Innholdsfortegnelse for May/June 2019 i Australian Sky & Telescope

ONE OF THE JOYS OF ASTRONOMY is that the non-professional has always had an opportunity to take part in scientific research. From the days of the self-funded ‘gentleman astronomer’ to the era of coordinated amateur observing programs run by the likes of the AAVSO, BAA, IMO, RAZNZ and so on (look them up!), the everyday non-professionally trained person has been able to find their niche. In this digital era, however, it has reached the stage where you don’t even need a telescope — or to have ever looked through one — in order to take part in serious research programs. Citizen science, it is called. There are numerous fascinating scientific programs in which you can participate that require nothing more than a computer, Internet connection and a few hours of…

THE UNIVERSITY OF SOUTHERN Queensland’s (USQ) Mount Kent Observatory is being expanded to help it continue its astronomical work, including in the hunt for exoplanets. Once the expansion is complete, the expanded $6 million facility will have a total of 13 telescopes and other new technology to enable researchers and students to be at the forefront of ongoing planet discovery work — including NASA’s Transiting Exoplanet Survey Satellite (TESS), in which USQ is playing a leading role. At the launch of the facility upgrade on March 20, USQ Vice-Chancellor Professor Geraldine Mackenzie noted that “USQ astrophysicists have contributed to the discovery of more than 100 exoplanets, with more than 30 alone in the past 12 months. Just this week the team has detected two more new exoplanets from the NASA…

ASTRONOMERS AT THE WINTER have proposed contrasting scenarios to explain a strange celestial blast spotted last year. Did a medium-mass black hole tear a white dwarf apart, or are we seeing a new type of supernova? The robotic Asteroid Terrestrial-impact Last Alert System (ATLAS) survey picked up the event on June 16, 2018, and automatically designated it AT2018cow, but astronomers quickly dubbed it ‘The Cow’. The flash, which appeared in a spiral arm of a star-forming galaxy 200 million light-years away, took only two days to climb to a peak luminosity of 100 billion Suns — at least 10 times brighter than a typical supernova. Even stranger, the explosion’s aftermath showed only the chemical fingerprints of hydrogen and helium, rather than the heavier elements characteristic of ‘ordinary’ supernovae. And follow-up…

Spirals are the most spectacular of galaxies. Like a giant vortex in space, a spiral galaxy spins through the cosmos, its mighty arms squeezing gas and dust into newborn stars. Blue supergiant stars and pink clouds of ionised hydrogen gas sparkle in the spiral arms, where the occasional flash of a supernova explosion casts newly minted chemical elements into the galaxy. These magnificent galaxies lend grace and beauty to the night. Moreover, they work hard to create new light. Five out of every six stars born each year are born in spiral galaxies, some in normal spirals like the Whirlpool, others in barred spirals like the Milky Way. Yet these same exquisite galaxies face an immense problem. As spiral galaxies spawn new suns, they exhaust the very gas and dust…

WHEN Late April 11pm Early May 10pm Late May 9pm Early June 8pm Late June 7pm These are standard times. 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 so the label “Facing SW” is right-side up. About a third of the way from there to the map’s centre is the brilliant star…

This issue’s target is S Virginis, a well observed Mira-type variable currently around maximum light (it varies from magnitude 6.3 to 13.2). The data set for this star comprises some 20,000 observations spaning 165 years, logged by 420 observers. This degree of cooperation doesn’t happen by accident — it takes motivation and coordination. John Herschel helped start variable star observing as we know it today. In 1833 he singled out the pursuit as an important endeavour best done by amateurs; the professional astronomer has too much else to do. This sentiment is just as true today, even in these times of automated sky surveys. S Vir was identified as variable in 1852, by which time the need for observers was on the way to being satisfied. Observation of S Vir…

IN MARCH, AUSTRALIA’S CHIEF Scientist, Dr Alan Finkel opened new facilities at the Astronomical Society of Victoria’s (ASV) dark sky site near the town of Heathcote in central Victoria. He was joined by around 400 ASV members, visitors and distinguished guests. The opening was a very informal affair with Dr Finkel casually, but appropriately, dressed for the very warm afternoon, and accompanied by his wife Elizabeth and their adult children. The new facilities included a new 1.0-metre Dobsonianmounted telescope, housed in a new, rectangular roll-off roof observatory, and an impressive radio telescope facility with an 8.5-metre-diameter, steerable dish. Other improvements include two new accommodation blocks (eight rooms with a total of 32 beds) and an ablutions’ block with showers and septic toilets. Beginning his opening speech Dr Finkel searched his…

WHEN JACK FRILLMAN was preparing to watch the August 2017 total solar eclipse, he knew he didn’t want to waste precious totality time fussing with camera gear. So he designed and built a camera controller that would automate the entire process of photographing the event. Centred around a Raspberry Pi computer and using a custom-made circuit board to drive the camera, it worked so well that when he got home he modified it so he could use it for his night-time astrophotography, too. There are many commercial packages available for controlling cameras, but Jack’s system has the advantage of being small, light, easy to program and inexpensive (about $210 for the works). Jack built the controller to work with his Pentax K20D DSLR, but it should work with any camera…

RECENTLY, A HIGH SCHOOL STUDENT emailed the observatory at which I work, asking why someone would want to become an amateur astronomer. Eventually, it reached my desk. In his note, he asked for at least two reasons. I gave him six. First, just going outside and savouring the night. In addition to the beauty of the sky, you might hear many sounds of nature not present during the day, such as the chirp of crickets or the cry of a bird declaring its territory. Also, for many the night air has a cleaner, fresher scent of its own. Looking up, you are immediately gazing back in time. You’re seeing planets and stars as they appeared from just a few minutes to possibly thousands of years ago. The constellation patterns are…

A bevy of fast radio bursts announced A new radio array, the Canadian Hydrogen Intensity Mapping Experiment (CHIME), has spotted 13 new fast radio bursts (FRBs) — including the second one known to repeat. These mysterious flashes probably occur thousands of times per day, but they’re so fleeting that astronomers miss most of them. The new FRBs were detected over a period of about three weeks last year, when CHIME was running at only a fraction of its full capacity. The highlight of the bounty is a single burst that flared time and again. Reported in the January 9 issue of Nature and announced at the winter meeting of the American Astronomical Society, the repeating burst was first detected on August 14, and then CHIME saw it pop up five…

Before we get going, let’s review a few things about the orbital plots and what you might see in the sky. Don’t expect the binary components to be moving as you observe! The most rapid binary pair discussed here completes its orbit in 50 years. Still, the relative positions of three binaries in this article — Sirius, Gamma Virginis and 70 Ophiuchi — change enough in 10 years for a visual observer to confirm orbital motion. It’s an exhilarating experience. Presented here are apparent orbits where the secondary component, B, is shown revolving around a fixed primary, A (as is customary). The orbit is projected ‘flat’ onto the celestial sphere. For the plots, I’ve scaled the components’ magnitudes and coloured them according to their spectral types. Also included is the…

Carl Sagan once wrote of the Earth surrounded by space as “a meadow in the middle of the sky”. I’ve written in this column previously about a different “meadow in the middle of the sky”. The meadow in question is the section of heavens bounded by the main patterns of the Big Dipper, Boötes, Virgo and the hindquarters of Leo. It can be found above the norther horizon on May evenings for observers at mid-southern latitudes. It contains the constellations Coma Berenices and Canes Venatici and the central region of the Virgo Galaxy Cluster. It’s bounded by mostly rather bright stars but is itself sparse of naked-eye stars —and superbly rich with fuzzy, intricate, relatively bright galaxies for amateur telescopes. Revisiting the meadow in the sky. In May, when Earth’s…

MAY 2 Venus 4° north of Moon 3 Mercury 3° north of Moon 7 Aldebaran 2° south of Moon 7 Mars 3° north of Moon 10 Venus greatest latitude south 10 Pollux 6° north of Moon 12 Regulus 5° south of Moon 16 Spica 8° south of Moon 20 Antares 8° south of Moon 21 Jupiter 1.5° south of Moon 21 Mercury at superior conjunction 23 Saturn 2° east of Moon 31 Uranus 5° north of Moon JUNE 2 Venus 3° north of Moon 5 Mercury 4° north of Moon 5 Mars 5° east of Moon 6 Pollux 6° north of Moon 8 Regulus 9° east of Moon 11 Jupiter at opposition 12 Spica 8° south of Moon 16 Antares 8° south of Moon 17 Jupiter 2° south of Moon…

It’s a funny position to be in, that of observing a galaxy that I’ve seen countless times and yet seeing it for the first time in a new light. With apologies to Arthur Schopenhauer, I like to think “the task is not to see what has never been seen before, it’s instead to think what nobody has yet thought about that which everyone sees”. After observing many extraordinarily faint objects with my new 33-cm f/3.0 high-etendue richest-field telescope, under the stars one gloriously clear and transparent night I thought to ‘go for broke’ and try observing the galactic cirrus near M81 and M82. To my astonishment, upon centring the galaxies, I could detect faint nebulosity crisscrossing the field of view. It was an extraordinary moment — like stepping through a…

In our first installment of this series, we talked about keeping your Newtonian telescope clean and how to wash the primary mirror when it gets dirty. Now let’s look at how to collimate it. Like mirror washing, collimation is a lot easier than many people think. The Internet is so full of scary advice on collimation that many people think it’s as dangerous as choosing whether to cut the red wire or the green wire when defusing a bomb, but it’s really pretty simple. Collimation means lining the mirrors up in a straight line. The primary mirror needs to be pointing more or less straight out of the tube, the secondary mirror needs to be more or less centred over the primary, and it needs to bounce incoming light down…

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 Occultation Symposium May 20–21 For serious occultation observers and researchers. rasnz.org.nz 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 Rocks Fest September 20–22 Family weekend of both astro and geo fun at Mt Magnet, WA. mtmagnet-astrorocks.com International Observe the Moon Night October 5 Annual event to encourage observation and understanding of our Moon. facebook.com/observethemoon/ NZ Starlight Conference October 20–23 The theme is ‘Towards a Dark Sky Nation’. starlightconference.org…

BARNARD 33 Franco Rodriguez Better known as the Horsehead Nebula, Barnard 33 is a dark nebula located in Orion. It was first spotted in 1888 by Williamina Fleming on a photographic plate taken at the Harvard College Observatory. For this shot, Franco used a Sky-Watcher Esprit 100-mm triplet refractor and both ZWO ASI071MC and Starlight Xpress Trius SX814 cameras. THERE BE DRAGONS Rodney Watters NGC 6188 is informally known as the ‘Dragons of Ara,’ so-called because of its resemblance to dragons and the constellation in which it lies. Rodney used a Takahashi TSA120 OTA at f/5.6, CSI683 WS8 camera and Ha, OIII and SII filters for multiple sub-frames, with a total exposure time of 28.7 hours! BUBBLE AMONG THE STARS Dave Manning Open star cluster Messier 46 is pretty enough,…

ASTRONOMERS HAVE FOUND a way to use quasars to measure the evolution of dark energy, the repulsive pressure that accelerates our universe’s expansion. The results, which appeared January 28 in Nature Astronomy, have potentially far-reaching implications for cosmology. Cosmology is based on accurate gauges of distance, and detonating white dwarfs known as Type Ia supernovae have long been the standard candle of choice. Their intrinsic luminosities are known, so their distances are, too. With these objects astronomers have probed the universe at a time when dark energy began to dominate its expansion. To see even earlier times, before dark energy took over, Guido Risaliti (University of Florence, Italy) and Elisabeta Lusso (Durham University, UK) turned to quasars, gas-guzzling supermassive black holes that are brilliant enough to be seen when the…

Mercury (mag. –0.9, dia. 5.3” in mid-May) begins May low in the eastern, morning sky, before being lost in the solar glare as it heads for superior conjunction (ie. on the other side of the Sun) on May 21. Look for Venus and the 27-day-old thin crescent Moon nearby on May 3. Returning to the western, evening sky in June, the innermost planet will have a very close conjunction with Mars on the 18th, with the separation between the two planets reducing to just 0.4°. Take a look about an hour after sunset (see diagram on the next page). Venus (–3.8, 11”) remains a bright beacon in the eastern, morning sky, very slowly losing altitude and moving sunwards in the brightening dawn light as it heads towards superior conjunction in…

Although Ceres lacks a permanent atmosphere, astronomers have detected an exosphere, a thin layer of water vapour enshrouding the asteroid. But the water signatures appear to be variable rather than permanent, sometimes detectable, sometimes not. Early hypotheses posited impact activity, localised geysers and/or sublimation (the transformation of solid ice to gas) as possible sources of the vapour. Any of these causes could be linked to the exosphere’s variability as well. Planetary geologists are confident that sublimation, triggered by heating when Ceres approaches the Sun, is probably the original or even an ongoing source for water vapour. But sublimation can’t account for it all, particularly because vapour has been detected when Ceres was at an orbital location away from the Sun. When NASA’s Dawn spacecraft arrived at Ceres in March 2015,…

My fascination with billion-light-year galaxies began nearly 40 years ago when I read about the fabulously rich and distant Corona Borealis Cluster (Abell 2065) in Burnham’s Celestial Handbook. The cluster features several hundred elliptical (E) and lenticular (S0) galaxies packed into a 30’ circle, the size of the full Moon. Due to the remoteness of the cluster, its brightest members are quite dim — close to 16th magnitude — and Robert Burnham, Jr. warned they were “far beyond the reach of the usual amateur telescope”. This was a fair assessment back in the 1970s. But a few years later I netted seven elusive fuzzies using my 45-cm reflector — after considerable effort. All were featureless glows, but the largest was 15.4-magnitude PGC 54876 — a 15” smudge just 1.4’ east…

There are plenty of activities planned for the 50th anniversary of the lunar landing of Apollo 11, around Australia and around the world. Here are some of the major local events you can look forward to. In Brisbane, the NASA – A Human Adventure exhibition has opened at the Queensland Museum. Spanning two levels, this is the largest exhibition ever staged at the Museum. More than 250 items are on display, including original artefacts that have flown in space, rocket engines, a collection of space suits, and full-scale replicas of the front section of the space shuttle, a lunar rover, Mercury, Gemini and Apollo capsules and the Soviet robotic lunar rover, Lunokhod. Full details at qm.qld. gov.au/space. On July 20 and 21, the CSIRO’s Parkes Observatory will throw open its…