Indholdsfortegnelse for July 2021 i BBC Sky at Night

Get too close to a black hole and you’d reach a point of no return – the event horizon – past which you’d have to travel faster than the speed of light to escape its clutches. Or so the theory goes. As Colin Stuart explains in his feature this month, the event horizon is also a point of convenience which clothes over what we can’t explain, how space and time cease to exist at the ultimate end point of a black hole, the singularity. Turn to page 28 to read how new theories are suggesting ways in which black holes could exist without an event horizon, and how these theories can be tested. As we look forward to the midsummer months without truly dark nights, it might be nice to…

Melissa Brobby Amateur astronomer “I’ve enjoyed writing about the Space Shuttle because it was a wonderful way to relive what was, for me, an exciting era in human spaceflight.” Melissa celebrates the 10th anniversary of the last Shuttle flight, page 72 Scott Levine Naked-eye observer “Stargazing in summer is tough, but I love lying in the grass and watching the Summer Triangle arrive through the twilight and waiting for the night to fall.” Scott takes a twilight tour of the summer night sky, page 34 Colin Stuart Astronomer “I love writing about black holes – even though we can’t see them. They help light the way towards new and exciting theories in physics!” Colin explores new research into naked black holes, page 28…

Email your queries to scopedoctor@skyatnightmagazine.com I have a Sky-Watcher 150 Dobsonian. How and when should I clean the primary mirror? TONY WRIGHT The key to cleaning a telescope mirror is don’t, unless it is absolutely necessary! You need a lot of contamination for it to have any effect on the view. If and when the time does come, perhaps because of a dead insect or similar issue contaminating the surface, then proceed carefully. Remove the mirror from its mirror cell and soak it in a plastic bowl with tepid water and a few drops of washing-up liquid for about five minutes to loosen the dust and other particles. Then remove the mirror and stand it on its side safely. Replenish the water in the bowl with fresh water and a…

DON’T MISS THIN MOONS BEST TIME TO SEE: 8 & 9 July (morning sky before sunrise) 10 July (evening sky after sunset) There are several well-timed opportunities for spotting thin Moons this year – waxing or waning lunar crescents seen close to the Moon’s new phase. At new Moon, the Moon lines up with the Sun when seen from Earth – technically they have the same ecliptic longitude. The ecliptic is that great circle centred on Earth which represents our planet’s orbital plane projected onto the sky. It also describes the path of the Sun against the background stars. The zero point for ecliptic longitude is called the ‘first point of Aries’ and it’s marked by the intersection of the ecliptic and the celestial equator. The Sun is positioned here…

Bullialdus Type: Crater Size: 61km Longitude/Latitude: 22.3°W, 20.7°S Age: 1.1-3.2 billion years Best time to see: Two days after first quarter (19 July) or one day after last quarter (3 & 4 July) Minimum equipment: 50mm telescope Bullialdus is a superb example of an impact crater. It sits within the western regions of 750 km Mare Nubium and appears largely surrounded by dark, solidified lava. The closest neijhbour is 26km Bullialdus A, which sits immediately south-southeast of Bullialdus, the rims of both features virtually touching. Apart from that, 61km Bullialdus is clear of any real intrusions, allowing it to appear framed in all its glory. The crater is extremely well preserved, with an appearance that is reminiscent of the impressive form of 93km Copernicus further to the north. The comparison…

26 July 13:34* The crew blast off from Cape Kennedy 26 July 16:56 The Lunar Module detaches from the Command Module, turns around and redocks, ready to travel to the Moon 29 July 20:05 Apollo 15 reaches lunar orbit 30 July 18:13 The Lunar Module departs from the Command Module, heading for the Moon 30 July 22:16 The Lunar Module touches down on the Moon’s surface 31 July 00:16 Scott opens the Lunar Module’s top hatch and surveys the landing site, closing the hatch 33 minutes later 31 July 13:13 First EVA commences, lasting 6 hours, 32 minutes 1 August 11:48 Second EVA begins, lasting 7 hours, 12 minutes 2 August 8:52 Final EVA begins, lasting 4 hours, 49 minutes 2 August 17:11 The Lunar Module launches from the lunar…

Practical astronomy projects for every level of expertise A highlight of summer nights is seeing the Milky Way stretching across the sky. Its name is a translation of the Latin via lactea, meaning ‘milky road’, which perfectly describes its appearance from Earth. Over the centuries our knowledge of the Milky Way has changed considerably. It wasn’t until Galileo pointed his telescope at the Milky Way that we discovered that it’s made up of individual stars; and it was believed for ages that it contained all the stars in the Universe, with our Sun at its centre. Next, in the 1920s, the Milky Way was found to be one of many galaxies. Visually, we could see that it must be a flattened disc of stars, but other details were still a…

More ONLINE A gallery containing these and more of your images The Leo Triplet Peter Rea, Appley Bridge, Wigan, 16 March 2021 Peter says: “I took up astrophotography six months ago. This was taken from my back garden on one of those rare nights in the UK when it was clear all night. I was pleased with the level of detail that came through from just 4.5 hours of imaging time.” Equipment: ZWO ASI 533MC Pro cooled colour camera, Altair 72mm EDF refractor, Sky-Watcher HEQ5 mount Exposure: 69x 240’ Software: APP, Affinity Photo Paul’s top tips: “As I’m just starting out in astrophotography, my advice is to get the basics right. Set up in daylight if possible, taking your time to make sure the balance of the scope is correct…

With Glenn Dawes When to use this chart 1 July at 00:00 AEST (14:00 UT) 15 July at 23:00 AEST (13:00 UT) 31 July at 22:00 AEST (12:00 UT) The chart accurately matches the sky on the dates and times shown for Sydney, Australia. The sky is different at other times as the stars crossing it set four minutes earlier each night. JULY HIGHLIGHTS To catch a dance between Venus and Mars, try looking one hour after sunset in the early evening sky. Venus passes Mars on the 13th, when they appear just 0.5° apart. The night before (the 12th) sees the thin crescent Moon 4.5° below the pair. Fortunately, the glare of Venus makes it easy to tell the planets apart. The ‘goddess of love’ outruns Mars, passing Regulus…

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With four active robots on the surface, and a fleet of orbiting spacecraft, the Red Planet is coming under scrutiny like never before. The most exciting results come when different observations can be tied together. Volcanic activity – like the kind that the team found using data from NASA’s Mars Reconnaissance Orbiter – might fit in with the observation from the Curiosity rover of ‘burps’ of methane, and its possible presence in the atmosphere. Methane, which might be produced by volcanic activity or maybe just by biological processes, is the primary target for the European Space Agency’s Trace Gas Orbiter, though it has so far drawn a blank. Chris Lintott co-presents The Sky at Night…

Who doesn’t love summer? School’s out and it’s the time of year for camping trips and beach holidays! Plus, the long days mean there’s time for another ice cream as we watch the day melt into a sunset. Extra sprinkles, please. Late sunsets mean night falls later, too. But, while the kids aren’t in school, us adults still have to get up for work. In the UK, the Sun doesn’t set until after 21:00 BST (20:00 UT), and the last drops of sunlight don’t leave the sky until midnight. So there isn’t much true night when we’re this close to June’s summer solstice, but there’s plenty of sky-watching we can do, especially if we start earlier, during evening’s twilight. So much can be seen as the Sun begins to set…

J-P Metsavainio is a Finnish visual artist and astrophotographer My work is an endless curiosity: I love to see and show how wonderful our Universe really is. Our Galaxy may be one of many billions in the Universe, but it’s our home. This makes it special not just to me, but all of us on Earth. It’s important to know what’s going on in our cosmic backyard, and before I created this mosaic there was no image like it that I knew of. I’m thrilled about all the details I managed to get from the emission nebulae in this mosaic, which also contains several supernova remnants seen for the first time in their full glory. Astrophotography is one of the most difficult forms of nature photography. Exposure times are long,…

Saturn is approaching a time that is optimal for viewing and although it appears low when it’s viewed from the UK, a small telescope will show its rings. Locate Saturn rising above the southeast horizon as darkness falls; brighter Jupiter can be seen rising around 50 minutes later. Allow Saturn to gain some height above the horizon and then centre it in your field of view. A minimum magnification of 25x will show the rings extending either side of the main globe, while magnifications of 50x to 75x will give a sense that the rings are actually circling the planet. www.bbc.co.uk/cbeebies/shows/stargazing…

Pluto is the planet that lost its planetary status in August 2006. With the increasing number of large bodies discovered in the outer Solar System, the International Astronomical Union (IAU) faced a problem. Should these objects be classified as planets too? In the end the IAU redefined what it means to be a planet and Pluto didn’t make the grade. However, it did become the largest member of a new class of objects known as ‘dwarf planets’. Reaching opposition this month, dwarf planet Pluto makes a great subject for our monthly challenge. Pluto reaches opposition on 17 July and while technically within the boundary of the faint star-rich constellation of Sagittarius, the Archer, it is now located east of the Milky Way’s core region in a relatively barren area of…

Charlotte Daniels is an amateur astronomer, astrophotographer and journalist There are many branches of astrophotography to explore, from capturing the Moon’s craters, to widefield starscapes of our Milky Way. But perhaps the most demanding images to take are those of deep-sky objects. Deep-sky photography includes images of nebulae, galaxies and star clusters, and whether you’re a seasoned daytime photographer or a complete beginner, doing justice to these faint fuzzy targets takes time and patience. However, practice makes perfect and deep-sky photography is extremely rewarding right from the word go: you can image a target and unlock details that are simply invisible to visual astronomers. With a bit of practice, amateur astrophotographers can capture images of the deep sky that are reminiscent of the Hubble Space Telescope. If you’re curious about…

Colliding Worlds Simone Marchi Oxford University Press £20 • HB The formation of planets is often glossed over in popular science, not because it’s uninteresting, but because our understanding of its detail has only developed relatively recently. In Colliding Worlds, Simone Marchi explores this most tumultuous period in the Solar System’s history. Along the way we learn more about – as the book’s subtitle suggests – “how cosmic encounters shaped planets and life”. This is clearly a book written by an expert in the field, with a few mentions of the author’s own research where relevant. There is good depth of explanation around our current understanding, describing subtle areas of disagreement between competing theories. While technical terms are generally explained clearly and concisely, there’s no shying away from relatively complex…

Television Find out what The Sky at Night team have been exploring in recent and past episodes on page 18 Online Visit our website for competitions, astrophoto galleries, observing guides and more Social media Follow us on Twitter, Facebook and Instagram for space news, astro images and website updates Podcasts Listen to our Radio Astronomy podcasts where the magazine team and guests discuss astro news Tablet/phone Get each month’s issue on your Apple or Android device, now with bonus image galleries eNewsletter The best targets to observe each week, delivered to your inbox. Visit bit.ly/skynewsletter Find out more at: www.skyatnightmagazine.com…

On the 20 July 1977 episode, Patrick took a look at a new British telescope being built in Hawaii, which we now know as the United Kingdom Infrared Telescope (UKIRT). Construction began in 1975, but it wasn’t until 1979 that the telescope’s 3.8m-wide primary mirror saw first light. Although ending up in Hawaii, the telescope’s optics were made in Newcastle while much of its infrastructure was created in Sheffield. Unfortunately, neither location is well known for the cloud-free skies astronomy demands, and so the final telescope was constructed in Hawaii. As the infrared light that the telescope would look for is rapidly absorbed by the atmosphere, it was built on top of Mauna Kea at an elevation of 4,200m, above most of Earth’s atmosphere. UKIRT was and remains one of…

PHILIP’S The ‘Message of the Month’ writer will receive a bundle of four top titles courtesy of astronomy publisher Philip’s: Ian Ridpath and Wil Tirion’s Star Chart, Robin Scagell’s Guide to the Northern Constellations, Heather Couper and Nigel Henbest’s 2021 Stargazing, and a planisphere for the night skies as they appear at latitude 51.5° north. Winner’s details will be passed on to Octopus Publishing to fulfil the prize MESSAGE OF THE MONTH A new hobby in lockdown Around the time of the first lockdown last year I turned 18 and the situation lent itself well to waking up at lunchtime and going to bed at dawn. This, along with the hours spent in the garden longing to leave the house, created the perfect conditions for astrophotography. I discovered my love…

The idea of a black hole is older than many people realise. As far back as the 18th century, Englishman John Michell (pictured, right) wondered whether you could add enough mass to the Sun so that light wouldn’t be able to leave its gravitational clutches. The first modern incarnation of a black hole appeared in a 1939 paper by Robert Oppenheimer, the famed leader of the Manhattan Project. Called On Continued Gravitational Contraction, Oppenheimer speculated that if the core of a collapsing star has sufficient mass it would become what we now call a black hole. The phrase ‘black hole’ itself wouldn’t appear for another three decades: it was coined by John Wheeler in 1967. Circumstantial evidence for their existence arrived in the 1970s when astronomers saw intense X-ray radiation…

16-PAGE CENTRE PULLOUT THREE SHADOW TRANSITS! Observe the shadows cast on Jupiter’s atmosphere by Ganymede, Callisto and Io LUNAR LETTERS Spot the clair-obscur effects that reveal an ‘X’ and a ‘V’ on the Moon FINDING PLUTO Can you track down and image the dwarf planet? About the writers Astronomy expert Pete Lawrence is a skilled astro imager and a presenter on The Sky at Night monthly on BBC Four Steve Tonkin is a binocular observer. Find his tour of the best sights for both eyes on page 54 Also on view this month… ✦ An evening conjunction of Mars and Venus ✦ Noctilucent clouds, and how to spot them ✦ A thin crescent Moon with Mercury, then Venus Red light friendly To preserve your night vision, this Sky Guide can…

Universal time (UT) and British Summer Time (BST) Universal Time (UT) is the standard time used by astronomers around the world. British Summer Time (BST) is one hour ahead of UT RA (Right ascension) and dec. (declination) These coordinates are the night sky’s equivalent of longitude and latitude, describing where an object is on the celestial ‘globe’ Family friendly Objects marked with this icon are perfect for showing to children Naked eye Allow 20 minutes for your eyes to become dark-adapted Photo opp Use a CCD, planetary camera or standard DSLR Binoculars 10×50 recommended Small/medium scope Reflector/SCT under 6 inches, refractor under 4 inches Large scope Reflector/SCT over 6 inches, refractor over 4 inches GETTING STARTED IN ASTRONOMY If you’re new to astronomy, you’ll find two essential reads on our…

KEY TO STAR CHARTS When to use this chart 1 July at 01:00 BST 15 July at 00:00 BST 31 July at 23:00 BST On other dates, stars will be in slightly different positions because of Earth’s orbital motion. Stars that cross the sky will set in the west four minutes earlier each night. How to use this chart 1. Hold the chart so the direction you’re facing is at the bottom. 2. The lower half of the chart shows the sky ahead of you. 3. The centre of the chart is the point directly over your head. Sunrise/sunset in July* Date 1 Jul 2021 11 Jul 2021 21 Jul 2021 31 Jul 2021 Sunrise 04:46 BST 04:56 BST 05:09 BST 05:24 BST Sunset 21:42 BST 21:35 BST 21:23 BST…

1 M8 M8, or the Lagoon Nebula, together with its embedded cluster (NGC 6530), is compromised by a low altitude from the UK. M8 is easy to locate, 6° north of Alnasl (Gamma (γ) Sagittarii), the star marking the lip of the Teapot asterism’s spout. At mag. +4.6, the Lagoon is visible to the naked eye and an easy target for a 150mm scope. It looks divided – a bright condensed nebula separated from its associated star cluster by a dark lane. A few bright stars can be seen in the nebula’s bright part and a hint of nebulosity can be seen all over the cluster. □ SEEN IT 2 M20 020, the Trifid Nebula, lies 1.4° north and 0.3° west of M8. It shines with an integrated magnitude of…

Commander: David Scott A former Air Force test pilot, Scott joined NASA in 1963. He flew on Gemini 8 alongside Neil Armstrong, and during Apollo 9 he piloted the Command Module while his colleagues took the Lunar Module on a test flight. He later worked on the Apollo-Soyuz project and was director of NASA’s Dryden Flight Research Center. Lunar Module pilot: James Irwin Before joining NASA in 1966, Irwin was a military test pilot. He left NASA shortly after Apollo 15; he’d found the trip a religious experience and it inspired him to set up the evangelical High Flight Foundation. Under its banner, he mounted expeditions to find the remains of Noah’s Ark on Mount Ararat. He died on 8 August 1991 aged 61. Command Module pilot: Alfred Worden Previously…

The fundamentals of astronomy for beginners This month marks the 10th anniversary of NASA’s last Space Shuttle flight: on 21 July 2011 the landing of Shuttle Atlantis bought three decades of the Space Shuttle programme to a close after 135 missions. The Space Shuttles may be permanently grounded, but many historic achievements were made possible by their existence. When Space Shuttle Columbia lifted off in 1981, piloted by Apollo astronaut John Young and rookie Bob Crippen, it signalled the start of NASA’s Space Shuttle programme and the spacecraft became a regular presence in space, launching and repairing satellites while in orbit. Many famous firsts were achieved thanks to the ambitious Shuttle programme, including the launch of the first American woman in space, Sally Ride (in 1983); NASA’s first female Shuttle…

Simone Marchi How can we know what the early Solar System was like? The Moon has lots of impact craters, which tell us that in the early Solar System it was subjected to an intense flux of collisions that shaped the lunar landscape. And we see that not just on the Moon: thanks to space exploration we have visited other planets in the Solar System, other satellites and asteroids. Everywhere we find a rocky surface, we see impact craters. This suggests that in the young Solar System, collision rates were much higher than today. Why are space rocks of such interest? Earth and the other planets formed from a disc of debris - smaller asteroids - that accreted over time. As that happened, those objects were altered: pristine materials were…

1 Celestron lens cleaning kit Price £14.99 • Supplier Harrison Telescopes Tel 01322 403407 • www.harrisontelescopes.co.uk Safely remove Gust, Girt and fingerprints from your optics with this cleaning kit. It comes with a bottle of cleaning solution, a lens brush, a cleaning cloth and 10 lens wipes, all in a convenient carry pouch. 2 Altair 100mm ultra-light guidescope rings Price £99.50 • Supplier Altair Astro Tel 01263 731505 • www.altairastro.com The design of these rings means they can maintain a secure grip on your guidescope and remain lightweight. The anodised, stainless steel components will also leave your setup rust-free, and will fit guidescopes with an outer diameter between 45mm and 80mm. 3 Mars exploration crew jacket Price £120 • Supplier Science Museum https://shop.sciencemuseum.org.uk Prepare for launch and get ready for…