party hosted by the Astronomical Society of NSW asnsw.com/spsp Queensland Astrofest August 2016 Lions Camp Duckadang, Linville, Qld Long-running annual star party www.qldastrofest.org.au National Science Week August 13-21 Various activities around the nation www.scienceweek.net.au Siding Spring…

Astronomers have detected magnetic fields dancing in the skirts of the Milky Way’s central black hole. The work is part of the Event Horizon Telescope, a planet-spanning network of radio antennas aiming to ‘see’ a supermassive black hole — or, rather, its telltale silhouette amid the glow of hot gas surrounding it like a superheated tutu. Michael Johnson (Harvard-Smithsonian Center for Astrophysics) and other members of the EHT collaboration used telescopes in Hawai‘i, California and Arizona to peer into the inner sanctum of our galaxy’s black hole, Sagittarius A*. With only three sites and a few nights’ worth of observations, they couldn’t reconstruct a complete image — instead of seeing the whole elephant, they’re only seeing an ear and a bit of trunk. But those bits are good enough for…

A new radio survey suggests that binary star systems come in two basic sizes: tight and loose. John Tobin (Leiden Observatory, The Netherlands) and others used the Very Large Array’s 27 antennas to study newborn stars in a nearby molecular cloud in the direction of Perseus. The team noticed that most of the young binary star systems in the cloud fall into two categories: they’re either separated by less than 300 astronomical units or by a distance greater than 1,000 a.u. “We think this is evidence that they form from distinct routes,” Tobin said during a January 5 press conference at the American Astronomical Society’s January meeting. Stars are born in enormous clouds of gas and dust that collapse into clumps under the pull of gravity. As the clumps shrink,…

Anew study shows that about half of Kepler’s giant exoplanet candidates aren’t real planets. That might sound surprising, but it’s not: astronomers expected this result. The Astronomy & Astrophysics study, by Alexandre Santerne (University of Porto, Portugal) and colleagues, followed up on potential giant planets detected by NASA’s Kepler satellite, which over four years found more than 4,700 exoplanet candidates. Santerne’s team conducted six observing campaigns with the 1.93-m telescope at Haute-Provence Observatory in France, looking for the worlds’ tiny gravitational tugs on their stars. The instrument wasn’t accurate enough to detect small planets, so the team focused on giants with orbits of less than 400 days. The team observed 129 Kepler candidates. Of these, only 45 turned out to be bona fide planets. The rest were brown dwarfs (3)…

Part scientist, part engineer, and part therapist — that’s the job of telescope operators. Many large research telescopes — from the W. M. Keck Observatory in Hawai‘i to the Boeing-borne Stratospheric Observatory for Infrared Astronomy (SOFIA) — employ these jacks- and jills-of-all-trades. TOs, as they’re commonly called, are tasked with ensuring the perfect performance of a telescope and its cadre of instruments. They spend their nights working on remote mountaintops and airborne observatories as the liaisons between data-hungry astronomers and complex telescopes worth millions of dollars. TOs are an integral part of a big-scope observing run because professional astronomers, for all their scientific expertise, often use a particular telescope and instrument combination no more than a few nights each year. These guest observers accordingly lack the day-in, day-out practice of…

What can planets do that stars can’t? One thing is to move into conjunction with another celestial object. Much of the beauty — and all of the drama — of conjunctions is that they’re temporary and evolving celestial events. But some of the beauty is also just in the vision of two luminaries posing close to each other in the sky. The stars can offer us this too. And let’s not forget that ‘close’ is relative — how close together, for instance, do two 1st-magnitude stars have to be to constitute an astronomical marvel? Last year was the one I called ‘the Year of the Conjunctions’. Several times, pairings featured bright planets less than 1/2° degree apart when they were high in a fully dark sky. One more such really…

. . . the sky Spreads like an ocean hung on high, Bespangled with those isles of light, So wildly, spiritually bright; Who ever gazed upon them shining, And turned to earth without repining, Nor wished for wings to flee away, And mix with their eternal ray? — Lord Byron, The Siege of Corinth, 1816 Gemini is one of the most vividly starred constellations of the zodiac. Our Sun dwells in the Milky Way Galaxy near the inner edge of a spiral-arm segment known as the Orion Spur or Local Arm — when we gaze at Gemini, we’re looking outward through this arm and are rewarded with the sight of many nearby stars brightly adorning our sky. All of its stars bearing Greek letter designations lie within the Orion Spur,…

One side of Mars is fairly blank; the other is more feature-rich. To identify surface features you see through the eyepiece, you’ll need to know which side of Mars is facing you. To find out, enter the time and date when you plan to observe into our Mars profiler, at SkyandTelescope.com/marsprofiler. Choose the correct orientation to match your telescope, and compare the map section you get you to the map and disks printed at left. Out observing, you’ll find that Mars presents nearly the same face from night to night. This is because the Martian day is only 38 minutes longer than Earth’s. To see other parts of Mars, you have to observe at a different time of night, travel to a different longitude on Earth or wait for a…

How can deep sky video cameras produce recognisable pictures of galaxies in 10 seconds when a DSlr camera would need a minute or more? it’s partly a matter of pixel size. The bigger the pixels on the light sensor, the more light falls on each pixel in a given exposure and the better the low-light sensitivity. point-and-shoot cameras are poor choices for deep sky photography because they have tiny sensors (to keep their zoom lenses compact) divided into huge numbers of pixels — which is largely a marketing gimmick. A full-page photograph reproduced in this magazine needs just 6 to 8 megapixels. DSlrs have about the same pixel count as point-and-shoots, but their sensors are much bigger. That makes each pixel bigger, giving the camera very good sensitivity when operating…

TRAIL MIX Tim Bruton Almost 500 images have been stacked to produce this image of the southern sky, which comes complete with Alpha Centaurid meteors. Tim used a Canon EOS 6D, Samyang 14-mm lens at f/2.8, and 30-second images at 4-second intervals. Processing was done in StarStaX. ORION OBJECTS Paul Haese Paul has captured several objects in this field in Orion, including NGC 1999, which is the small, bright patch with a black core just below and to the right of centre. He used a FSQ 106ED scope and QSI683-8 camera, for a combined LHaRGB exposure of 21.8 hours. METEOR MOMENT Richard Brown Richard set out to capture a rarely photographed Alpha Crucid meteor in mid-January, and was successful. The Alpha Crucid shower typically has only three meteors per hour…

Triumph is never sweeter than when following defeat. At 23:51 Universal Time on December 6, Japanese Aerospace Exploration Agency (JAXA) engineers executed an innovative contingency plan to get the Venus Climate Orbiter, named Akatsuki, to its destination. The success came five years to the day after a main-engine failure caused the spacecraft to fly past Venus instead of going into orbit. The spacecraft ran into trouble in 2010 when its main engine failed to execute a planned 12-minute firing. Telemetry analysis showed a pressure drop caused by a faulty valve in the main engine, which resulted in burning an oxidizer-rich mixture beyond normal limits. The failure overheated and destroyed much of the engine. With the primary means of propulsion ruined, scientists and engineers scrambled to recover the mission while the…

InSight launch Postponed Until 2018. NASA’s next Mars-bound mission, InSight (short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport), will not be launched this autumn as planned. A vacuum seal in the lander’s French-built seismometer developed a leak during a final round of thermal testing at Vandenberg Air Force Base in California. Mission managers decided that there wasn’t enough time to make the needed repairs before the launch. Since the opportunities to send spacecraft to Mars occur during favourable orbital geometries that occur every 26 months, InSight won’t get another chance to leave Earth until 2018.…

The Infinity breaks the barrier between visual observing and astrophotography. It combines the experience of observing at the eyepiece with a level of depth and detail that would traditionally be the result of several hours processing. This takes a camera that's sensitive enough to capture faint details on distant objects, and fast enough to do it in real time. It then takes our powerful, intuitive software to bring stunning views of the night sky to a screen in just seconds. This recreates the feel of observing in the field through a very large telescope, only using much more modest equipment. You stay connected to the night sky, watching satellites drift across your field of view, while viewing objects previously out of reach to all but the most powerful eyepieces and…

We’ve known for centuries that, as the Moon revolves around Earth, it shows us only one face. Before the Space Age, scientists could only speculate about the moonscape hidden on the lunar farside. Informed expert opinion was that the farside probably looked similar to the nearside, with extensive low, smooth maria (Latin for ‘seas’) set in rough, undulating highlands (terrae). With the advent of spaceflight in the late 1950s, we finally saw the farside. That momentous event first occurred in 1959 thanks to the photographs captured by Luna 3, an automated satellite sent to the Moon by the Soviet Union. Those first farside pictures were of poor quality and low resolution, but planetary scientists immediately realised that the near- and farsides are fundamentally different. The farside as seen from Luna…

Few approach binocular astronomy as a competitive sport, but it’s unquestionably rewarding to challenge yourself from time to time. Running a Messier marathon is a great way to sharpen your observing and planning skills — with particular emphasis on the latter. What’s a Messier marathon? Simply an attempt to see as many Messier objects as you can in a single, dusk-to-dawn session. What are the secrets to success? First, as I mention above, planning is very important. Have your charts ready and print an observing list that includes a logical sequence. Use Larry McNish’s Messier Marathon Planner (http://is.gd/mmarathon) or a similar tool to generate one tailored to your location and date. Second, find an observing site with dark skies and good horizons, especially in the east and west. Third, bring…

Sometimes a familiar celestial object turns out to be not so familiar after all. Messier 44, the naked-eye patch of nebulosity in the constellation of Cancer, the Crab, has been under observation since antiquity. It may be better known as the Beehive, but it’s had many names. The Greeks and Romans saw a manger here; the Latin Praesepe remains a popular label for the cluster. In China, the starry cluster was long interpreted as a group of captured spirits or demons, Yugui. Perhaps the most offcial is its designation as NGC 2632, or Collinder 189. It’s relatively nearby, maybe 600 light-years distant, and composed of about 1,000 stars, the 50 or so brightest comprising the familiar cluster we observe through small telescopes. Many speculate that Charles Messier added it to…

I’ve long felt that the ideal deep sky machine is a big-aperture scope on an equatorial mount. Sure, most of us adapt readily enough to pushing our Dobsonians along to keep a target centred through the eyepiece, but there’s no denying that it’s much nicer to be able enjoy the view without the fuss. Thanks to the advent of equatorial platforms, we can luxuriate in hands-free observing without the weight and bulk of a regular German equatorial mount. But the problem with many platforms is they usually add quite a few centimetres to the height of the eyepiece. That sounds minor, but it can be the difference between needing a ladder or not — and that’s a big deal. Over the years this magazine has featured several equatorial platforms, but…