Indholdsfortegnelse for December 2021 i BBC Sky at Night

December night skies are long and dark – the ideal conditions for amateur astronomy. Orion’s commanding presence is visible from early evenings as the constellation rises, and on page 54 of this month’s Sky Guide, you’ll find Steve Tonkin’s binocular tour of the Hunter and some intriguing sights within. Many will know of Orion’s Belt, now it might be time to discover Orion’s Pelt too. Passing by Orion’s left shoulder you’ll find the Milky Way, the location of Stuart Atkinson’s midwinter tour on page 28. Here you’ll discover a different side to our Galaxy, not the gaseous nebulae of summer skies – we look out on a different part of the Milky Way in winter – but a host of sparkling star clusters that are a beautiful sight in binoculars…

NASA’s Mission Control now has plenty of time to work out what’s wrong with the Lucy mission’s recalcitrant solar panels – which have a collecting area of 51m2, but even if the probe has to make do with what it has, the fact it is now on its way to the Trojan asteroids should make it a success. Almost every spacecraft you can think of has had its share of trouble. Galileo had to function without the high gain antenna designed to transmit most of its data back to Earth, and Juno has remained in its parking orbit due to worries about its engines. Spirit kept rebooting its memory when it first landed on Mars, and even the Huygens probe nearly missed out on sending data back from Saturn’s moon…

Email us at inbox@skyatnightmagazine.com Emails – Letters – Tweets – Facebook – Instagram – Kit questions MESSAGE OF THE MONTH A vintage approach My solar disc images are fairly mediocre compared to many others I have seen over the years in the magazine, but it’s the method of capture that I thought might be of interest. Having a bit of an obsession with vintage optical tubery, I found myself acquiring a nice old telescope with a little history behind it. This tiny Maksutov-Cassegrain was manufactured by PZO in Poland around I960. If you went to school in East Germany during the Cold War, this is what you had to study with, and it was supplied from new with 50x and 90x eyepieces. If, however, you were schooled in the West,…

If you’ve ever wondered why the Milky Way looks so different in the winter compared to its appearance in the summer, it is because of our Solar System’s position within the great Catherine wheel of sparkling stars that is our Galaxy. When we look out from Earth on a clear night during the summer months we’re looking in towards the centre of the Milky Way, and also looking through one of its densely packed, nearby spiral arms, so we see a lot of stars – countless billions of them, in fact – looking like mist or smoke. In winter however, those parts of the Milky Way are hidden from us by the Sun and we’re looking outwards to where the stars are much less densely packed, so the Milky Way…

When you crush the mass of a star down to the size of a city you put the constituent material under extreme amounts of pressure. The neutrons get distorted into structures of different shapes. These structures are 10 Billion times stronger than steel, making them the strongest known material in the Universe. As they resemble different types of pasta, they have been named after the Italian foodstuff. Near the surface of the neutron star, this ‘nuclear pasta’ takes the form of bubbles called gnocchi. Go deeper and the growing pressure compacts the pasta into a shape more like spaghetti, and go deeper still and it is compressed into flat sheets of lasagne. Although anti-spaghetti and anti-gnocchi are not pre-pasta courses, there are materials inside neutron stars with holes shaped like…

Pallas Type: Crater Size: 50km Longitude/Latitude: 1.7° W, 5.5° N Age: Approximately 3.9 billion years Best time to see: First quarter (11-12 December) or six days after full Moon (25-26 December) Minimum equipment: 50mm refractor Pallas is an ancient lunar crater appearing close to the centre of the Moon’s disc as seen from Earth. The Moon’s equivalent to Earth’s prime meridian intersects the lunar equator in the dark 350 km lava bay known as Sinus Medii (‘central bay’). Fifty-kilometre Pallas is located in the rough highland region immediately north of Sinus Medii. Pallas is ancient and battered. It sits between two prominent craters which couldn’t be more apart in their appearance. To the north is bowl-shaped 18km Bode, a relatively young feature with a sharp, slightly non-circular crater rim. To…

Two dogs snap at the heels of the Ursa Major, the Great Bear, in a nightly chase around the north celestial pole. These canines are the hunting hounds of Boötes, the Herdsman, who holds them on a leash in his outstretched hand. In Greek tradition, Boötes was visualised in several ways, usually herding or driving animals. One story says that the name Boötes comes from the Greek for ox driver, since the stars of the Plough were visualised as an ox cart. An alternative explanation is that the name comes from a Greek word meaning ‘noisy’, and we can perhaps imagine the sounds of the herdsman shouting to his animals in the night. The two dogs of Boötes are represented by the constellation of Canes Venatici, but this isn’t one…

By the time you’re reading this story, NASA’s Lucy mission should be on its way to study the Trojan asteroids, having launched in October 2021. Trojans are asteroids that share Jupiter’s orbit around the Sun, either 60° ahead or 60° behind the giant planet. There’s thought to be at least a million of them larger than 1km in diameter. Launched on an Atlas V rocket, Lucy will perform gravity assist flybys with Earth in 2022 and 2023 to gain speed. In 2025, it will fly by the main belt asteroid 55246 Donaldjohanson, named after the paleoanthropologist who discovered the ‘Lucy’ hominin fossil after which the mission has been named. In 2027, Lucy will arrive in the ‘leading’ cloud of Trojans, studying four of them in detail. Next, a third gravity…

Mysterium Cosmographicum (‘The Cosmographic Mystery’), 1596 – the first published defence of the Copernican system, in which Kepler demonstrated his model of the planets using geometric shapes. Astronomia Nova (‘New Astronomy’), 1609 – contains his first and second laws of planetary motion. Harmonices Mundi (‘The Harmony of the World’), 1619 – contains his third law of planetary motion. Astronomiae Pars Optica (‘The Optical Part of Astronomy’), 1604 – Kepler’s exploration into eclipses, looking at the workings of light in reflection and refraction to explain astronomical phenomena. De Stella Nova (‘On The New Star’), 1606 – He wrote the book about the appearance of the supernova SN1604, also known as Kepler’s Nova.…

Our experts review the latest kit Small is beautiful, or so the saying goes, and the Acuter Voyager MAK80 certainly fits the description, even when it is still in its gift box. The instrument is a compact telescope and it is clearly well-suited for a wide range of activities, from nature and birdwatching to astronomy. For the purpose of this review, we are of course interested in discovering how well it performs for the latter. The MAK80 is an 80mm diameter Maksutov-design telescope. Inside its tube there is a combination of lenses and mirrors that fold the path of incoming light into a compact size. This means that the focal length of 800mm fits into a tubejust 270mm long. The 80mm primary mirror, combined with the focal length, gives a…

When did you catch the stargazing bug? I have always been fascinated by the night sky. From a very young age I can remember seeing the stars shining bright above me as my parents walked us home from my grandparents’ house. My interest grew through science fiction, especially Star Wars and Star Trek. Does social media particularly suit astronomy outreach? It’s one of the best ways of bringing astronomy to the masses. People can take as little or as much as they want. Teaching astronomy conventionally can sometimes be overwhelming for those with just a passing interest or who aren’t scientifically minded. What top tips would you give to beginner astronomers? Take your interest at your own pace, in a way that you enjoy. Follow some astronomy people on social…

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9 December 1966 On 9 December 1966 episode of the Sky at Night, Patrick Moore looked back at an unexpectedly spectacular astronomical event that had happened the previous month. The 18 November was the peak of the Leonid meteor shower, created by Earth passing through the trail of gravel-sized debris left behind in the wake of Comet 55P/Tempel-Tuttle. Most of the time, the meteor shower is one of the weaker showings of the year, with a zenithal hourly rate (ZHR) of just 10-15 meteors, but once every 33 or so years, it is a completely different story as the parent comet returns to the inner Solar System and refreshes the debris stream. In 1966, the comet had returned, and hopes were high about an impressive showing, at least for North…

Email your queries to scopedoctor@skyatnightmagazine.com I have a Sky-Watcher 200P Dobsonian telescope that appears to have mildew or mould on the primary mirror. Is this a big problem and should I clean the mirror? SAMUEL PARRY Cleaning a Newtonian reflector’s mirror should only be carried out if it is absolutely necessary. However, mildew and mould can damage the surface through chemical reactions so if you suspect their presence, cleaning the mirror correctly would be a good idea. This should never be done with a cloth but with the gentle action of water. Start by carefully removing the mirror from its mounting cell and place it in a plastic bowl full of tepid water and two drops of mild detergent. Leave to soak for five minutes and rinse under tepid running…

Almost every issue of BBC Sky at Night Magazine features at least one gorgeous image of the bright summer Milky Way, some taken with just mobile phones. If you want to photograph the winter Milky Way however, you’ll need a digital SLR camera on a tripod or a tracking mount, because it’s much fainter than its summer counterpart, and too faint and diffuse for most phone cameras to pick up. Fit your camera with a wide-angle lens, set it to an ISO of 800 or higher, point it towards Orion, the Hunter and then nudge it to the left so Orion is on the right of the frame. Using a cable release to reduce vibrations, take the longest exposure you can get away with before the stars trail or your…

DECEMBER 2021 PARADE OF THE PLANETS View six planets together in the evening sky at the end of the month POWER SHOWER Observe a peak display of Geminid meteors in the early hours RETURN OF THE COMETS Catch Comet C/2021 A1 Leonard among December’s icy visitors 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... ♦ Occultation of the white supergiant Eta (η) Leonis ♦ Lunar clair-obscur effects, including the Eyes of Clavius ♦ Jupiter shadow transits Red light friendly To preserve your night vision, this Sky Guide can be read…

The possibility of a naked-eye comet is an exciting prospect. In 2020 we had C/2020 F3 Neowise, which gave us a major comet boost. At the start of 2021, predictions that comet C/2021 A1 Leonard might perform a similar trick produced a lot of excitement. As time passed, A1 Leonard looked like it would fall short. Initially expected to be around the mag. +6.8 mark on 1 December, revised estimates now have it at around mag. +9.2. It won’t be the easiest of comets to locate either, appearing low in the morning sky. Following the latest brightness curve, A1 Leonard will only reach a peak magnitude of around mag. +6.8 on the 13th, which places it below naked-eye threshold and within binocular range. However, there’s still hope for cometary redemption…

Not all stars are constant in brightness, with many appearing to vary in output over time. Observing variable stars is a fulfilling and immensely important part of amateur astronomy, especially if you have the opportunity to do it regularly. Long-term observations reveal just how they change with time and give vital information about the nature of the variability. However, it’s not just stars that vary in brightness, as some nebulae do it too and we’ve picked three for you to track down and observe for this month’s ‘Sky Guide Challenge’. Variable nebulae are reflection nebulae which appear to change in brightness due to changes in the star that is illuminating them, or that star’s environment. There are three primary examples that are visible in the Northern Hemisphere: McNeil’s Nebula, Hind’s…

Before Boötes acquired his canine companions there was another mini-constellation in this area known as Cor Caroli, Charles’s Heart. The poet Edward Sherburne (1616-1702) wrote in his translation of The Sphere of Marcus Manilius that the name was “…in Memory of the most Glorious Prince and Martyr, Charles the First”, and that the King’s physician, Sir Charles Scarborough, had come up with the idea. According to historian Deborah Jean Warner, the name first appeared in print in 1673 on the northern half of a pair of celestial hemispheres by the cartographer Francis Lamb. He labelled the star Cor Caroli Regis Martyris (‘Heart of Charles the Martyred King’) – Charles I had declared himself “the martyr of the people” at his 1649 execution. On his chart, Lamb drew a heart and…

Like Lucy, Psyche is a NASA Discovery-class mission to learn more about asteroids. Psyche will focus on only one: a 220km-diameter chunk of mostly iron and nickel, discovered in 1852, and bearing the same name. 16 Psyche is one of the 10 most massive known asteroids, due to its metal content – the surface is around 90 per cent metal. Most planetary researchers believe that Psyche is the exposed metallic core of a protoplanet that lost its silicate mantle in a collision with another asteroid, probably billions of years ago. If they’re right, then the mission will offer a unique way to look at the interior of a Solar System body usually hidden inside a planet’s core. The launch of the Psyche spacecraft is scheduled for August 2022, on a…

1 ZWO OAG-L M68 off axis guider Price £191 • Supplier Widescreen Centre www.widescreen-centre.co.uk Off axis guiders (OAGs) help to ensure that your astrophotography setup remains on target and crisp. This OAG comes with a large 12mm x 12mm prism, giving a wider field of view and a more stable image. 2 Explore Scientific OIII 1.25-inch nebula filter Price £125 • Supplier Telescope House www.telescopehouse.com This filter helps to reduce the effects of artificial light and increase contrast on deep-sky objects by only letting in the specific wavelength of light given off by oxygen. Alternatively, it can be partnered up with other filters, like Sil (silicon) and Ha (hydrogenalpha), for multi-band astrophotography. 3 Ion8 food flask for hot food (large) Price £21.99 • Supplier Ion8 • www.ion8.co.uk A long night…

Enjoy bright Jupiter and Venus, and look out for two meteor showers, the Phoenicids and Puppid-Velids When to use this chart 1 Dec at 00:00 AEDT (13:00 UT) 15 Dec at 23:00 AEDT (12:00 UT) 30 Dec at 22:00 AEDT (11:00 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. DECEMBER HIGHLIGHTS Two meteor showers reach their peak this month. The Phoenicids is active from 28 November to 9 December. Although inconsistent over the years, with its radiant culminating in the early evening and close to new Moon, its peak night of the 2nd should provide many dark hours. The Puppid-Velids are visible in the…

Stuart Atkinson Astronomy writer “Many observers think of the Milky Way as a summer spectacle, but there are still plenty of sights to explore and enjoy in it during long midwinter nights.” Stuart guides us around our Galaxy’s top targets, page 28 Shaoni Bhattacharya Science Journalist “It was fascinating talking to Hannah Susorney and seeing how much we can learn about the internal workings of asteroids from looking at their shapes.” Shaoni meets an asteroid mapper, page 98 Ian Ridpath Astronomy populariser “Canes Venatici is small but rewarding to observe this month, yet how did it end up in the sky and who does its brightest star commemorate?” Ian investigates the mysteries of the constellation, page 62…

Seeing the misty, mottled arch of the Milky Way spanning the sky late on a clear summer night is one of the most enjoyable and memorable experiences for astronomers. It’s right up there with your first view of Saturn’s rings through a telescope and seeing a bright fireball skip and flare across the sky during a meteor shower. But why discuss the Milky Way at this time of year? Everyone knows that you can only see the Milky Way during the summer – that it’s a ‘summer sight’, right? Wrong. The Milky Way is still there on these frosty winter nights, it’s just not as dramatic or obvious. While the summer Milky Way is a naked-eye wonder, a broad trail of starry froth and foam that splits the sky in…

The Universe is littered with the most unlikely objects. In the depths of space lie dead stars, each containing more mass than the Sun but crammed into a space the size of a city. They are so tightly packed that a single teaspoon of their contents would weigh more than Mount Everest – or about as much as every human that has ever lived. What’s more, they spin multiple times a second, are highly magnetised and spit out rotating beams of radiation like celestial lighthouses. Astronomers call these enigmatic objects neutron stars. They form when a medium-sized star reaches the end of its life and explodes as a supernova, after which it leaves an incredibly dense core behind. Their name comes from the sub-atomic particles called neutrons, which you usually…

1 Wednesday With the Moon out of the way, this is a great time to enjoy our ‘Deep-sky tour’ on page 56. This month we’re looking at objects in northern Orion. 2 Thursday A gorgeous 5%-lit waning crescent Moon graces the morning sky, rising above the southeast horizon shortly before 05:30 UT, as seen from the centre of the UK. Waitjust over an hour and Mars will also appear, shining at mag. +1.6. 3 Friday Rounding off an excellent year of thin Moon spotting opportunities, after Mars rises this morning at around 06:20 UT, a 1%-lit Moon appears about 30 minutes later. Look for the pair low above the southeast horizon. 4 Saturday If you can grab a view of mag. –4.6 Venus this evening, the planet is currently showing…

KEY TO STAR CHARTS When to use this chart 1 December at 00:00 UT 15 December at 23:00 UT 31 December at 22:00 UT 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 December* Moonrise in December* Moonrise times 1 Dec 2021, 03:44 UT 5 Dec 2021, 09:53 UT 9 Dec 2021, 12:45 UT 13 Dec 2021, 13:36 UT 17 Dec 2021, 14:38…

Find out more about how we test equipment at www.skyatnightmagazine.com/scoring-categories PLUS: Books on the astronomer’s chair through history and living on the ISS, and a round-up of astronomy gear 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 How well does the Acuter Voyager MAK8O telescope live up to being an all-rounder? We put it to the test 87 SUBSCRIBE Discover the best new kit each month…

The Secret World of Stargazing Adrian West Hodder & Stoughton £14.99 • HB The Secret World of Stargazing will resonate with so many of us. Adrian West has produced a charming book with a strong emphasis on wellbeing: how and why stargazing is good for us, physically and mentally. Having lost a close friend last year, I spent a lot of time under the dark, clear sky whenever I could. It was a time for thinking, being alone and enjoying a connection with our natural world, the sky and sounds of nature. West focuses on these points in his book, and he does it in an uncomplicated way that we can all enjoy and empathise with. This is very much a book for anyone who is just starting out and…