Indholdsfortegnelse for September 2021 i BBC Sky at Night

When Galileo recorded his magnified observations of the Moon and the planets with a modified new Dutch invention, the telescope, he could hardly have foreseen the revolution in understanding he had set in motion. Today, a little over 400 years since the Galilean moons were first observed, the telescope has enabled us to see beyond the visible spectrum and back to the primordial cosmos. Turn to page 26 to read Ezzy Pearson’s celebration of the instruments that have perhaps done most to widen the boundaries of our understanding. It’s worth training your own telescope on the skies this month as the nights start to lengthen. On page 32, Scott Levine looks at the dark-sky season to preview the treats that lie in store for binocular and naked-eye stargazers, as well…

Mary McIntyre Outreach astronomer “This model was great fun to build. I have never seen our nearest stellar neighbours presented in this way before and I love the final result.”Mary builds a 3D model of our Sun and its closest stellar neighbours, page 74 Govert Schilling Astronomy journalist “I love the Einstein Telescope, as there’s a chance that this gravitational wave observatory will be built in my home country: the Netherlands!”Govert reports on how astronomers will monitor black hole collisions, page 62 Hayley Smith Space educator “Groundbreaking scientific discoveries, upcoming Moon and Mars missions... Space is an exciting industry to be part of.” Hayley advises prospective GCSE and A-Level students aiming for the stars, page 36…

Sky at Night: Question Time This month’s episode is a one-hour special filmed live from the Civic Theatre in Chelmsford as part of the 2021 British Science Festival. Maggie, Chris, Pete and a panel of special guests and astronomy experts take to the stage in front of a studio audience to answer questions about the mysteries of the Universe and provide practical observing advice. BBC Four, 12 September, 10pm (first repeat BBC Four, 16 September, 7:30pm) Check www.bbc.co.uk/skyatnight for more up-to-date information…

Email your queries toscopedoctor@skyatnightmagazine.com I have a Sky-Watcher 200PDS and 250PDS Newtonian reflector, and an Altair Hypercam 290C and 183C camera. I tried to take a filtered image of the Sun, but couldn’t capture the whole disc. Would a focal reducer help me get it all?COLIN ANDERSON The short answer is no! There are two main issues that make using a focal reducer on a Newtonian reflector unsuitable: the difficulty in obtaining focus with a camera, and the generation of elongated star shapes towards the edge of the increased field of view. Newtonian reflectors are renowned for their short back-focus, which makes focusing tricky, if not impossible, to achieve on some instruments as the focus tube simply cannot be moved in far enough. Your two Newtonians are DS versions, which…

Over 400 years ago in 1608, Dutch optician Hans Lippershey filed a patent for his new invention, the refracting telescope. Astronomy would never be the same again. In the centuries since, telescopes have helped us glimpse the farthest reaches of the Universe and begin to unpick its secrets. From the personal telescopes Galileo and Newton kept in their observatories, to the colossal telescopes that have to be built into the sides of mountains, we take a look at the instruments that have made – or hope to make – the biggest impacts in the held of astronomy… GALILEO’S TELESCOPE The Italian astronomer was the first to systematically map the heavens In May 1609, Galileo Galilei learned of a remarkable new invention from the Netherlands that used lenses to make distant…

The start of autumn in the Northern Hemisphere is just a matter of weeks away, but we can already see the nights getting longer, with sunsets now over an hour and a half earlier than they were around the June solstice. As these earlier nights for observing come along, let’s look at the exciting sights we can look forward to seeing as the dark-sky season begins. September With September here, the long summery days are gradually changing into early nights. Indeed, we’ll see spring and summer’s stars making way for the dark-sky season as autumn approaches. Let’s begin our dark-sky adventure at a well-known asterism, the Plough, sitting upright just above the northern horizon. The next bright star to its south-southeast is Arcturus (Alpha (α) Boötis), which we usually think…

HUNT FOR THE SLENDER MOON Two excellent opportunities this month, thanks to a good phase and position MINOR PLANET AHOY Observe asteroid 2 Pallas as it reaches opposition in Pisces LOCATE A ‘LUNAR CITY’ Spot the streets of Gruithuisen’s imaginary metropolis 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... ♦ Shadow transits by Jupiter’s Galilean moons ♦ Mercury at greatest eastern elongation ♦ A conjunction of Jupiter, Saturn and the Moon Red light friendly To preserve your night vision, this Sky Guide can be read using a red light under…

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 10x50 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…

When to use this chart 1 September at 01:00 BST 15 September at 00:00 BST 30 September 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 September* Moonrise in September* Moonrise times 1 Sep 2021, --:-- BST 5 Sep 2021, 03:48 BST 9 Sep 2021, 09:23 BST 13 Sep 2021, 15:13 BST 17 Sep 2021, 18:44 BST 21 Sep 2021,…

1 NGC 14 The Great Square of Pegasus is a large distorted ‘square’ asterism formed from Markab, Scheat and Algenib in Pegasus (Alpha (a)), Beta (‘)) and Gamma (y) Pegasi respectively) along with Alpheratz (Alpha (a) Andromedae). We’ll start with the faint but easy to locate irregular galaxy NGC 14. It has an apparent magnitude of +12.7, but is diffuse. At a distance of 47.1 million lightyears, it appears as little more than a faint smudge. It’s located 1.25° northwest of Algenib and has an apparent size of 2.0 x 1.3 arcminutes, the elongated dimension orientated in a north-northeast/south-southwest direction. □ SEEN IT 2 NGC 7814 I Our next target sits 1.4° west-northwest of NGC 14, or if you had trouble with that galaxy, 2.6° west-northwest of Algenib. It also…

Find out more about how we test equipment at www.skyatnightmagazine.com/scoring-categories HOW WE RATE Each product we review is rated for performance in five categories. Here’s what the ratings mean: ★★★★★ Outstanding ★★★★☆ Very good ★★★☆☆ Good ★★☆☆☆ Average ★☆☆☆☆ Poor/avoid PLUS: Books on the big cosmological questions and the Space Race, plus a roundup of essential astronomy gear SUBSCRIBE Discover the best new kit each month…

What’s Eating the Universe? Paul Davies Allen Lane £16.99 • HB It is little more than a century since the nature of gravitation, the abstractness of the quantum world and the true extent of the Universe were first perceived. But in that short time, the progress in our cosmological understanding has been staggering. We have deciphered the earliest moments and subsequent history of the Universe to such an extent that our insights about the origins of our own planet pale in comparison. Although this insight has been astounding, there are of course many mysteries still occupying modern astrophysics and cosmology. In this rather short book, cosmologist Paul Davies takes us on a whistle-stop tour of some of these solved and not-so-solved topics. He propels us across the development of post-Einsteinian…

1 Celestron Ultima Edge flat field 1.25-inch eyepieces Price from £129 • Supplier Harrison Telescope Tel 01322 403407 • www.harrisontelescopes.co.uk ADVANCED These eyepieces give a sharp, clear image – from the centre to the edge of the wide field of view. Available in 10mm, 15mm, 18mm, 24mm and 30mm focal lengths. 2 Astro Engineering Rigid 8-inch dew shield Price £56.90 • Supplier Telescope House Tel 01342 837098 • www.telescopehouse.com Clear the dew away from your optics and protect your observations from stray light with this shield. It fits around tubes with a diameter between 243mm and 253mm, and it’s held in place with nylon screws. 3 StellarMira 2-inch Field-Flattener with M42 adaptor Price £79 • Supplier First Light Optics Tel 020 3384 5187 • www.firstligKtoptics.com Remove the curvature of your…

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The first images taken with Hubble’s restored cameras were of two unusual galaxies, as part of a survey of irregular systems led by Julianne Dalcanton. Earlier this year observations made with Hubble revealed the surprising extent of Andromeda’s gaseous halo and that quasars have been captured in its deep fields. Closer to home, planetary nebulae and stars have been scrutinised by the space telescope. This variety is why everyone is so relieved to have Hubble back. It’s a supremely multipurpose instrument, as capable of contributing to cosmology as astrobiology. Let’s hope there’s plenty more life in the old scope yet. Chris Lintott co-presents The Sky at Night…

Email us at inbox@skyatnightmagazine.com Tweet Lar McCarthy @parsec98 • 19 Jul The Dumbbell Nebula, M27, taken from my backyard #observatory in #Cork #Ireland with a @Celestron C11 CGEM and a @zwoasi 1600MM Pro Cool through Ha and Olll Alters. @CorkAstronomy @ AstronomyIRL @AstronomyMag @skyatnightmag Different views I’m no scientist but two articles in the July 2021 issue appear to contradict each other. On page 9 in ‘Eye on the Sky’ the ‘We’re nothing special’ caption states that observations of spiral galaxies like our own lead scientists to conclude that the Milky Way, “...evolved peacefully over eons,” and “.didn’t come about because of a gigantic mash-up.” But on page 11 in ‘Bulletin’, the ‘Stolen stars’ story explains that several of the oldest giant red stars in our Galaxy “.originally belonged to…

Wednesday 1 A telescopic view of Jupiter this morning will reveal the outer Galilean moon, Callisto, transiting the planet’s disc from 02:33 BST (01:33 UT). Jupiter sets before the transit ends. See page 47 for more. Thursday 2 This morning’s 24%-lit waning crescent Moon occults mag. +3.0 Mebsuta (Epsilon (ɛ) Geminorum) from 01:12 BST (00:12 UT) until 02:04 BST (01:04 UT). These times are correct for the centre of the UK and will vary slightly with location. Friday 3 This morning’s 16%-lit waning crescent Moon occults mag. +3.6 Kappa (k) Geminorum from 03:41 BST (02:41 UT) until 04:38 BST (03:38 UT). Saturday 4 This morning’s 9%-lit waning lunar crescent is just 2.6° from the Beehive Cluster, M44, at 04:10 BST (03:10 UT). Sunday 5 Catch two good transits by Jupiter’s…

DON’T MISS THE MOON BEST TIME TO SEE: Multiple events, dates and times as specified The Moon puts on a fine display of varied events during September. On the morning of the 2nd, starting at 01:12 BST (00:12 UT), the 24%-lit waning crescent Moon occults mag. +3.0 Mebsuta (Epsilon (e) Geminorum) – when the Moon’s position hides our view of the star from Earth. The star’s reappearance occurs around 02:04 BST (01:04 UT), as viewed from centre of the UK, although times will vary slightly with location. On the morning of the 3rd, mag. +3.6 Kappa (g) Geminorum is occulted by the now 16%-lit waning crescent Moon. Viewed from the centre of the UK, it disappears at 03:41 BST (02:41 UT), and reappears at 04:38 BST (03:38 UT) in morning…

Billy Type: Crater Size: 46km Longitude/Latitude: 50.2°W, 13.8°S Age: 3.2–3.9 billion years Best time to see: Four days after first quarter (18 September) or three days after last quarter (3 September) Minimum equipment: 50mm telescope Located on the southern shore of Oceanus Procellarum, crater Billy may be only 46km in diameter but it has presence due to its dark, lava-filled floor. To the north and slightly zest of Billy is 45km Hansteen a crater of similar size but completely different appearance. Where Billy’s floor has been completely smoothed over by lava, Hansteen’s remains faithful to the original impact and appears rough, covered in a series of concentric rings infilled with hills. At times of oblique illumination, Billy’s 1.3km-high rim casts its shadoz across the crater’s floor, the dark fat lava…

Would you consider buying a telescope that doesn’t have an eyepiece? On the face of it, Unistellar’s eVscope eQuinox appears to challenge conventional wisdom by not including one, so we were keen to put it to the test. When Go-To telescopes arrived 20 years ago they were hugely divisive; amateurs who had spent years learning their way around the sky felt cheated that anyone could now access the same deep-sky gems instantly. But it’s now rare to find a telescope without Go-To capability – and the hobby has blossomed. The Unistellar eVscope eQuinox is the latest version of the ‘smart’ digital telescope and is just as innovative. Like the original eVscope from 2020, the eVscope eQuinox is a 4.5-inch, f/4 reflector that comes with a camera sensor that tracks and…

Welcome Mercury back to the evening skies and discover celestial treasures in Grus, the Crane When to use this chart 1 Sep at 00:00 AEST (14:00 UT) 15 Sep at 23:00 AEST (13:00 UT) 30 Sep 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. SEPTEMBER HIGHLIGHTS September sees the best return of Mercury to the evening skies for 2021. This elusive world is rarely visible outside twilight hours, but mid-month is placed 10° above the western horizon at the end of astronomical twilight. Travelling with the bright star Spica (Alpha (α) Virginis) for the last two weeks, Mercury is located…

Television Find out what The Sky at Night team have been exploring in recent and past episodes on page 16 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…

ESA rover ready An upgraded parachute to enable the British-built Rosalind Franklin rover to land safely on Mars has passed its high-altitude tests, meaning the rover should be ready for launch in 2022. Problems with the original 35m-wide parachutes caused a delay. Alien artefact search A group of astronomers have announced a new endeavour, the Galileo Project, to hunt for extraterrestrial technological civilisations (ETCs). The project will search for physical artefacts from ETCs, including interstellar objects, such as ‘Oumuamua which passed through the Solar System in 2017. Gamma ray burst fires on queue An unusual type of star, known as a gamma repeater, emitted its first burst after three months of inactivity on 24 June, as predicted. If it follows the pattern seen so far, the star (SGR 1935+2154) will…

On 19 September 1957, Patrick Moore was joined on The Sky at Night by 15-year-old Clive Hare, who had been the first person in the UK to spot a new bright comet – Comet Mrkos. In April and May 1957, Comet Arend-Roland – the first naked-eye comet in several decades – had been streaming across the night sky. Now faded from view, astronomers assumed there would be a long wait for the next. But then, just a few months later on the morning of 29 July 1957, Japanese astronomer Sukehiro Kuragano spotted what appeared to be another comet streaming across the sky. A few days afterwards pilot Peter Cherbak also spotted the same object while flying over Nebraska. Unfortunately, both were delayed from reporting their discoveries and so the credit…

About two years, while on a night shift, one of my colleagues showed me two dots in the sky, which turned out to be Jupiter and Saturn. At that moment I realised how much is actually in the night sky and that inspired me to see what else was out there. A few weeks later I bought my first telescope and I got hooked on stargazing after looking at the Moon. (It also made me look into many of the space missions, including Apollo, Voyager and Cassini.) It amazes me that something so far away can be seen so large and in so much detail; it really puts into perspective how small we are and how far away everything is. I can’t wait until Jupiter and Saturn come back around…

In the early days of astronomy, any budding stargazer had one huge hurdle to overcome: getting a telescope. For centuries, the only way to acquire one was to either buy an expensive, hand-made model from a master telescope maker, or spend hours laboriously grinding lenses or mirrors to make your own. It was the latter approach Tom Johnson took when he introduced his sons to stargazing in America in the late 1950s. As he worked on the project, Johnson became more and more convinced there was an easier way to make telescopes. Just like Sir Isaac Newton, he was using easy-to-craft spherical mirrors, but using a Schmidt corrector plate to remove the spherical aberrations. Invented by Bernhard Schmidt in 1930, this was a glass plate positioned across the opening of…

The ‘Lunar X’ and ‘Lunar V’ are examples of clair-obscur effects; tricks of light and shadow which creates familiar shapes. In this case, it’s the letters X and V that appear along the line dividing light and dark on the Moon’s globe – the terminator. Visible for just a few hours, both letters are best seen at 21:30 BST (20:30 UT) on 13 September, the ‘X’ roughly one-quarter up the terminator from the Moon’s southern edge, the ‘V’ slightly north of the mid-point. Using binoculars or a scope, can you see the letters suspended in the dark against the terminator? www.bbc.co.uk/cbeebies/shows/stargazing…

A casual look at the night sky gives the impression that the stars are constant and unchanging. While it’s true that many stars remain fairly constant over the course of a human lifetime, there’s a large number of stars that change quite rapidly, sometimes in a matter of hours. The ancient Egyptians knew that the star Algol (Beta (β) Persei) in Perseus changed in brightness, but it wasn’t until 1638 when Johannes Holwarda discovered that the apparent magnitude of the red giant star Mira (Omicron (o) Ceti) in the constellation of Cetus, the Whale varied over a period of about 11 months. Eventually, other stars with similar behaviour were discovered and, before long, a new area of astronomy arrived: the study of variable stars. Today, variable stars play an important…

For this fun project we create a three-dimensional model that shows where the nearest 20 stars to our Solar System are located. It places the Sun at its centre and gives you a unique perspective of our nearby stellar neighbourhood. It doesn’t just consider the distances of the stars, but gives their real coordinates relative to the orbital plane of the Solar System, which allows you to see exactly where the nearby stars lie relative to our Sun. We achieve all this by using basic materials and the project is packed with learning opportunities for your family. The stars are colour-coded depending on their spectral class, so you can discuss the differences between the classes and explain that although 76 per cent of stars in our stellar neighbourhood are ‘M…

What cosmological questions remain unsolved? Did the Universe originate a finite time ago, or has something always existed? Or, to express it more bluntly, did time itself begin with the Big Bang? What is the Cosmic Microwave Background (CMB)? It is the fading afterglow of the Big Bang. When the Universe erupted into existence 13.8 billion years ago, it was immensely hot. That heat radiation suffused all space, but as the Universe expanded, the temperature declined, so that today it forms a pervasive background of microwaves, like a vast cosmic oven. What might the ‘super-void’ be? Cosmologists are stumped. It looks like something banged into our Universe, which is a rather outlandish theory, but who knows? More conservatively, the simple picture we have of inflation – when the Universe jumped…