Innholdsfortegnelse for February/March 2019 i Australian Sky & Telescope

IF THERE’S ANYONE WHO KNOWS a thing or two about amateur telescope making, it would have to be Mel Bartels. Famous for his innovations over the years, Mel just keeps them coming with his new design for a mount that eliminates the annoying ‘Dob’s hole’ effect (as you can see in Jerry Oltion’s Astro Workbench column in this issue, page 70). This, combined with a clever new style of Crayford focuser (from Pierre Lemay) has produced a superb new large-aperture, fairly compact instrument for serious deep sky work. Seeing Mel’s new scope and all the other marvellous and ingenious gadgets that Jerry features in his column, got me wondering about how much amateur telescope making still goes on out there. ATMing used to be the main way in which amateurs…

THE PAST DECADE HAS seen astronomers’ understanding of the Magellanic Clouds — two dwarf galaxies near the Milky Way — completely overthrown, resulting in new revelations about the violent and ongoing formation of our own galaxy. Now, a team led by Sally Oey (University of Michigan) has made a discovery that bears out predictions that these two galaxies once collided: A big chunk of the Small Magellanic Cloud (SMC) is moving toward the Large Magellanic Cloud (LMC) and the Magellanic Bridge of gas and stars that joins them. Astronomical wisdom once held that the LMC and SMC had been orbiting the Milky Way for billions of years, but a landmark study in 2007 showed that the dwarf galaxies are likely falling toward the Milky Way for the first time. That…

WE LIVE IN A BIG disk galaxy, a whirligig pancake that’s enshrouded in a halo of old stars. And increasingly, astronomers suspect that very early in our cosmic pancake’s history, a collision messed up the serene stellar disk and donated the detritus that makes up much of the halo. Reporting in the November 1 issue of the journal Nature, Amina Helmi (University of Groningen, The Netherlands) and colleagues confirm that a previously noted horde of nearby stars in the halo is quite unusual. These stars rotate around the galactic centre in the opposite, or retrograde, direction compared to other stars in the disk. They also have different chemical compositions to those in the disk. The strange characteristics suggest that these stars aren’t indigenous to the Milky Way — rather, they’re…

THE US-BASED LIGO PROJECT and its European compatriot, Virgo, will forever be hailed for opening up the field of gravitational-wave astronomy. LIGO and Virgo are tuned to a relatively high-frequency band of the gravitational-wave spectrum, giving them the ability to hear chirps coming from the death spirals of neutron stars and relatively low-mass black holes. But despite their success, both instruments are deaf to the greatest of cosmic cataclysms: the inspiral and merger of two supermassive black holes. In this sense, gravitational-wave science right now can be likened to the era when astronomers could study only visible light. Fortunately, radio astronomers will soon be opening a new window in the gravitational-wave spectrum, enabling scientists to catch the collisions of much larger objects. Using pulsars scattered across the galaxy, teams based…

We usually shorthand the concept of entropy to ‘disorder’ or ‘randomness’. More specifically, it’s related to the number of microscopic ways that a macroscopic system can be in a particular state — the higher the number, the greater the entropy. For example, a shiny new car has a relatively small number of ways that its molecules can be arranged such that the car still qualifies as shiny and new. But there’s a far greater number of ways that the car can look old — myriad possibilities for dents, rust spots and so forth. The ‘old’ state thus has a higher entropy than the ‘new’ state.…

Mars is our only easy-to-see evening planet during February and March, while the morning sky will be the domain of Venus, Jupiter and Saturn — all of them in a line — and, at the end of March, Mercury. Starting with Mercury (about magnitude –1 and 5.5" wide, mid-February), the tiny planet hugs the western evening horizon during February and will be very hard to spot, rising only a few degrees into the sky. The first half of March won’t be any better as the planet heads for inferior conjunction (between Earth and the Sun) on the 15th. Thereafter it will reappear above the eastern pre-dawn horizon in the last week of March, followed by a period of good observing conditions during April. Venus (–4.2, 17.2" mid-February) is dominating the…

There’ll be lots of exciting events coming up in 2019, especially those in July associated with the 50th anniversary of the landing of Apollo 11 on the Moon— watch this space and the AS&T website (skyandtelescope.com.au) for details of those events as they are announced. The World Science Festival returns to Brisbane in March, with an amazing line-up of topics and speakers to suit all tastes, and especially space exploration. One of the headline presentations will be ‘We will be Martians: Our Future on the Red Planet,’ with a top-flight range of speakers including: Professor Brian Greene, renowned physicist and World Science Festival co-founder; Yvonne Cagle, Chief Scientist, Level II Program Office Commercial Re-useable Suborbital Research program at NASA; Christin Charles, Professor and Head of Space Plasma, Power and Propulsion…

CELESTIAL BAUBLE Kevin Osborn Sharpless 2-308, also known as the Gourd Nebula, is a 60-light-year-wide bubble blown by a hot stellar wind from the bright star in the middle. The wind is shaping gas released thousands of years earlier. Kevin used a Sky-Watcher Esprit 100 ED telescope on a Sky-Watcher EQ6-R Pro mount. The camera used was a ZWO ASI1600MM Pro with red, green, blue, H-alpha and OIII filters. RINGED WONDER Michael Clark Saturn was high in the sky in August 2018 when Michael used his Sky-Watcher Newtonian OTA, Sky-Watcher EQ6 mount and AstroShop GSTAR-EX3 colour video camera to produce this image. It’s a stack of the best 5% of 1,554 frames. STARGAZERS Michael Mattiazzo The Milky Way hugged the horizon as observers gathered for the VicSouth Star Party at…

AFTER A NINE-YEAR historic mission, the Kepler space telescope has finished its job. Exhausted of fuel and hobbled with inoperative reaction wheels, Kepler’s exoplanet hunting days are over. “As NASA’s first planet-hunting mission, Kepler has wildly exceeded all our expectations and paved the way for our exploration and search for life in the Solar System and beyond,” said Thomas Zurbuchen (NASA) in an October 30th press release. Launched on March 6, 2009, Kepler took up station in an Earth-trailing heliocentric orbit. The telescope’s initial mission was to stare at a patch of sky overlapping the constellations Lyra, Draco and Cygnus, looking for rhythmic dips in starlight that betray the presence of transiting planets as they passed in front of their suns. To this end, Kepler monitored about 150,000 stars during…

ASTRONOMY 2019 YEARBOOK Every astronomer needs the Astronomy 2019 yearbook. Australian-produced, it is packed full of essential information to plan your observing sessions. Included is a complete guide to what’s visible in the night sky, including Moon phases, planets, comets, eclipses and meteor showers, plus star maps and a month-by-month viewing guide. $29.95 plus postage & handling 2019 AUSTRALASIAN SKY GUIDE An ideal yearbook for beginners, the easy-to-read 2019 Australasian Sky Guide provides a month-by-month guide to what can be seen with the naked eye, along with lots of interesting facts and figures, detailed descriptions of special astronomical events, and planetary data. $16.95 plus postage & handling ASTRONOMY 2019 CALENDAR Featuring amazing celestial photography from the annual David Malin Awards, the Astronomy 2019 Calendar provides a guide to…

CAROLINE HERSCHEL is probably the most famous female astronomer of the early modern era. In 1772, her celebrated brother William, discoverer of Uranus, brought her to England, where she helped him in his activities, first as a singer and then as an astronomer. Although this little woman (a disease in her youth limited her growth to about 4 feet 3 inches) had to work under the supervision of her renowned brother, she was gradually able to pursue an independent astronomical career sprinkled with several important successes. She discovered 14 deep sky objects, including galaxies and open clusters that William later included in his catalogue, as well as eight comets; the first of these comets, discovered on the night of August 1, 1786, is now designated C/1786 P1 Herschel. In the…

WHEN Late January 1 a.m. Early February Midnight Late February 11 p.m. Early March 10 p.m. These are daylight saving times. Subtract one hour if daylight saving is not applicable. HOW: Go outside within an hour or so of a time listed above. Hold the map out in front of you and turn it around so the label for the direction you’re facing (such as west or northeast) is right-side up. The curved edge represents the horizon, and the stars above it on the map now match the stars in front of you in the sky. The centre of the map is the zenith, the point in the sky directly overhead. FOR EXAMPLE: Turn the map around so the label “Facing NE” is right-side up. About halfway from there to…

I’M A FAN OF Sky-Watcher’s Star Adventurer mount, a small, portable sky-tracker designed primarily for use with DSLR cameras and lenses. For its stated purpose, it works great. But some of the advertising shows it with a small telescope attached, and I’ve found this configuration to be less than optimal. Immersed in the world of large mounts and high-end imaging, I often find myself yearning for a small Go To mount that can hold a small telescope for visual use but is also small enough to fit in airline carry-on compartments. Enter the Sky-Watcher AZ-GTi mount. It’s small and lightweight, weighing just 4 kg including its surprisingly sturdy tripod. The mount runs on 12 volts DC and can be powered by eight AA batteries housed in the mount body or…

WA Astrofest March 16 A family friendly astronomy festival held in Perth. astronomywa.net.au World Science Festival Brisbane March 20–24 Multiple activities, including a headline Mars presentation. worldsciencefestival.com.au Earth Hour Open Night March 30 Free family stargazing event with Sydney’s Sutherland Astronomical Society. sasi.net.au Yuri’s Night April 12 Annual worldwide celebration of space on the anniversary of Yuri Gagarin’s flight. yurisnight.net South Pacific Star Party May 2–5 Annual star party of the Astronomical Society of NSW. asnsw.com/spsp RASNZ Conference May 17–19 New Zealand’s annual astro gathering, this year to be held in New Plymouth. rasnz.org.nz/32-conference Asteroid Day June 30 A global day of education to help protect Earth from asteroids. asteroidday.org National Science Week August 10–18 Includes lots of astro events. Keep visiting the website for the latest info. scienceweek.net.au Astro…

LAST YEAR, A TSUNAMI of gravitational waves washed over Earth, heralding the ancient collision of two neutron stars in a far-off galaxy. Such collisions appear to be the birthplace of many of the heaviest elements such as gold, platinum and uranium. Now an unusual, rapidly brightening supernova might help researchers understand just how such neutron star duos arise in the first place. The supernova, designated iPTF14gqr, went off in the outskirts of a galaxy some 900 million light-years away. Detected in October 2014, this supernova seemed odd right away. Most supernovae take a few weeks to hit their peak brightness. This one did so in less than 7 days, suggesting it had only a relative paucity of debris to clear out of the way. Kishalay De (Caltech) and colleagues estimate…

SHORT ON FUEL, the end has come for NASA’s Dawn spacecraft, the first and only mission to visit the dwarf planet Ceres and the asteroid Vesta. It was the first mission to orbit more than one body beyond Earth and the Moon. It was NASA’s first deep space mission to use ion propulsion. And Dawn was also the first spacecraft to visit a dwarf planet, beating the New Horizons flyby of Pluto by just a few months. Launched in 2007, Dawn eventually arrived at asteroid 4 Vesta on July 16, 2011. Dawn revealed the misshapen world in dramatic detail, mapping it from pole to pole while probing it from core to surface. One key finding was that Vesta seems to be a remnant of the rocky planetesimals from the early…

The Large Magellanic Cloud (LMC) is one of the many splendid sights of our southern sky, even though you need a dark sky to see it best. A small galaxy lying not far from the South Pole of the sky, it appear as a faint, fuzzy patch of light to the naked eye. The LMC is a neighbour of our own galaxy, the Milky Way, and sits some 168,000 light years from Earth. If you’d been lucky enough to be looking towards the LMC at the right moment on February 23, 1987, you would have noticed something new — a sudden brightening that outshone all the other stars in the vicinity. You would have been seeing the first supernova bright enough to be visible to the naked eye since the…

If history had turned out a little differently, Todd Henry might have become a leading light in the search for extraterrestrial intelligence. Instead, for the last quarter of a century he’s been leading the charge to learn all that we can about the nearest stars. Henry graduated from Cornell University in the 1980s, where one of his advisors had been none other than Carl Sagan. With such inspiration, it’s little surprise that after completing his PhD he opted to join NASA’s SETI project, which was to be a huge 10-year quest to search for signals from extraterrestrial civilisations. Yet just a year after observations began, the rug was pulled out from under the project as Congress cancelled its funding. Still, the questions that SETI posed remained with Henry. If life…

FEBRUARY 1 Venus and Moon very close 2 Saturn 6° south of Moon 10 Mars 8° north of Moon 10 Uranus 9° north of Moon 14 Uranus 1° south of Mars 14 Aldebaran 1.5° south of Moon 17 Pollux 7° north of Moon 18 Saturn 1° south of Venus 19 Regulus 3° south of Moon 26 Antares 8° south of Moon 27 Mercury, greatest elong. (18° east) 27 Jupiter 2° south of Moon MARCH 2 Saturn 0.5° south of Moon 3 Venus 1° north of Moon 10 Uranus 4° north of Moon 11 Mars 6° north of Moon 13 Aldebaran 2° south of Moon 15 Mercuy at inferior conjunction 16 Pollus 7° north of Moon 19 Regulus 8° south of Moon 21 Equinox 22 Spica 8° south of Moon 26…