Indholdsfortegnelse for August 2023 i BBC Sky at Night

The latest astronomy and space news, written by Ezzy Pearson BULLETIN The Hubble Space Telescope has been fighting an increasingly difficult battle in recent years against satellites leaving bright trails across its images, but a new piece of software could provide a valuable weapon in efforts to remove them. When Hubble launched in 1990, there were only around 470 satellites in orbit. Today there are close to 8,000 and the number is rising fast. As the telescope sits in low-Earth orbit, many of these satellites pass above it, crossing its field of view and leaving bright streaks across its images. In 2022, around 10 per cent of Hubble images were affected by such interlopers. Fortunately, the problem only affects a small part of each image’s field. “The average width I…

Astronomers have witnessed galaxies clearing the early Universe’s obscuring fog of opaque gas for the first time, thanks to the James Webb Space Telescope. A few hundred million years after the Big Bang, space was filled with cool gas that absorbed most of the light travelling through the cosmos. There then followed what is called the Era or Epoch of Reionisation, where starlight from the first galaxies heated the gas, turning the Universe transparent by the time it had reached an age of one billion years old. To see this in action, researchers examined bright quasars from this era, the light of which shines through the honeycomb of opaque gas and clear bubbles, illuminating transparent regions two million lightyears in radius. “We expected to identify a few dozen galaxies that…

It may often seem that amateur astronomy is dominated by large telescopes, expensive imaging kit and smartphone apps, but in fact there is still one branch of amateur astronomy that requires practically nothing at all: meteor observing. Although there can be sporadic meteors all year round, we usually observe them when wellestablished showers are underway. And perhaps the best-known annual meteor shower of them all, the Perseids, takes place this month. With the Moon only a slender waning crescent and very little moonlight to drown meteors out, the prospects for this year’s shower are looking good. The Perseid meteor shower gets its name from its radiant (the point in the sky where the meteors appear to come from) being in the constellation of Perseus. In much the same way, the…

Eclipses are one of nature’s most mesmerising spectacles. Eclipse-chasers are often willing to fly half-way around the world to remote, hard-toreach locations just for the chance to see the phenomenon. The coming months, however, mark a unique opportunity as not just one but two eclipses are set to cross one another over North America. On 14 October 2023, a ‘ring of fire’ annular eclipse will pass across 10 countries, with a long section of the path running straight through the USA. But this will just be a warm-up to the second event 177 days later on 8 April 2024, when a total solar eclipse will pass across the USA, Mexico and Canada, with an estimated 32 million people living inside the path of totality. There’s even a region in Texas…

1. M11, the Wild Duck Cluster 10 × 50 Our tour of the southern portion of the Milky Way begins with one of the densest open clusters, M11, the Wild Duck Cluster. You’ll find it 2° southeast of mag. +4.2 Beta (β) Scuti, spanning about 0.25° of sky. In 10×50 binoculars, the cluster appears as a bright, slightly wedge-shaped glow. Were it not so rich, you may have had trouble identifying it against the Scutum Star Cloud, the densest part of the Milky Way. □ SEEN IT 2. M26 15 × 70 If you put mag. +3.8 Alpha (α) Scuti at the northwest of your field of view, open cluster M26, also known as NGC 6694, will be southeast of centre. Although it is only mag. +8.0, M26 is easy…

Every amateur astronomer starts off loving the Moon. They eagerly set up their telescopes in their garden, squint into the eyepiece and check what they can see against charts in books or magazines, looking for the ‘celebrity’ lunar features they’ve heard and read so much about. They whisper in the darkness as they make one discovery after another. “Ah… so that’s Copernicus!” “That must be Tycho!” “Wow, they must be the Apennine Mountains.” “Is that… yes, I think it is… the Sea of Tranquility!” But after a while, the love affair between many new amateur astronomers and the Moon cools. They’ve seen all the ‘good stuff’ – the major craters, the most obvious mountain ranges, the ripples on the floors of the seas, and so on – and the Moon…

Predicting the solar cycle is important not just to solar scientists hoping to learn more about our star, but is a practical concern for almost everyone on Earth. Modern society is increasingly reliant on satellites to help us communicate, navigate and monitor our planet. When the Sun is highly active, it releases high-energy particles that can knock out electrical systems on satellites. Solar storms can even cause the atmosphere of our planet to expand. When this occurred in February 2022, just after a batch of SpaceX’s Starlink satellites had been deployed into low orbit, the extra drag meant they were unable to reach their intended altitude and dozens crashed back to Earth. Though our planet’s magnetic field shields us from the worst of space weather, it can cause problems on…

The night sky can be breathtaking, especially when it contains bright views of the Milky Way from a darksky location. But what’s the best way to capture the entire stretch of the night sky? There are several methods, but as ever compromises have to be made. A camera with an interchangeable lens system such as a DSLR or mirrorless camera gives you the best of all worlds, allowing you to go wide-angle or mid-angle. A wide-angle lens has a focal length of 17mm or less, a mid-angle is 18-40mm. Anything over this is getting in too close to the subject to be considered all-encompassing. If you choose a mid-angle focal length, you’ll be able to cover a decent portion of the Milky Way, but you’ll need to consider mosaicking shots…

VITAL STATS • Price £3,989 • Optics Air-spaced apo quadruplet (two ED lenses) • Aperture 130mm • Focal length 1,000mm, f/7.7 • Focuser CNC-machined, dual-speed rack and pinion • Extras Tube rings, dovetail bar, finder-scope bracket, carry case, 2-inch eyepiece adaptor, camera adaptors • Weight 10.2kg; 12.5kg with supplied case & accessories • Supplier First Light Optics • Email questions@firstlightoptics.com • www.firstlightoptics.com Following in the footsteps of Askar's successful 107PHQ flatfield apo, we take a look at its bigger brother, the 130PHQ. Arriving in a single, very large box, the first thing we noticed about Askar's largerstaperture refractor was the weight, so we were glad we didn't have to carry it too far! Opening the box revealed a substantial and extremely robust carry case, with the telescope held very securely…

1 Vixen widefield 2.1×42H binoculars Price £329 • Supplier Telescope House www.telescopehouse.com These 2.1× magnification binoculars enhance your night-sky observing while maintaining a wide field of view, granting an impressive view of stars in the Milky Way and the constellations. 2 Kendrick transparent Bahtinov masks Price from £35 • Supplier The Widescreen Centre www.widescreen-centre.co.uk Focus your astrophotography setup even faster with a transparent mask that produces much larger diffraction spikes than its opaque counterparts. Sizes range from 50mm to 14 inches to ensure a snug fit. 3 Dual-Palm rechargeable hand warmers Price £34.99 • Supplier Ellis Brigham www.ellis-brigham.com Warm your fingers throughout the night with this pair of rechargeable hand warmers. You can either use them separately or magnetically click them together to create a single heat source. Each warmer…

AUGUST HIGHLIGHTS Interview: Making spaceflight global Mishaal Ashemimry from the Saudi Space Commission on growing the space industry across the globe. The Sky at Night - The UK Space Race Watch this episode of The Sky at Night, in which Maggie and Chris learn about the UK firms launching into space. Download a meteor observing form Use this to record your observations of meteor showers. See page 28 for a complete guide to this month’s Perseids. The Virtual Planetarium…

Could Betelgeuse go supernova within the next few decades? Two papers are arguing whether that might be the case. Betelgeuse, a red supergiant 500–600 lightyears from Earth will one day go supernova, but exactly when that might be is a subject of much debate. One study led by Hideyuki Saio from Tohoku University in Japan simulated the star’s vibrations, leading them to believe the star could be in the final stages of its life, where it is burning carbon in its core. This stage will only last around 1,000 years and once the fuel is exhausted, the star would go supernova within a decade. However, another group led by László Molnár from Konkoly Observatory in Hungary has since replied with their own measurements of Betelgeuse’s vibrations that suggest the star…

A solar flare strong enough to knock out shortwave radio communications over North America for 45 minutes struck Earth on 20 June. The flare was one of an increasing number of X-class flares – the strongest type of solar flare – seen erupting in recent months, as the Sun enters the most active portion of its 11-year solar cycle. Shortwave radio communications, such as those used by aviators and international radio broadcasts, bounce signals off the upper level of Earth’s atmosphere, called the ionosphere. However, the electromagnetic radiation released when a large solar flare erupts can ionise this atmospheric layer, stopping the signals from bouncing properly. The flare was accompanied by a coronal mass ejection (CME) travelling at 3.5 million km/h, though this predominantly missed Earth. Had it hit, such…

Everything we know about life – what it is, what it looks like and how it works – has come from studying life on our planet. This creates a problem for those of us who look for signals from extraterrestrials. How can we plan to communicate with an extraterrestrial intelligence, when we’ve not even found evidence for the existence of any form of alien life at all? You might think that alien life will be very different from life on Earth – very alien. But that may be a little pessimistic. While it’s good to be cautious and to remember that our experiences on Earth may not prepare us fully for all the weird and wonderful possibilities that exist across the Galaxy, it’s also true that not everything is possible.…

Meteor observing doesn’t require any specialist equipment, but there are a few things that will make your session far more comfortable. You can of course watch the shower in an ordinary chair, but a reclining outdoor chair or a sun lounger is very helpful. You’re going to be looking up at the sky for long periods, particularly later in the night when Perseus is high in the sky, and a reclining chair will prevent neck strains. You will also need a clipboard and a copy of the BAA meteor reporting form (see overleaf). Other useful items include a red torch and some pencils or pens. Don’t forget to bring warm clothing or a blanket. It can get a bit chilly and damp in the early hours. A hot drink, some…

There are several types of cameras you can use for astrophotography, such as DSLRs, smartphones, modified webcams and dedicated CMOS planetary cameras – all of which I’ll come to in a moment – but they all follow the same basic principle of recording a video of the planet, thereby capturing thousands of images in quick succession. The weakest link in any optical setup is Earth’s atmosphere and an effect known as seeing, which causes light travelling through it to shimmer. We can’t predict moments of low shimmer, but videoing means we can be sure to catch them and then only use the best frames from a video during the processing stage. Before you begin photographing the planets, it’s important to make sure your optical setup is as sharp as it…

The Moon’s elliptical orbit means sometimes it blocks all but the outer edge of the Sun, leaving an annulus (ring) of light: an annular solar eclipse. You’ll need suitable solar filters to view it, but it’s a sight well worth making the journey to behold. During October’s eclipse, the Moon will cover almost 91 per cent of the Sun for up to 5 minutes and 17 seconds. The path of annularity, where you’ll see the ‘ring of fire’, will touch land in Oregon at 09:13 PDT (16:13 UT) moving southwest until it leaves Texas at 12:03 CDT (17:03 UT), before passing over Mexico, Belize, Guatemala, Honduras, Nicaragua, Costa Rica, Panama, Colombia and Brazil, where it will finally end at 16:48 BRT (19:48 UT). The path of annularity will be up…

PICK OF THE MONTH Saturn Best time to see: 27 August, from 01:18 BST (00:18 UT) Altitude: 25° Location: Aquarius Direction: South Features: Subtle banded atmosphere, rings, moons Recommended equipment: 75mm or larger Saturn reaches opposition on 27 August and this month the view is excellent. On 1 August, it reaches its highest position under relatively dark skies, a situation that only improves throughout the month. At its highest, it appears 25° up as seen from the centre of the UK. Although still rather low, this is a big improvement over recent years and under good seeing should allow decent views of the planet and its rings. At opposition, Saturn will shine at magnitude +0.3. A few days before opposition, the planet’s distinctive rings should appear to exhibit a subtle…

Comet C/2020 V2 ZTF is a small telescope target, heading south all month. It stays more or less the same brightness throughout August, starting the month at mag. +9.8 and ending it at mag. +9.7. It’s an early morning object, starting its monthly track just east of the ‘head’ of Cetus the Whale, a pattern of stars conveniently located south of bright Jupiter. Look for it 2.3° to the east-northeast of Menkar (Alpha (α) Ceti) on the morning of 1 August. Its path then takes it south, arcing subtly west. The Moon interferes with the view early in August, passing north of the comet at its last quarter phase, on the morning of 8 August. This isn’t too much of a problem though, because the lost viewing time at the…

Venus reaches inferior conjunction on 13 August (see page 47), when at 12:15 BST (11:15 UT) it will pass 7.7° from the centre of the Sun. With care you can make a record of this, which is this month’s challenge. First and foremost, pointing a telescope close to the Sun is dangerous and extreme care needs to be exercised. If you’re not sure what you’re doing, we strongly recommend that you don’t attempt this challenge. The safest setup to use would be a small to mid-sized refractor along with a high-frame-rate camera fitted with a red or infrared pass filter. Don’t attempt to see this visually. Any finderscopes will also need to be capped or removed. You’ll need a full-aperture white-light solar filter and for the purposes of this challenge…

Things have been hotting up on the Sun over the last few years. In December 2019, its surface was a very quiet place, a time known as the solar minimum. In the years since, it has been gradually waking up, with sunspots and flares being sighted across its surface. This activity is expected to reach its peak in the coming year or so, after which it will fall back into slumber once more, heading towards a new minimum. This pattern of rising and falling activity is known as the solar cycle. “The solar cycle is driven by the magnetic field of the Sun,” says Stephanie Yardley, a solar scientist from the University of Reading. “Approximately every 11 years the Sun’s polar magnetic field reverses polarity – it swaps direction.” This…

The climate on Earth is just right to support a rich diversity of life on land and in the oceans. The abundance of water, the warmth and energy from the Sun, and interactions within Earth’s atmosphere create weather systems, while the motion of Earth gives rise to seasons. We do, however, experience extremes. Death Valley in Arizona holds the record for the highest air temperature recorded, in 1913 – a blistering 56.7°C (134.1°F) – and in 1983, the air temperature in Vostok, Antarctica, dropped to –89.2°C (–128.6°F). But if you think that’s extraordinary, it’s nothing compared to the rest of the Solar System! Mercury Mercury is the smallest planet in the Solar System and the closest to the Sun. It spins almost upright on its axis and doesn’t have any…

The best way to produce your own full-colour image of Saturn is to first capture a correctly focused and exposed video of the planet, a minute or so long, using an astronomical digital camera at the focus of your driven telescope. Here I’ll explain how you then process this video to create a single final image of the planet; I’ll assume you are using a colour digital video camera as this is the easiest way for you to produce a full-colour image. At the processing stage, you use special software to break your video down into separate frames, rate each frame for quality, then align the best ones so that they all lie exactly on top of one another. This results in a single-frame stack. This stack is effectively a…

CURIOSITY ROVER, 13 JUNE 2023 This picture of the Marker Band Valley on Mars was created by combining two panoramic shots of the region – one taken in the morning and one in the evening – and then adding colour. Each panorama was in turn constructed from five individual images taken by Curiosity’s black and white navigation cameras. It’s likely that this winding area is the site of an ancient lake, unexpectedly discovered by the rover. Visible in the picture are the hills Bolivar and Deepdale, which Curiosity recently drove between, along with several other small hills, all of which lie within Gale Crater. The crater’s rim can be seen 40km away, while the peak of an 87km-distant mountain is just visible beyond. Also visible are Curiosity’s tracks, along with…

BULLETIN Of the 5,000 planets beyond our Solar System discovered so far, around half were found by NASA’s Kepler Space Telescope. Now astronomers believe they have identified the last three planets the telescope ever uncovered. Kepler launched in 2009, spending four years monitoring 150,000 stars, looking for the dip in brightness caused by a planet passing in front. In May 2013, however, the second of the spacecraft’s four reaction wheels – which helped keep it steady – failed. The Kepler team eventually found another way to stabilise the craft and conducted the K2 observing campaign which ran until the telescope used up its fuel, officially retiring on 30 October 2018. Kepler’s last observation run was able to get one week of high-quality observations of 33,000 stars, followed by 10 days…

Our experts examine the hottest new research CUTTING EDGE There are plans for a lot of crewed missions to the Moon in the coming years. Artemis, led by NASA but with involvement of ESA, JAXA and the Canadian Space Agency as well as commercial spaceflight partners, aims to return the first humans to the Moon since the Apollo programme. If all goes well, this will be followed by the establishment of permanent human settlements on the lunar surface. All of this would involve landing not just the crews themselves, but all the habitats and infrastructure needed to support them on the surface, and so requiring a lot more – and crucially, much heavier – landers than used by Apollo. One important consideration for such massive landers, say Philip Metzger at…

From the James Webb Space Telescope’s amazing Pillars of Creation photo to the Event Horizon’s image of a black hole, we’ve captured many dramatic and colourful representations of space in a visual sense. We’ve also captured sounds from space, whether that’s the eerie electron ‘whistler waves’ produced by Earth’s Van Allen belts or a meteor’s sonic boom as it streaks across the night sky. But what about the smell of space? In fact, space carries a whole array of odours and to experience some of them we need not travel very far. One such on-your-doorstep occurrence came courtesy of the Winchcombe meteorite. Zipping over the UK on the last day of February 2021, it was widely witnessed, captured by everything from doorbell cameras to vehicle dashcams. After its impact in…

Estimating meteor magnitudes seems straightforward on paper – just compare the meteor to a star of similar brightness – yet in practice it can be a little more challenging. Meteors rarely hang around for long, so it will often be the memory of the sighting you are comparing! Comparing meteors you observe to the stars in this table will give you their approximate magnitude; you only need to estimate to the nearest whole magnitude. Generally, the brighter the meteor, the larger the debris that is colliding with Earth’s atmosphere. If you observe a brilliant fireball as bright as Jupiter, record its magnitude as –2. If a faint meteor about as bright as Polaris (the Pole Star) is seen, record its magnitude as +2, and so on. Remember, the fainter an…

It’s possible to take planetary photographs with a DSLR or even a smartphone, with the help of adaptors. DSLR adaptors fit directly into your telescope’s eyepiece holder, while smartphones will also require an eyepiece as they hold your phone’s camera over it, allowing you to capture a view similar to what you’d see with your eyes. Be sure to align the smartphone holder precisely or the brightness of the image will fall off catastrophically. The camera needs to be centred over and laid flat against the eyepiece so that the edges of your view through the eyepiece appear sharp. These kinds of images are great if you’re just looking for a quick snap to remember the night or want to test the waters of planetary photography, but they’ll be of…

The southern end of Aquila the Eagle, as it approaches Scutum the Shield, is marked by a small curve of stars starting with mag. +3.4 Althalimain (Lambda (λ) Aquilae), then mag. +4.0 12 Aquilae and finally mag. +4.8 Eta (η) Scuti. Althalimain (or Al Thalimain) is derived from the Arabic ‘the two ostriches’. If you’re wondering where the other ostrich is, 8.4° to the northwest is mag. +4.3 Iota (ι) Aquilae which is also named Althalimain. Strictly speaking, as Lambda leads Iota across the sky, Lambda Aquilae should be known as Althalimain Prior. Lambda has a spectral type B9 Vn. ‘B9’ means it’s a hot star of around 11,800 Kelvin which appears blue-white. ‘V’ means it’s a main sequence dwarf and ‘n’ indicates that its spectrum shows broad absorption lines…

For those that don’t have specialist solar telescopes or Sun-monitoring satellites, the most obvious way to see the swell of the solar cycle is via the aurorae. The Northern and Southern Lights are caused by solar wind particles getting trapped in our planet’s magnetic field. Earth’s field lines guide the particles down, forming a ring around either pole, known as the auroral oval, until they strike particles in our atmosphere, causing them to emit light photons, which we see as the aurorae. Though they can occur at any time, the Northern Lights are best viewed between September and March, but good displays can happen in the months in between too. When solar maximum arrives (possibly as early as late 2023), your chances of a spectacular display will vastly improve as…

PHOTO OF THE MONTH M27, the Dumbbell Nebula Patrick Cosgrove, Honeoye Falls, New York, USA, 2–4 August 2021 Patrick says: “M27 was a childhood favourite. I wanted to see what detail I could capture of the outer gas shell, so I photographed this in narrowband in 2021. I was amazed at how different the individual Ha, OIII and SII images were from one another! More recently, I went back and enhanced the detail in the outer shell, which provides a very different view of M27.” Equipment: ZWO ASI2600MM Pro camera, Astro-Physics 130mm f/8.35 StarFire EDT refractor, iOptron CEM60 mount Exposure: 39× 300’ Ha, 28× 300’ OIII, 46× 300’ SII Software: PixInsight, Photoshop Patrick’s top tips: “Anyone interested in deep-sky imaging should consider starting with a shorter-focal-length scope and a one-shot…

VITAL STATS • Price £2,298 (mount), £275 (iOptron CF tripod) • Mount type Strain wave, equatorial/ altaz • Load capacity 13.5kg (18kg with optional counterweight) • Slew speed 9 speeds, up to 8° per second • Power 12v DC 5A • Autoguider port ST4 • Handset Go2Nova 8409 with inbuilt Wi-Fi • Protocols ASCOM, INDI, iOptron Commander • Weight 3.6kg • Supplier Altair Astro • Email info@altairastro.com • www.altairastro.com Astronomy mounts with harmonic drives have special gear systems rather than the usual worm gears and have become a bit of a trend recently, being smaller and lighter for their weight-carrying capacity. iOptron has now introduced a new one, the HAE29 with iPolar, which uses strain wave gears in its right ascension and declination axes, and has both equatorial and altazimuth…

Can you tell us a bit about our planetary neighbour Saturn? Saturn is a ‘gas giant planet’ nearly 10 times wider than Earth and made mostly of hydrogen. It has a ring system and rotates fast; a day on Saturn is just 10 and a half hours. It’s a very interesting world because of its rings, which have become a symbol of the Solar System – when you look at illustrations that symbolise science at a Science Festival, you’ll almost always see images of Saturn. What are Saturn’s rings made of? They’re made of ice that is nearly completely composed of water, with a little bit of dust that has been picked up over aeons. The ice is made of fragments, from dust-sized particles all the way up to bus-sized…