Innholdsfortegnelse for September - October 2022 i Australian Sky & Telescope

SPECTRUM THE WAIT IS FINALLY OVER. Less than seven months after launch and a journey of almost two million kilometres, the James Webb Space Telescope’s multi-decade voyage of exploration has begun with the release of its first science images. If they seem a little familiar, that’s because they’re of objects we’ve all seen many times before. But that’’ precisely why they were chosen for this initial showcase — to enable us to compare earlier images and analyses with the kind of work that Webb can produce. And that’s because, for most purposes, Webb is far more powerful than anything that has come before it. In a sense, we’ve sort of become accustomed to amazing discoveries and images from space telescopes. It could even be said they’ve become a little ho-hum…

Astronomy as we know it today had its start in Europe around the start of the 17th century. The Greeks and the Muslims had made discoveries earlier, but they were shackled by a conviction that the Earth was the centre of the cosmos, and by a confusion between the roles of astronomy and astrology. Those ideas had persisted for moqe than a millennium. Those views began to fall part in 1543, when the Nicolaus Copernicus reluctantly published his view that the Sun, rather than the Earth, ruled our universe. A little later, Tycho Brahe found evidence that not all was unchanging beyond the orbit of the Moon, as prevailing wisdom maintained. Later again, Tycho’s assistant Johannes Kepler corrected Copernicus by showing the orbits of the planets were ellipses rather than…

VISUAL ASTRONOMY IN 1850, HARVARD COLLEGE OBSERVATORY astronomers William Cranch Bond and his son George Philips Bond discovered a new inner ring of Saturn. The feature was subsequently designated ring C, and British astronomer William Lassell dubbed it the crepe ring. The Bonds used the 38-cm refractor at Harvard for their discovery, while William Rutter Dawes in England employed a 16-cm refractor when he independently discovered the ring in 1850. Subsequently, observers found it quite easy to verify the diaphanous ring’s existence — Thomas William Webb even glimpsed traces of it through a 9.4-cm refractor. But if it was this easy to see, how could it have escaped detection for so long? Had it, as Webb suggested, somehow grown more luminous over time? Webb’s idea never seemed very plausible, given…

Ultimately, what SETI seeks is signals. So, what happens if we don’t find any? Do we give up? Stop funding SETI? Similar questions have arisen around other topics, such as dark matter. Ample indirect evidence suggests dark matter’s presence in galaxies and clusters, yet the lack of direct detections troubles many. Nevertheless, progress continues as scientists conduct increasingly sensitive searches — and in that respect, SETI is no different. In fact, the lack of a signal can be informative in and of itself, ruling out certain stellar systems or types of technosignatures. As just one example, the Breakthrough Listen team has searched 1,327 nearby stars for the type of radio signals our own civilisation can make — and found nothing. The survey eliminates the possibility of both an Earthdirected radio…

COSMIC RELIEF Shards of alien metal lie strewn about the crash site of a derelict contraption from another planet, the remains of an intricately machined saucer sent by a strange and distant civilization… Ours. In April, NASA’s Ingenuity helicopter, which is tagging along with the Perseverance rover, returned hauntingly surreal photographs of the rover’s own discarded backshell, the cover of its entry vehicle. As the rover descended to the Martian surface on February 18 of last year, the backshell was jettisoned and came to rest, largely intact but smashed around the edges, atop the shifting red sands. My first thought on seeing the image above was “Cool!” It’s still very hard to fly something to Mars, and now to finally fly something on Mars, not to mention use it to…

The Southern Taurids meteor shower is active from September 10 to November 10, with a peak on the morning of October 10. (It shouldn’t be confused with the Northern Taurids, which peaks on November 12). This year the shower will be affected by presence of the full Moon, which will drown out a lot of the fainter meteors. But there’s also the potential in 2022 for a ‘Taurid swarm,’ where a concentration of larger meteoroids results in brighter meteors and even fireballs. This happened previously in 2012 and 2016. In a normal year the rate is five meteors per hour, but fingers crossed that this year we’ll be treated to a lot more. The Orionids shower, active from October 2 to November 7, has a typical rate of about 20…

ALL-SKY MONITOR Starlight Xpress announces the Oculus PRO All-Sky Camera (£995). This self-contained sky-monitoring system is based around the super-sensitive ICX825AL Sony ExView II interline CCD, with a 1,392 × 1,040 array of 6.45-micron-square pixels. It comes with your choice of lenses — a 1.55-mm f/2 fisheye lens with a 180-degree field of view that sees your entire sky all the way to the horizon, or a 2.55-mm f/1.2 lens with a 150-degree field of view. The system is housed in a polycarbonate dome enclosure measuring 150 × 95 millimeters that can be mounted on a post. It includes a built-in dew detection and prevention system that only heats the clear dome without increasing thermal noise in the detector itself. The camera connects via a USB 2.0 Mini-B cable and…

ASTRONOMER’S WORKBENCH BACK IN OUR AUG/SEP 2019 ISSUE, I wrote about Frank Szczepanski’s unique approach to making a binocular telescope using only four mirrors instead of the traditional six. Frank has since reduced the number of mirrors required to two. Of course, that requires a set of objective lenses up front instead of primary mirrors in back, but there’s plenty of innovation in between. One of the biggest problems with any large binocular telescope is that the distance between the centres of the primary light-gathering elements — be they mirrors or lenses — is wider than the spacing between the observer’s eyes That means the light must be bounced off matching sets of mirrors to bring the optical axes closer together. A clever solution Except it doesn’t, really. With his…

SUPER SCOPE NASA HAS WOWED the collective minds of the astronomical community with the release of the James Webb Space Telescope’s first science images, revealed at a White House press conference on July 13 (Australian time). The deep field: Showing off the gravitationally lensing galaxy group SMACS 0723, Webb’s Near-Infrared Camera captured the image over a mere 12.5 hours of exposure. Located in the southern constellation Volans, this galaxy cluster existed 4.6 billion years ago, while other, ‘lensed’ galaxies far behind are older still. The galaxies in the cluster are generally white, while the more distant galaxies appear red and distorted. Among those background galaxies is one at a redshift of 13.1, which means we’re seeing it as it was just 330 million years after the Big Bang! The planetary…

BINOCULAR HIGHLIGHT Our targets this issue are the open clusters Messier 6 and Messier 7 in the tail region of the constellation Scorpius, the Scorpion. M6 is also called the Butterfly Cluster owing to its appearance, while M7 is known as Ptolemy’s Cluster after Claudius Ptolemy, who first recorded it around CE 130. To find the two objects, scan just north of the brightest star in the Scorpion’s tail — magnitude-1.6 Lambda (λ) Scorpii — or west from Gamma (γ) and Epsilon (ε) Sagittarii in the spout of the Sagittarius Teapot. I like to imagine the bright stars of the Teapot and the tail of Scorpius as hands supporting a cat’s cradle, with M7 firmly ensnared and M6 having made a narrow escape to the northwest. M7 is the bigger…

DUSTY CROWN The constellation Corona Australis (the ‘southern crown’) is located almost overhead on September evenings for those at mid-southern latitudes. Within it lies the binary star R Coronae Australis, which is accompanied by a blue reflection nebula called NGC 6729, seen above centre in this image. In roughly the same direction in the sky is a large, dark, dust cloud (centre). Also visible on the top-left outskirts of the nebulosity is a globular star cluster, NGC 6723. R CrA is thought to be only about 500 light-years distant, whereas the globular is more than 28,000 light-years away. Image courtesy Loke Kun Tan (StarryScapes.com).…

IMAGING IT SEEMS THAT EVERY FEW YEARS someone states, “We are in the golden age of astrophotography!” This is usually followed by a string of examples explaining why they believe it to be so. Here we are again at a crossroads, with astro-imaging gaining traction in popular culture beyond the amateur astronomy community. And much of this is driven by smartphones, microcomputers, CMOS detectors, and even gaming consoles. Deep sky astrophotography is again at the cusp of a revolution. We’re seeing things we never thought would be possible — mounts so accurate they don’t require guiding corrections during long exposures, cameras more sensitive than ever, and tiny computers that ride along with the telescope while orchestrating the tasks of a host of accessories. Astrophotography has an amazing journey ahead. Here’s…

When I publish a column about a particularly nifty telescope design, I’m often asked if the designer would consider making kits available for people who don’t have the shop capabilities to build one themselves. My usual response is “Alas, no,” but this time around I can anticipate those requests with a happy “Yes, indeed”. Robert isn’t selling kits, perse, so much as providing plans, building instructions, 3D-print files, and sources for the aluminium parts, lenses, mirrors, etc. Amateur telescope makers can 3D-print many of the parts for themselves or source them online, and a video series of assembly instructions will lead builders through the process of creating their own ‘Heart’ binoscope, in the videos, you’ll watch an 8-year-old child assemble one at a desk; I’m pretty sure you can do…

HOW TO SUBMIT YOUR IMAGES Images should be sent electronically and in high-resolution (up to 20MB per email) to contributions@skyandtelescope.com.au. Please provide full details for each image, eg. date and time taken; telescope and/or lens; mount; imaging equipment type and model; filter (if used); exposure or integration time; and any software processing employed. If your image is published in this Gallery, you’ll receive a 3-issue subscription or renewal to the magazine.…

24 to 28 OCTOBER 2022 The Tamworth Regional Astronomy Club Inc. offers you are a rare opportunity for an astronomy experience like no other. Visit observatories and be guided by experts as you link into the amazing world of citizen science in astronomy — comets, variable stars, hands-on astrophoto stacking and processing. Limited to 20 people. Register your interest early. 5 days in October 2022 $2,200 per person Register your interest: tamworthastronomy.com.au Contact: tracthestars@gmail.com 0427 668 802 0437 834 944…

Insight at Mars: Monster quake, powering down NASA’s Insight Mars lander witnessed the biggest quake yet in the nick of time — just before the craft began to run low on power. The record-breaker wasn’t strong by Earth standards, but it was the strongest quake recorded on another planet. The Seismic Experiment for Interior Structure aboard Insight noted the 5th-magnitude marsquake on May 4, 2022. Three days later, increasing dust in the air and on the solar panels caused the lander’s power levels to drop. The craft entered a pre-emptive safe mode on May 7 but was back to collecting seismic data as of press time. NASA has approved an extended mission through to December 2022, with most power being prioritised for the seismometer. To date, Insight has detected more…

WHEN These are standard times. Add 1 hour for daylight savings. 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 SW” is right-side up. About a third of the way from there to the map’s centre is Crux, the Southern Cross. Go out and look southwest about a…

The run of planetary oppositions continues in the latter half of 2022, with Jupiter and Neptune reaching this milestone in September and more to come in the following months. Mercury (mag. 0.5, dia. 8.4”, Sep. 5) begins September low in the western sky after sunset, with good viewing for the first half of the month. Then it will quickly slide toward the horizon as it heads for inferior conjunction (ie. between the Sun and the Earth) on September 23, after which it will reappear above the eastern horizon before sunrise. But don’t get your hopes up — the innermost world will remain within a few degrees of the horizon, making viewing quite difficult. Venus (-3.9, 9.9”, Sep. 15) is heading for superior conjunction (ie. on the other side of the…

ONE OF THE MOST FUNDAMENTAL principles of photography is that the more light you collect, the less image noise you’ll have. This is especially relevant when it comes to photographing the night sky, in which a good signal-to-noise ratio is vital for pleasing results. The bottom line is simple: More light (‘signal’) is good. You may think that boosting your camera’s ISO setting is an easy way improve the situation, but doing so only makes the image appear brighter and does nothing to increase the amount of recorded signal. This is not the solution you are looking for. Let there be light There are a number of ways to get more light to your camera’s sensor. The most obvious and intuitive approach is to increase the exposure length. You can…

Sequator Price: free https://sites.google.com/view/sequator What we like Freeware Automatic alignment and stacking Accepts RAW camera files What we don’t like Occasionally fails to align images accurately Auto brightness sometimes overly aggressive PHOTOGRAPHING THE STARRY SKY over a picturesque landscape can be challenging. The best results tend to come from photographers using the latest digital cameras and fast lenses. In addition, exposures lasting more than 10 seconds or so also require the camera to be mounted on a star tracker in order to record stars as pinpoints of light rather than elongated streaks. That’s a significant piece of extra equipment if you’re travelling to a scenic vista to capture the star-filled sky. But what if the only gear needed to take deep nightscapes were your camera, lens and tripod? And what…