Indholdsfortegnelse for April 2024 i BBC Sky at Night

The latest astronomy and space news, written by Ezzy Pearson BULLETIN A galaxy that shouldn't exist is challenging astronomers’ understanding of how these enormous stellar structures grow in the early Universe. Despite its relative youth, recent observations of galaxy JWST 7329 have shown it has far more stars than it should have had time to grow. It was first spotted in 2010 in an infrared sky survey and immediately struck astronomers as being something special. Ground-based follow-up observations proved inadequate, however, and astronomers had to wait until the James Webb Space Telescope (JWST) came online to take a spectrum of it. The galaxy is so far away that we are seeing it as it was 11.5 billion years ago, just two billion years after the Big Bang. Even at this…

After almost 1,000 Martian days and 72 flights, NASA's Ingenuity helicopter has officially reached the end of its mission. Ingenuity's final expedition on 18 January was meant to be a short flight to re-establish its position after a previous emergency landing. However, it rose just one metre before communications failed. Ground control then discovered the rotor blades were damaged, permanently grounding the craft. Ingenuity travelled to Mars with the Perseverance rover and first flew on 19 April 2021. The craft was designed for just five flights, to test the feasibility of using rotocraft in the thin Martian atmosphere. These were so successful that the mission was extended for another three years, during which time it survived dust storms and the Martian winter. “History's first Mars helicopter will leave behind an…

Our experts examine the hottest new research CUTTING EDGE Planetary scientists get particularly excited about finding caves on Mars. Such subterranean structures offer very promising locations for establishing human habitats – their rock ceilings would provide protection from dust storms and micrometeoroid impacts, as well as shielding from cosmic radiation. They also represent enticing targets for searching for signs of simple martian life, as caves on Earth often sustain abundant microbial growth. Lava tubes are one promising source of Martian caves. These tubes form when a stream of volcanic lava develops a hardened crust on top, but continues to flow within, then empties to leave behind a hollow tunnel beneath the surface. On Earth, they range from just a few metres long to the enormous 65km-long Kazumura Cave in Hawaii,…

PICK OF THE MONTH Best time to see: 1 April, from 19:20 UT Altitude: 23° Location: Aries Direction: West Features: Complex markings, Galilean moons Recommended equipment: 100mm scope or larger None of the planets are particularly well-placed this month, all lying very close to the Sun. Those that do re-emerge into the dawn twilight do so at a low altitude. Jupiter and Uranus remain in the evening sky, but not for much longer. Jupiter is best seen at the start of April, when it appears above the western horizon as the sky darkens after sunset. It's losing altitude now, a little over 20° up when it starts to become visible after sunset at the start of April. By the end of the month you'll be hard-pressed to find it at…

Comet 12P/Pons–Brooks is currently in the evening sky. Its brightness is expected to increase slightly throughout April, but the rapid expansion of evening twilight means your best chance of spotting it will be at the start of the month. As its name suggests, it was the 12th comet to have the periodic nature of its orbit calculated. Its orbital period is 71 years. Its next perihelion occurs this month on 21 April, making 2024 a particularly good year to try to find it. 12P/Pons–Brooks's orbit is highly inclined at 74.2°. At aphelion, it moves to a position 33.6 AU from the Sun, which is just further out than the orbit of Neptune. At perihelion, it moves to a position slightly further out than the orbit of Venus, at 0.8 AU.…

It's impossible to sugar-coat the fact that the main planets are poorly positioned at present, a situation that will persist until the start of the second half of 2024. However, it's still possible to get your planetary fix by hunting down the conjunctions on view this month (see page 47 for the full details). Looking at how these are located against mostly bright skies, you might be forgiven for thinking it's a bit of a lost cause, but a bit of effort and luck with the weather can reap rewards. There are tricks that can help you succeed. One is to use a planetarium app to determine exactly where a conjunction will be relative to your horizon. Try to find it at the last minute and the lack of sky…

Comet observers are all hoping for big things from comet C/2023 A3 (Tsuchinshan–ATLAS) this autumn. When it was discovered, it was hailed as a potential ‘comet of the century’ and calculations suggested it might become as bright as mag. -4! It's now thought that at best A3 will reach mag. +0.4, a lot fainter but still much brighter than the last really bright comet, C/2020 F3 (NEOWISE), which delighted sky-watchers in summer 2020. At the moment, A3 is a 13th-magnitude speck in Libra, visible only through large telescopes and on long-exposure images. By the end of September, it will be a morning object, perhaps shining as brightly as mag. +0.6, but rising just before the Sun. Our best views of A3 will come when it moves up into the evening sky…

Age: 4.46 billion years Although Earth formed at the same time as the other Solar System planets, it wasn't initially accompanied by a moon. Instead, the Moon is thought to have been created later, in the aftermath of a collision between young Earth and another infant planet the size of Mars, called Theia. The impact created a plume of debris that eventually coalesced to form the Moon. To discover when this happened, geologists need Moon rocks, which we luckily have in abundance thanks to the Apollo missions. These were taken from a variety of locations across the lunar surface and so give a variety of different ages. For many years, the oldest rock was thought to come from samples collected by the Apollo 14 mission. However, to commemorate the 50th…

Step 1 With the camera body suitably supported, unbolt the cover from the desiccant port on top of the camera using an Allen key or screwdriver as appropriate for your camera. Carefully remove the cover and place it on a clean, dry surface for safe storage. Step 2 Remove the micro-sieve plug and carefully detach its ‘O’ ring, as under no circumstances should the ‘O’ ring go in the oven. Cover the camera's exposed port with a clean lens cloth. With a clean, dry cloth, remove any contamination from the surface of the plug. Step 3 Preheat the oven, then place the plug on a clean baking tray and put it on a high shelf. Bake for the time and at the temperature recommended by the manufacturer (260°C for four…

Lunar occultations of the planets are rare and exciting events to photograph. Their relatively quick progression presents astrophotographers with unique challenges beyond typical lunar and planetary imaging. In 2023 my photograph ‘Mars-set’ was chosen as the overall winner of the ‘Our Moon’ category of the Astronomy Photographer of the Year competition. Here I'm going to walk through the basic steps of recording and processing a lunar occultation of a planet – Mars, in this specific case In a nutshell, you'll need to record a raw video of the occultation and stack a small snippet of 100–200 frames. Carefully sharpen the stack with wavelets, apply denoise and colour balance it. If maximum detail on the planet is desired, we can use another stack of frames of the planet captured before or…

VITAL STATS • Price £499 • Sensor IMX585 STARVIS 2 BSI • Resolution 8.3MP, 3,840 x 2,160 pixels • Exposure range 0.1ms–1,000 seconds • Frame rate Full resolution 47fps at 8 bit, 23.4fps at 12 bit • Connectivity USB 3.0, USB 2.0 compatible, ST4 • Size 80mm x 65mm • Weight 295g • Extras USB cable, ST4 guide cable, 2-inch OD nosepiece, CS-mount insert, dust cap, software • Supplier Altair Astro • Email info@altairastro.com • www.altairastro.com When you look at Altair Astro's impressive range of astronomy cameras, it might not be immediately obvious where the Hypercam 585C fits in, given that there's a divide between cameras for deep-sky images and smaller variants suited to Solar System and auto-guiding applications. In fact, the 585C sits neatly in the middle of both…

This spring, comet C/2021 S3 PanSTARRS has been passing by Earth, and now space scientists need your images of it. “We need lots of timed photos of the comet to build up a picture of its journey through our Solar System,” says Sarah Watson, a PhD researcher from the University of Reading who is leading the project. Watson's team will use the images to study the behaviour of the comet's tail throughout its journey. The tail is created by the Sun's heat melting the ice that the comet is made of, which is then swept away from the Sun by the solar wind. As such, comet tails act as cosmic windsocks, showing the direction and strength of the solar wind in the region around the comet. “This is a fantastic…

BULLETIN In the first US venture to the lunar surface since the Apollo 17 landing in 1972, the Odysseus lunar lander touched down on the Moon at 23:23 UTC on 22 February. The lander appears to have tipped over during the landing, but is operating well regardless. Odysseus was built and is operated by US private spaceflight company Intuitive Machines as part of the IM-1 lunar mission, making this the first-ever soft landing on the Moon by a private spacecraft. The mission launched from the Kennedy Space Center at 06:05 UTC on 15 February, on board a SpaceX Falcon 9 rocket, with a target landing site of crater Malapert A, located around 300km from the lunar south pole. Unfortunately, the landing was far from straightforward. Problems with the primary navigation…

The black hole at the centre of our Milky Way, Sagittarius A* (Sgr A*) is spinning so fast that it's pulling spacetime around it into the shape of a rugby ball, a new study has found. Black holes are governed by two fundamental properties: mass and spin. Using radio and X-ray observations of the region around Sgr A*, astronomers have found that the black hole appears to be spinning at 60 per cent the maximum possible value. The rapid spin pulls on the surrounding spacetime, meaning it would resemble a rugby ball viewed from the side. If there is gas surrounding a black hole, a rapid spin can fire this material out in a powerful jet. The lack of gas surrounding Sgr A* means that it is currently quiet, though…

CAUTION Never observe or image the Sun with the naked eye or any unfiltered optical instrument Photographing a total eclipse of the Sun is exciting. To make the most of it, though, requires some pre-planning. In this article, we'll suggest ways to make it as enjoyable and stress-free as possible. If you've never photographed a total solar eclipse before, trying to catch everything that happens may be overambitious. Instead, only tackle what you're comfortable with and do plenty of rehearsals, as then you'll be able to fully enjoy the day First, let's think about kit. Many different imaging devices can record an eclipse, but the demands of travelling to a specific location typically mean that self-contained units such as DSLRs are popular. Plenty of charged batteries and SD memory cards…

1 Monday The first half of April provides good, Moon-free opportunities to attempt this month's Deep-Sky Tour on page 56. This month we're looking at objects close to the border of Boötes and Coma Berenices. 2 Tuesday Possibly naked-eye comet 12P/Pons– Brooks will be visible in the evening twilight this month. The best time to spot it will be at the start of April. Turn to page 53 for more details. 4 Thursday The galaxyheavy region of sky known as the Realm of Galaxies is well placed in moonless skies currently. Multitudes of galactic smudges can be found in the region within and north of the Bowl of Virgo asterism. 6 Saturday A 9%-lit waning crescent Moon is near Mars and Saturn as they rise above the eastsoutheastern horizon in the dawn twilight. 7 Sunday The 1%-lit…

Megrez (Delta (δ) Ursae Majoris) is one of the easiest stars in the night sky to locate. It's the one that joins the handle of the Plough asterism to its blade. For those who don't know what an old-fashioned plough looks like, the pattern is also known as the Saucepan, Megrez joining the handle to the pan. Even if you forget its position, it's easy to identify as it's the faintest of the seven Saucepan stars, shining at mag. +3.3. In the bigger picture, Megrez also marks the point where the Great Bear's tail joins its body. This is emphasised by Megrez's Arabic translation: the base [of the bear's tail]. Normally in this section we discuss stars that make our Sun look rather puny, but not so Megrez. It's only…

Compared to the history of the cosmos, the span of humanity's existence has been little more than the tick of a clock. And yet that hasn't stopped astronomers from looking up at the stars and trying to fathom how long they have shone in the skies above us. Measuring the age of something that was around millions, if not billions, of years before our earliest ancestors walked the Earth is far from straightforward, however. Here, we take a look at how astronomers have managed to measure the age of the cosmos, from our own planet, to our neighbouring stars, and even the Universe itself.…

Age: 13.8 billion years The Universe began with the Big Bang, sending all the matter and energy of the Universe rushing outwards. It's been expanding ever since. If we could measure how fast this expansion is happening, in theory it should be possible to backtrack and work out how old the Universe is. Cosmologists think they know the rules of how this rate of expansion has changed over time, but to use these to work out the Universe's age, they need the rate of expansion in today's Universe, called the Hubble constant. Unfortunately, the exact value of the Hubble constant is one of the biggest controversies in cosmology today. The issue is there are two methods of measuring the expansion and they don't quite agree. The first is the ‘late…

Take the perfect astrophoto with our step-by-step guide ASTROPHOTOGRAPHY CAPTURE CAUTION Never observe or image the Sun with the naked eye or any unfiltered optical instrument As you'll see elsewhere this issue, there's a total solar eclipse visible across North America this month. The USA's second in five years will mean they are ready to max out on this one. And why not? A total eclipse of the Sun is an amazing, spectacular event. In the UK, we're too far away from totality to be able to see anything close to a total, but if you live in the western part of the country, you do stand a chance of seeing a partial solar eclipse at sunse As this event will be a partial solar eclipse with plenty of the…

FREE BONUS CONTENT Find our extended Gallery at www.skyatnightmagazine.com/ bonus-content The Heart Nebula Graham Prescott, St Albans, Hertfordshire, December 2023–January 2024 Graham says: “I wanted to capture the entire nebula, but it was much larger than my field of view. I've never tried a mosaic before, but thought I'd give it a go, though stormy weather meant it took two months to complete. Stitching the processed stacks to ensure consistency was challenging, as was getting the colour balance, but the end result was beyond what I thought possible with my current setup.” Equipment: ZWO ASI294MC camera, Sky-Watcher Explorer 150P-DS reflector, Sky-Watcher EQ5 Pro mount Exposure: 11h of 60” subs x 4 panels Software: DeepSkyStacker, Siril, StarNet++, Image Composite Editor, GIMP Graham's top tips: “Start with a robust, basic setup and…

How are you using exoplanet atmospheres to look for life? Life impacts our atmosphere on Earth. The amount of oxygen in our atmosphere is in a disequilibrium state; there's something constantly replenishing it in our atmosphere – and that's life. If all life on Earth was to suddenly disappear, the oxygen in our atmosphere would disappear. The idea is that if we can see the same signature of disequilibrium elsewhere, that starts to become a signature that maybe life is causing that. What molecules are you looking for? There are four main molecules that we focus on when talking about Earth-like life: oxygen, water, carbon dioxide and methane. There are other less abundant things out there that might signal life as well, molecules that can only be made by life.…

EYE ON THE SKY HUBBLE SPACE TELESCOPE, 26 JANUARY 2024 The two blue beauties seen in this picture are NGC 5410 and UGC 8932, a pair of interacting galaxies that can be found some 180 million lightyears from Earth in the constellation of Canes Venatici. NGC 5410, the larger of the two, is a barred spiral galaxy that was first observed by William Herschel in 1787. It measures 80,000 lightyears across and, like its smaller companion, has a distinctly blue colour. That's because both galaxies are rich in young, hot stars. Blue stars are hotter than red stars such as our own Sun, and because they emit more energy, tend to be shorter-lived. The unusual shape of UGC 8932 is believed to be due to the gravitational pull of its…

A hugely bright object known as a quasar has now been confirmed as not just the brightest known example of its kind, but also the most luminous object ever observed. A quasar forms when the accretion disc of gas and dust around a supermassive black hole at the heart of a galaxy becomes so hot it begins to glow brightly. To us here on Earth, the result closely resembles a star. This particular quasar, J0529-4351, was actually spotted in images as far back as 1980, but it was misidentified for decades. It was only when astronomers re-examined it with observatories such as the Very Large Telescope that they realised how luminous it truly was. The record-breaking galaxy weighs in at 17 billion solar masses. It devours a Sun's worth of…

A stunning batch of images featuring 19 spiral galaxies, taken by the James Webb Space Telescope (JWST), has just been released to the public. The images are at unprecedentedly high resolution, allowing astronomers to investigate how the small-scale structure of galaxies influences their large-scale development. The blue regions show the location of millions of sparkling stars, while the red regions show warmly glowing gas. They were processed as part of the Physics at High Angular Resolution in Nearby Galaxies (PHANGS) programme, which uses the world's best observatories to image nearby galaxies across a range of wavelengths. “This programme has a huge volume of data, and JWST is an extremely complex observatory,” says Thomas Williams from the University of Oxford and part of the PHANGS team. “It means we may be…

Back in June 2021, our space equipment company Oxford Space Systems was honoured to feature in the ‘Space Boom Britain’ episode of The Sky at Night and then in BBC Sky at Night Magazine. We had a tremendous reaction from viewers and readers who were fascinated to learn about our business of designing and manufacturing deployable antennas for space. These can fit into as small a space as a 10cm cube for launch, then unfurl into full-sized antennas. They allow satellite mission designers to obtain better performance across radio frequencies, while keeping down the mass and volume at launch. So how have things progressed in the last three years? First of all, we've seen success with our antennas, which we've now shipped and deployed. These are now helping connect everything…

They say that home is where the heart is, but is your home where the lights shine? Electric lighting has changed the way we live, and lighting technology has advanced to the point where we can now hold the power of thousands of candles in the palm of our hands. Artificial light at night (dubbed ‘ALAN’) has created its own empire in little over a century, and very few places are left on the globe that have escaped its growing, glowing campaign. Between 2012 and 2022, light pollution increased globally at a rate of 7–10 per cent each year. The situation is so dire that many places are now working to protect their night skies, such as the newly appointed Dark Sky Community of Presteigne and Norton in Wales, conquering…

Most of North America will be able to see partial phases of the 8 April solar eclipse (much of Alaska being the exception). However, only those in the narrow ‘path of totality’ get to see all the wonderful phenomena associated with a total solar eclipse. Getting close to this path will increase the percentage of eclipse you'll gre see, but this is nothing like the majesty of a full total. The path of totality has an average width of 185km and is around 16,000km long, though only 5,500km of that passes over land across North America. The total eclipse starts over the Pacific, the Moon's shadow racing northeast to make landfall just south of Mazatlán in Mexico at 11:07 MST (18:07 UTC). From there it tracks northeast to the point…

1. M13, the Great Cluster in Hercules 10x 50 As we approach the season for trying a Messier marathon, M13 reminds us why Charles Messier created his famous catalogue of objects not to be mistaken for comets. The great Hercules globular cluster lies one-third of the way down the western side of the Keystone asterism. In binoculars, it looks just like a comet, brightening towards the core. You might even be able to see it with your naked eye in very transparent skies. ☐ SEEN IT 2. Nu Coronae Borealis 10x 50 Nu (ν) Coronae Borealis appears as a double to your naked eye and is therefore easily split in small binoculars. The stars of this optical double (a chance line-of-sight pairing of stars that are not gravitationally bound) are…

Long ago, people thought that Earth was at the centre of the Universe. This ‘geocentric’ view was challenged as early as the third century by those who suggested that Earth and the other planets actually orbited the Sun. This new ‘heliocentric’ idea didn't really catch on until after Copernicus published the first mathematical model of a heliocentric model in 1514 and Galileo later expanded on his ideas. Later, astronomers would come to realise first that the Sun was merely one star in the Milky Way Galaxy, and then that the Milky Way itself was just one galaxy out of millions, making Earth and its inhabitants feel even less important in the grand scheme of things. The really bad news for geocentrists, then, is that our Solar System doesn't even lie…

Age: 4.57 billion years From looking at infant planets in other systems, we know that worlds form at the same time as their stars. Both the Sun and all of the planets of our Solar System originated in clouds of gas and dust known as stellar nurseries. Hydrogen comes together, forming a star and setting the dust spinning until it forms a disc. This ‘protoplanetary disc’ is where the planets form. To find the age of the Solar System, we need to find the age of the oldest things in it – specifically, the oldest rocks. These contain a tiny amount of radioactive material which decays over time to a daughter element. Geologists use this to do radiometric testing, where they look at the relative amount of the original element…

Age: Up to 13.8 billion years Strangely, it's far easier to predict how long a star is going to live than measure how long it has already existed. Most stars spend the vast majority of their lives in what's known as the main sequence phase. Main sequence stars have reached maturity and are steadily burning through the hydrogen within their cores. This era can last for billions of years, during which time they show little outward change. Our Sun, for instance, looks pretty much as it did a billion years ago. Stars only really change when they're very young or when they're approaching the end of their lives – which is why astronomers look towards dying stars when trying to measure stellar ages. How long a star lives depends on…

Modern astrophotography cameras are technical marvels that produce exquisitely detailed and colourful images. However, they remain at the mercy of Mother Nature. Cameras designed for deep-sky imaging need to capture long exposures, and to help combat the thermal noise generated during this process they are equipped with Peltier cooling modules that cool the sensor down to 20°C or more below the ambient temperature. However, if moisture is present, ice crystals can form on the sensor's surface. These appear as irregular black dots or as condensation on the protective glass in front of the sensor. Both will ruin image quality, but worse, the moisture threatens to damage the pin connections on the sensor. To combat these issues, many sensors are installed in a sealed chamber, with moisture kept at bay with…

VITAL STATS • Price £185 each (for sizes 5mm –20mm), £195 each (for 25mm and 30mm) • Focal lengths 5mm, 7.5mm, 10mm, 12.5mm, 15mm, 20mm, 25mm, 30mm • Lens design Ortho Plössl • Apparent field of view 53° • Eye relief 4mm, 5mm, 7mm, 8mm, 9mm, 13mm, 16mm, 19mm • Optical elements 5 • Extras Dust caps, filter thread • Weight 60g, 70g, 80g, 90g, 100g, 120g, 115g, 140g • Supplier First Light Optics • Email questions@firstlightoptics.com • www.firstlightoptics.com Eyepieces are something of a personal choice. Differences in eyesight and even variations in pupil diameter mean that what works for one person might not work for another. Every astronomer, however, should have a selection of low- and higher-powered eyepieces in their arsenal. Masuyama's offering of 53° eyepieces covers an excellent…