Innholdsfortegnelse for October 2018 i Australian Sky & Telescope

ASTRONOMERS HAVE DISCOVERED a pulsar that comes with its own magnifying glass — courtesy of its brown dwarf companion that’s being torn to shreds. The pulsar PSR B1957+20 and the brown dwarf are dancing a cosmic dervish in an eclipsing binary system 6,500 light-years away. During every 9.2-hour orbit, the brown dwarf eclipses the pulsar for about 50 minutes. Their dance won’t last — in addition to its lighthouse-like beam of radio waves, the so-called ‘black widow’ pulsar releases a fierce wind of energetic particles that’s slowly blasting away its companion. But before the brown dwarf fully disintegrates, its cocoon of plasma acts like a magnifying glass that resolves two areas of emission on the pulsar only 20 km apart. Although astronomers have seen plasma lensing before, it wasn’t obvious…

Thanks to the relative ease of getting to the path of totality last year, citizen scientists played a key and arguably powerful role. Some teams studied the Sun’s corona and chromosphere, while others monitored the response of Earth’s ionosphere and neutral atmosphere to the rapidly changing incidence of sunlight. The Citizen CATE (Continental-America Telescopic Eclipse) project extended the idea of multiple observations to the max. A team led by Matt Penn (then at National Solar Observatory) brought together amateurs and professionals to operate 68 nearly identical setups strung along the eclipse path from Oregon to South Carolina. The resulting images from 61 successful stations are being combined to yield an 82-minute-long record of the corona’s appearance and its evolution. Challenges still remain in combining and analysing these thousands of images,…

You’ve probably seen a ‘falling star’ or two in your lifetime: brilliant flashes of light zipping across the night sky. These luminous streaks aren’t really ‘falling’ or ‘shooting’ stars, of course, but meteors (from the Greek meteoros, which means ‘high in the air’). Meteors occur when interplanetary debris called meteoroids enter Earth’s upper atmosphere. From the length and vibrancy of the resultant light streak, you’d think most meteoroids are tremendously large, but they’re usually no bigger (and often significantly smaller) than aquarium pebbles. These tiny bits strike our atmosphere at high velocities — from 40,000 to over 240,000 kph — ablating rock grains and exciting particles such that they emit light and colour. Most meteors consist of ice and dust, so when they hit Earth’s atmosphere, they disintegrate in a…

The Minor Planet Center announces dozens of new Solar System discoveries every week. Most notices are mundane, describing the orbits, appearances and sky locations of unremarkable, newly detected comets and asteroids. But on October 25, 2017, the MPC’s Electronic Circular 2017-U181 reported the discovery of a singular outsider: a faint object rushing through the inner Solar System that, based on its trajectory, was making a one-time visit from the stars. Postdoc Robert Weryk (University of Hawai‘i, Ma¯noa) had made the discovery a week earlier on October 19, while looking for near-Earth objects with the aid of the 1.8-metre Pan-STARRS 1 scope. This robotically controlled telescope of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) program sits near the summit of the Haleakala¯ volcano on Maui. Its primary charge is…

Capricornus is certainly not a very bright constellation, nor one with a lot of notable deep sky objects within its bounds. Even so, I find it more fascinating and more of a standout than many other constellations, even some others of the zodiac. Why do I find it so compelling? First of all, no other constellation represents something so peculiar — a creature half-goat and half-fish. Yet its strange goat-fish form is also the key to directly identifying it as one of the most ancient of all constellations. Other notable attributes of Capricornus include its compactness, its rich connections with language, its remarkable double stars, and its position with regard to the zodiac and certain deep sky objects. Capricornus, the compact standout. At this time of year, Capricornus is almost…

Telescopium, the Telescope, is a southern constellation created in 1752 by the French astronomer Lacaille. Its western part, where its brighter stars are found, sits just south of Corona Australis. The first of our doubles is HJ 5033, nearly two degrees northeast from 3.7-magnitude Theta Arae. This bright orange star has two obvious, 10th-magnitude, fairly wide companions (B and D), and a third (C) much fainter, in a quite starry field. All three companions were visible with an 18-cm aperture at 100×. Small scope observers may find the 12th-magnitude C companion is too faint. North from HJ 5033, another John Herschel discovery, HJ 5034, is placed between Epsilon Tel and Alpha Tel. With 18cm at 100× this one was a beautiful, somewhat unequal close pair, moderately bright and in a…

Having scouted out a location the day before, Renato Langersek took this shot of the eclipsed Moon and Mars hanging over the skyline of Brisbane. He used a Canon EOS 5D Mark II camera and a Canon 70–200-mm zoom lens at 70 mm for the 2-second image.…

Although the awful drought continues across NSW, astronomers are quietly enjoying an extended run of clear, cloudless nights. The weather has made this year’s Milky Way season one of the best in memory for astrophotographers. The clear climate, combined with a stellar line-up of astronomical talent, contributed to the Star Stuff II astrofest (held at the Elements of Byron resort in Byron Bay, NSW) being a huge success, with many attendees saying it may even have outdone last year’s inaugural event. There were 12 high-profile speakers, including international guests Amy Shira Teitel, Fraser Cain and Geoffrey Notkin. The guests and other attendees all were treated to especially clear, dark views of the southern night skies from the resort’s location near the easternmost point of Australia’s coastline. Members of the Southern…

ON JULY 17, the International Astronomical Union’s Minor Planet Center announced that a search team led by Scott Sheppard (Carnegie Institution for Science) has identified 10 new moons of Jupiter, bringing the known total to 79 — the most of any planet in our Solar System. Of that total, Sheppard has led the searches that discovered 51 of them. Dozens of Jupiter’s moons circle the planet in a retrograde direction, that is, opposite that of the planet’s spin, in a swarm of distant orbits. They cluster in three groups of 15 to 20 objects, named for members Ananke (discovered in 1951), Carme (1938) and Pasiphae (1908). Most likely each of these moonlet ‘families’ represents fragments of larger precursors that were shattered by collisions early in Jupiter’s history. Of the 10…

SCIENTISTS HAVE ESTABLISHED that 3 billion years ago, a supervolcano created one of the largest rock deposits on Mars, the Medusae Fossae Formation (MFF), which spans an area equivalent to one-fourth of the size of Australia. Scientists have been probing the nature of the massive formation since the 1960s. Using orbiter radar, they recently narrowed its composition down to two main possibilities: porous rock or kilometres-thick ice covered by ash. Now, scientists have used gravity data from Mars orbiters to resolve the conflict, using the formation’s gravitational pull on the satellites to infer its mass and density. Combining this information with the radar data enabled researchers to rule out ice as MFF’s main ingredient, leaving porous rock as the viable candidate. When a volcano explodes, explains lead author Lujendra Ojha…

Which happenings in astronomy can we celebrate on October the 4th? Space watchers will recall at least one significant event; the launch in 1957 of the USSR’s Sputnik 1 satellite, the first artificial object to orbit the Earth. That was at the dawn of the space enterprise, which over the 60 years since has led to many achievements, including the launch of the Hubble Space Telescope in 1990. There is something that links October 4 and Hubble, or at least Edwin Hubble, the eminent US astronomer after whom the space observatory is named. On that day in 1923, Hubble used the biggest telescope of the time — the just-completed 2.5-metre-diameter Hooker Telescope at Mount Wilson outside Los Angeles — to take the first of a series of photographs of a…

“There is orange soil! It’s all over! Orange!” Harrison Schmitt’s excitement crackled over Apollo 17’s radio. His companion, surrounded by the grey lunar landscape, wondered if Schmitt had been on the Moon too long. He came to take a look. “Hey, he’s not going out of his wits,” Eugene Cernan chimed in, seeing the material Schmitt’s footsteps had uncovered and catching his excitement. “It really is.” Schmitt, a geologist and the first scientist-astronaut to set foot on our planet’s natural satellite, knew he was seeing something important. The two astronauts hurried to dig a trench, snap images, and collect samples. Further analysis on Earth later revealed that the orange soil was 3.7 billion years old and had formed during a volcanic eruption. The orange soil wasn’t the only thing worth…

A drum that I happily bang in my public talks is that if you want to understand the large-scale structure of our galaxy, binoculars are often more useful than a telescope. The vast dust lanes and star clouds that spangle the Milky Way through Scorpius, Sagittarius and beyond, are mostly too big to appreciate through all but the richest-field telescopes. The Scutum Star Cloud is a prime example. Neatly framed between Beta (β) Scuti and Epsilon (ε) Scuti, the densest part of the cloud is about 3.5° across. A lot of small scopes will show that much, but to fully appreciate the Scutum Star Cloud you need to take in more sky. To the southeast, the star cloud fades gently into the rich star fields of the Milky Way. But…

In the northern half of our spring sky can be found the Great Square of Pegasus, which you’ll find cozied up to the meridian on this month’s all-sky map (pages 42-43). As Garrett P. Serviss writes in his ever charming book Astronomy with an Opera-Glass, the Great Square “at once attracts the eye, there being few stars visible within the quadrilateral, and no large ones in the immediate neighbourhood to distract attention from it”. The Great Square contains a handful of galaxies, little-known to most amateur astronomers. Let’s round up a few of those that are a bit of a challenge for medium-sized telescopes. We’ll start with one of the easier catches, NGC 7678, which is found 1.2° west of the pulsating red giant star 71 Pegasi (magnitude 5.3 to…

It’s no secret that spectacular astrophotography can serve as an entry point into the hobby of amateur astronomy. Whether it’s a high-resolution image from the Hubble Space Telescope, an iPhone photo of lunar craters or a long-exposure nightscape, a photograph can capture the imagination or encourage us to ask questions about our universe. New observers often want to capture the view through the eyepiece but find the astrophotography learning curve a bit steep. Some imaging equipment can be expensive and complex, and even with the right equipment the results can be perplexing. How to even get started? To help you out, I’ve gathered some of my best advice here in the form of a ‘Top 10’ list specifically aimed at novice imagers. 1: No expensive equipment needed The minimum requirements…

It is no surprise that the CCD’s best performance is with a single long exposure. What may be surprising is the Kepler KL4040 CMOS camera has a better signal-to-noise ratio than the PL16803 even with a single long exposure. The signal-to-noise ratio of the KL4040 is better than the PL16803 even when using short exposures that are stacked! The benefit of taking multiple short exposures is the option to discard a bad exposure ruined by satellite trails, tracking errors, or bad seeing (etc.). Incredible low-noise images are now possible with a single long exposure or many stacked short exposures. The KL4040’s superior performance allows it to be used for a wide range of applications and requirements. At Finger Lakes Instrumentation, we design and build unrivaled CMOS and CCD cameras, filter…

NASA’S CASSINI made Enceladus, one of Saturn’s icy moons, famous for its plumes of salty, organics-laced water-ice crystals. Now, a closer analysis of data from two spectrometers aboard the spacecraft reveals that the carbon-based brew inside Enceladus must be more massive and complex than previously realised. Scientists had used Cassini’s Ion and Neutral Mass Spectrometer, which can only measure up to 100 atomic mass units, to detect relatively simple organic compounds. For example, methane (CH4 ) has an atomic mass of 16 amu. But in this new study, published in the June 28 issue of the journal Nature, data from the spacecraft’s Cosmic Dust Analyzer (CDA) revealed that Enceladus’s organic complexity extends up to thousands of atomic mass units. Moreover, the CDA researchers, led by Frank Postberg (Heidelberg University, Germany)…

The rarity of the event allowed for unprecedented science, including first-time observations of phenomena predicted for more than 50 years. Last year’s total solar eclipse was an amazing spectacle. Such events aren’t rare in a global sense — they happen about every 18 months somewhere on Earth. Last year the Moon’s shadow raced coast to coast across the continental United States and thus touched a swath of populated, accessible land 4,000 km long. Tens of millions of people witnessed totality on August 21, 2017, and an estimated 100 million saw the Sun partly covered, making it one of the most observed solar eclipses ever. The rarity of that day’s event also allowed for unprecedented science. Besides studying the Sun’s outer atmosphere during totality, many researchers also looked at the rich…

This year the Orionid meteor shower’s peak will be badly affected by the light of a near full Moon, but with increased activity predicted it will still be worth having a look. From 2006 to 2009 the shower produced unexpectedly strong zenithal hourly rates (ZHRs) of around 40 to 70. A 12-year periodicity due to Jupiter’s gravitational influence has now been confirmed, and rates are expected continue to increase in the next few years. This year, the predicted ZHR is 22 to 28, but due to the presence of the moonlight you might see only see 6 to 8 meteors from a dark sky location. The Orionids often produce several lesser maxima, serving to keep activity fairly constant for several consecutive nights before and after the peak on the morning…

This spring marks the return of the gas giants Uranus and Neptune (although many people call them ice giants) to the evening sky, at least for the foreseeable future. Neptune arrives at opposition on September 7, Uranus on October 23, so we’ve reached the ideal part of the calendar for observing them. During the next few months, Uranus will be in the southwest corner of Aries (it will visit Pisces in December and January) while Neptune will be in Aquarius. The charts here show their positions south and east-southeast of the Great Square of Pegasus. If you poll people at your next star party, you may discover that many will have seen Uranus, but few might have seen Neptune. Uranus is a much easier target. It’s a late-night object in…

RSpec Real-Time Spectroscopy US price: $109 RSpec-astro.com What We Like Remarkably effective for both capturing and analysing spectra Works with inexpensive diffraction grating Intuitive What We Don’t Like Lacks a printed manual Sensitive to camera driver problems FOR ME, ASTRONOMY COMES IN two parts. A portion of my time is spent as an astronomy educator, teaching the science of the universe. But I’m also an amateur astronomer, and in that aspect I’ve mostly confined myself to observing pretty stuff. Occasionally, however, I long to put a little more science into my amateur astronomy. I’ve found just the thing for that, a clever software program called RSpec. As you may have guessed from its name, RSpec is concerned with spectroscopy. This software, combined with a simple diffraction grating and a digital…

NEARLY EVERYONE with a telescope also has a neighbour with unshielded outside lights. Even if they’re good and keep the lights off when they’re not actually using them, their interior lights still leave brightly lit windows. Plus, if you observe from your driveway there are car headlights, street lights and the person walking their dog with an aircraft landing light for a headlamp. Ken Martin has come up with a solution: multiple panels of light-blocking material that he can place in whatever arrangement is necessary. The construction is simple, straightforward and relatively inexpensive, yet lightweight, durable and easy to use. Ken used ¾-inch, lightweight, thin-walled PVC pipe for the framework. A handful of Ts and elbows connect the sections into rectangles, and wide-head screws hold the fabric to the pipe.…

I hadn’t realised I was stepping into a trap. I was feeling good about myself, but being the brilliant strategist she is, Sue had me right where she wanted me. ASIDE FROM THE ESSENTIALS of life, few things in this world seem to interest everybody. Astronomy happens to be one of those universal passions, one that unites people of all cultures. My own level of fascination has always been high. At 9 years old, I watched Neil Armstrong’s “small step,” and since then astronomy’s been inside my head . . . in more ways than one. My wife Sue, on the other hand, is like most people: curious, but not enough to take it to the next level. Which is why I gave up on encouraging her years ago. Until…