Indholdsfortegnelse for December 2020 i BBC Sky at Night

Water, water everywhere across the lunar surface The Moon’s water could be protected from sunlight inside glass beads The Moon’s sunlit surfaces could have water locked away within them, a recently released study has shown. Traces of ice are known to hide in the permanently shadowed craters of the southern pole, but this novel find suggests water could be spread across more of the surface – a hopeful sign for future missions hoping to investigate water on the lunar surface. “Prior to the observations, we knew there was some kind of hydration,” says Casey Honniball, who led the study while doing her graduate thesis at the University of Hawaii. “But we didn’t know how much, if any, was actually water molecules like we drink every day, or something more like…

Looking back into Venus’s clouds Scientists are checking for evidence of phosphine from Pioneer mission data This September, a team of researchers led by Jane Greaves at Cardiff University published spectra collected by radio telescopes that indicated the presence of phosphine in the atmosphere of Venus. The debate this announcement subsequently triggered has been almost as heated as the Venusian climate… Experts have already published papers calling into question whether the gas is definitely there, as well as questioning what geological processes or atmospheric chemistry could have produced the gas, or whether it could feasibly be the signature of ultra-hardy Venusian life forms. I was particularly taken by the response from Rakesh Mogul at Cal Poly Pomona, California, and his colleagues, who have gone back to reanalyse 40 year-old data.…

The State of Astronomy This one-hour special looks back at the last decade and its many major advances and discoveries in astronomy. The team also look forward to the next 10 years and the challenges and opportunities ahead. Joining Chris and Maggie will be an ensemble of UK astronomers including Astronomer Royal, Lord Martin Rees, to answer questions sent in by viewers. BBC Four, 13 December, 10pm (first repeat BBC Four, 17 December, 7:30pm) Check www.bbc.co.uk/skyatnight for more up-to-date information…

“…things in heaven and earth…” Ahead of 21 December, Jane Green looks at literary conjunctions across the ages Will this month’s Great Conjunction of Jupiter and Saturn on the 21st improve your love life, or your career? Will there be thunderbolts and lightning and other very, very frightening things? Does its apparition herald a new messiah or monarch? War, flood, famine, plague and pestilence? Like astronomers - and astrologers - of centuries past, feel free to associate your own pattern of events to this super-close alignment. Celestial alignments have excited, inspired, ‘influenced’ and frightened humanity throughout history. This ‘conjunctionitis’, as I call it, has resulted in predictions and interpretations in literature too. Aristotle, in his work On the Causes of the Properties of the Elements, comforted readers by assuring them…

The Star of Bethlehem is a mystery still debated today among astronomers and scholars alike. Many theories for it have been put forward but none have been proven with any great confidence. However, one stands out as a good candidate - a planetary conjunction, or more precisely, a Great Conjunction. This was the cause put forward in 1603 by the great German astronomer and mathematician, Johannes Kepler, after he had observed a Great Conjunction himself. Today, we know of Kepler because of his groundbreaking work on the orbits of the planets and his three laws of planetary motion published in 1609 and 1619, but he was also an accomplished astrologer. It was this, coupled with his own Christian beliefs that led to his fascination with the true identity of the…

Huygens The European Space Agency’s Huygens probe was sent to Saturn’s moon Titan in 1997. It travelled on-board NASA’s Cassini spacecraft, and in 2005, after a parachute descent through haze-laden skies, landed on Titan, capturing never-before-seen views from its sub-zero surface. With Saturn’s average distance from Earth being 1.3 billion km, the pictures and scientific data Huygens sent home are still the furthest messages we’ve received from the terra firma of another world. Voyager 1 & 2 NASA’s two Voyager spacecraft performed spectacular tours of the outer planets in the 1970s and 1980s. The pictures Voyager 2 beamed back during flybys of distant Uranus and Neptune are the only close-up impressions we’ve had of these worlds and their intriguing array of moons. Both Voyager 1 and 2 have remained in…

Mercury Best time to see: 1 December, 30 minutes before sunrise Altitude: 2.5˚ (very low) Location: Libra Direction: Southeast Mercury is bright at around mag. -0.7 during the first week of December, but its apparent distance from the Sun is decreasing so it’s soon lost in the bright pre-sunrise sky. It reaches superior conjunction on the 20th and its late month reappearance into the evening twilight isn’t very favourable. Venus Best time to see: 1 December, 90 minutes before sunrise Altitude: 8˚ (low) Location: Libra Direction: Southeast Venus is a prominent, albeit low, planet in the dawn twilight this month. It rises 2 hours and 40 minutes before the Sun at the month’s start, shining at mag. -3.9 and showing an 88%-lit gibbous disc. By the month’s close, Venus rises…

Minor planet 13 Egeria reaches opposition this month, high in the sky in the constellation of Auriga, The Charioteer. Its brightness varies little throughout December, beginning the month at mag. +10.2, brightening to +10.0 by the 13th, before starting to dim again on the 27th. Egeria begins its track through Auriga 3.3˚ east of the mid-point of the line joining Menkalinan to Theta (θ) Aurigae. From here it tracks northwest to pass 2˚ south of Menkalinan on the night of 15/16 December, ending the month just over a degree south of the mid-point between Capella and Menkalinan. Named after a mythological nymph, Egeria was discovered by Annibale de Gasparis on 2 November 1850. It’s a main belt asteroid, orbiting between a perihelion distance of 2.36 AU and an aphelion distance…

The Moon is amazing to study and this month’s challenge is to reveal something interesting about the physicality of its orbit. Studying the Moon as a whole can reveal effects which may normally be overlooked. Its most obvious effect is the everchanging phase caused by the varying SunMoon-Earth angle. From thin waning and waxing crescents to the sky-obscuring glare of a full Moon, the phase-cycle is an integral part of our lives. The Moon’s orbit also gives us the daily tide cycle. But there’s another effect that may not be so obvious, which comes about because the distance between you and the Moon is not constant. The variation occurs in two ways. The first is connected with moonrise and moonset, when the Moon is physically slightly further from you than…

Make a lunar phase calculator Create an instrument to show the phase of the Moon on any given date This month’s project is a mechanical instrument that ‘calculates’ and displays the predicted phase of the Moon for any chosen day of the year. Our design uses a GT2 timing belt and pulleys – commonly used in printers and readily available online – to generate the movement, and we have provided downloadable plans and extra photos and diagrams, so the build should be straightforward. To use the calculator (pictured, above), you turn the year ring so that the wire pointer aligns with the date you are interested in. When you then look into the viewing tube you will see that the painted Moon ball has turned to reveal the predicted phase.…

Ced 214 Nebula Daniel Zoliro, Chouteau, Oklahoma, USA, 21-26 August 2020 Daniel says: “Ced 214 is a beautiful narrowband target that you don’t see imaged very often. With several clear nights in a row, I wanted this to be my longest integration project to date – 16 hours [imaging time] in total. I should have taken more OIII (Oxygen-III) data – it made combining the channels a little challenging – but I was able to make it work.” Equipment: ZWO ASI 1600MM Pro camera, Astro-Tech AT115EDT refractor, Sky-Watcher EQ6-R Pro mount Exposure: Ha 26x 300”, 77x 180”, OIII 106x 180”, SII 95x 180” Software: PixInsight, Photoshop, StarNet++ Daniel’s top tips: “I think that producing a great image comes down to three things: 1) good data – refine your capture skills…

How a school science club inspired the British Antarctic Survey to harness ESA’s Copernicus Sentinel-2 satellite to find new colonies of Emperor penguins How did you and your pupils at Stirling High School become involved in a satellite study of penguins? I was watching a David Attenborough programme where he was in Antarctica looking at various penguin colonies and he explained that they had been monitored using aerial photography. It got me thinking about whether it would be possible to monitor them from space, given the higher resolution of some of the new satellites. I came back to my small group of researchers, aged roughly 11 to 15, and we batted the idea around. We looked at satellite data from the European Space Agency’s Copernicus Sentinel-2, which gives us about…

Visit www.skyatnightmagazine.com/bonus-content/UTVK4QE/ to access this month’s selection of exclusive Bonus Content DECEMBER HIGHLIGHTS Interview: the biological Universe We speak to biologist Wallace Arthur about why he believes life could be thriving throughout the Universe. The Sky at Night: Beyond the Visible The team visit Jodrell Bank to find out more about astronomy that goes beyond what can be seen with the human eye. Audiobook preview: Tim Peake’s Limitless Download and listen to two chapters from the British astronaut’s brand new autobiography, narrated by Tim himself. The Virtual Planetarium Pete Lawrence and Paul Abel guide us through the best sights to see in the night sky this month.…

Back in September 2020, scientists revealed that they had found phosphine in Venus’s atmosphere. On Earth, phosphine is only produced by life - either by humans in a laboratory or by anaerobic organisms - so could there be a habitable zone in Venus’s cloud deck, home to a phosphine-producing type of hardy life form? Even as an optimistic astrobiologist, I feel this is an unlikely scenario; I expect that with further research we will discover that the phosphine is being produced by a weird, currently unexplained, geochemical or atmospheric process. There’s also the possibility that the result could be an error in processing of the data - responsible scientists have to acknowledge that. Yet despite the current firestorm of speculation about the origin of this signal, it has reignited and…

Outdoor film experience OM Dark Sky Park and Observatory, Omagh, until March Wrap up warm for a journey through space and time via a film projected onto the outside of Northern Ireland’s brand new OM Dark Sky Park and Observatory. Guided tours of the new attraction are also available. The events run every day until March and you can book tickets at bit.ly/omdarksky Cambrian Mountains stargazing weekend Staylittle, mid Wales, 11-13 December Stay in a deluxe cabin and enjoy two days of astronomy tuition, observation and astrophotography under some very dark skies. The weekend costs from £374.35 per cabin (up to four people). Book at bit.ly/darkskywalestraining Night ‘awe-walk’ Urra Moor, North Yorkshire, 13 and 14 December 2020, 4pm Join a small, socially distanced group for a guided walk around the…

The winter solstice on 21 December is the beginning of astronomical winter for the Northern Hemisphere, and many like to witness or capture the rising and setting of the Sun on this, the shortest day. Astronomers have been anticipating this year’s winter solstice (quite literally) for decades, not because of the solstice itself, but because of the planetary show that will be visible just after the Sun has gone down - to some it may be the greatest astronomical event they witness in their lifetimes. On 21 December this year the two behemoths of our Solar System - Jupiter and Saturn - will be coming together in what astronomers call a ‘Great Conjunction’, appearing to the naked eye for many as a single bright ‘star’. Indeed, this year’s event is…

There’s a good chance that as you read these words, almost seven lighthours from Earth an explorer is opening its eyes to the tenebrous emptiness of deep space. That explorer is the New Horizons spacecraft, currently sailing through the outer Solar System at 50,000km/h. This December it will spend several days turning one of its cameras towards some of the small, icy bodies that live in the deep recesses of this isolated realm. While the pictures returned by this new set of observations will be little more than dots against a starry backdrop, they could help researchers plumb the deep history of our planetary neighbourhood. When it launched in 2006, New Horizons’ primary target was the Pluto system. The one-time planet and its moons lie some 5.75 billion km from…

DON’T MISS GEMINIDS 2020 BEST TIME TO SEE: Activity between 4–17 December, peak night 13/14 December Which is the best meteor shower of the year? Most would probably say the August Perseids; with a peak zenithal hourly rate (ZHR) of 110 meteors per hour and occurring under the relatively balmy conditions of summer, what’s not to like? However, this month’s Geminid shower outstrips the Perseids in a number of ways. This may sound like a controversial statement but to explain it we need to look more closely at the often-misused value that is the zenithal hourly rate. A shower’s ZHR is a normalised value, a figure which compensates for all the issues that degrade a shower’s visual performance. The ZHR considers how much of the sky you can, or cannot…

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 2020, 16:37 UT 5 Dec 2020, 20:38 UT 9 Dec 2020, 00:43 UT 13 Dec 2020, 06:36 UT 17 Dec 2020, 11:09…

Elnath (Beta (β) Tauri) is the second brightest star in the constellation of Taurus, the Bull, and represents the northern horn tip of the creature. On star charts it is an oddity, commonly shown with connecting lines not just to Taurus, but also to Auriga, which lies further north. Other such switchovers are also present in the night sky, but these are often due to the formalisation of constellation boundaries from 1930. In the case of Elnath, a name which means ‘the butting’, the star was allocated to both constellations by Ptolemy and Johann Bayer, who labelled it as both Beta (β) Tauri and Gamma (a) Aurigae, a star with two identities! The latter name was dropped in 1930 during the process of boundary formalisation. An interesting fact related to…

1 NGC 188 NGC 188 is an open cluster near the North Celestial Pole (NCP). Its declination is 85.3˚ and it sits 4˚ south of Polaris. In Patrick Moore’s Caldwell Catalogue - a list of bright deep-sky objects organised by declination - it’s listed as Caldwell 1. The best way to visualise NGC 188’s location is to imagine it in a squat isosceles triangle, Polaris at the top, mag. +4.3 Delta (δ) Ursae Minoris at one base vertex and NGC 188 at the other in the direction of Cassiopeia. It has an apparent diameter of 0.25˚ and shines at eighth magnitude. It suits a low power eyepiece. ◻ SEEN IT 2 NGC 2276 If your scope is on an equatorial mount, our first two targets may be tricky; the irony…

With enormous modern telescopes and sensitive detectors, professional astronomers can see far beyond what most back garden telescopes are capable of. As far as our own Solar System is concerned, one of the farthest objects observed so far is a 500km-wide asteroid, 2018VG18. Also known as Farout, it is over 120 times further from the Sun than Earth, or three times further away than dwarf planet Pluto. If you were standing on Farout’s dark, pink icy surface, Earth would be a mag. +6.8 ‘star’ hugging close to the Sun and Jupiter would shine at barely mag. +5.0. If a space probe ever reaches Farout it will take 17 hours for its radio signals and images to reach Earth. As for the most distant object ever seen in the Universe, the…

Photograph the Great Conjunction Capture Saturn and Jupiter in one image thanks to a unique event that hasn’t occured since 1623 Saturn and Jupiter reach their Great Conjunction on 21 December, when both planets will appear separated by just 6 arcminutes, the closest they’ve appeared together since July 1623. If the weather plays ball, this event will offer a chance to catch both planets as discs in a single image. A bit of planning will pay off however, because even though 6 arcminutes is fairly easy to catch using a planetary camera, it’s best to image in such a way that the 6-arcminute separation fits optimally inside the camera’s imaging frame, meaning the apparent size of each planet will be maximised for the view. Achieving the correct imaging scale is…

HUBBLE SPACE TELESCOPE, 23 OCTOBER 2020 Flying together at huge speeds, locked into a relationship that may eventually see them merge, these galaxies captured by the Hubble Space Telescope are NGC 2799 (left) and NGC 2798 (right), in the constellation of Lynx. Already the left galaxy is distorting under the other’s influence, its stars appearing to peel away and fall into the centre of NGC 2798’s spiral. But don’t hold your breath for a calamitous head-on collision – the process will last millions of years, perhaps even a billion. What’s more, although galactic collisions may suggest chaos and destruction, the distances between each galaxy’s components are so immense that they are more likely to pass through each other with little connection. Our own Milky Way is also on course for…

InSight out of sight After months of trying, NASA’s InSight Mars lander finally got the head of its heat probe fully into the Martian surface – with a helping hand from the lander’s robotic arm. The probe was meant to burrow itself into the soil, dragging a string of heat sensors behind it, but struggled to gain purchase in the loose soil. Earth’s gold problem Earth has too much gold. The element is normally created in the hearts of large stars, but there aren’t enough nearby to explain Earth’s rich veins of gold. A new study found even exotic gold creation methods involving neutron stars and black holes couldn’t make up for the shortfall, begging the question: where does all this gold come from? Baby star, baby planet An infant…

Adapting to these challenging times, the Society for Popular Astronomy (SPA) has embraced the virtual life with a host of interactive PopAstro Live videos. Hosted by Vicky Duncalf and featuring a variety of guests, recent topics include: diversity in astronomy with Heidi Thiemann from the Open University and Lucy Williams from the RAS; the science of space suits with Dallas Campbell and Stephen Wisdom; Alice Sheppard talking about citizen science projects; a radio astronomy special with Dr Anna Bonaldi; and a life on Venus special with Dave Eagle, Nigel Henbest and Dr Chris North. For newsletters, magazines and support, you can join the SPA from £23 a year. To find their videos, search ‘Society for Popular Astronomy’ on Facebook and visit youtube.com/c/popastro/videos…

The year 2020 will be one that many of us will be forgiven for wanting to forget but in astronomical terms it will end in a blaze of glory, with one of the rarest and most unmissable sights in the heavens, a ‘Great Conjunction’. Great Conjunctions are once-in-a- generation events that occur on average every 19.6 years, and involve the visually close pairing of the two giants of the Solar System, Jupiter and Saturn. This phenomenon, of course, is just a line of sight effect as viewed from Earth, but it is nonetheless a spectacular sight. These conjunctions happen so rarely because of the leisurely journey both Jupiter and Saturn take as they orbit the Sun, with Jupiter taking 11.86 years and Saturn taking 29.5 years respectively. Each Earth year,…

The New Horizons spacecraft is currently far beyond the orbit of Pluto and indeed already well past the orbit of the Kuiper Belt object Arrokoth, which it visited in late 2018 and early 2019. By the middle of this month it will be some 7.4 billion km from Earth. You can keep track of New Horizons and the four other spacecraft speeding away from our Solar System yourself using the NASA Eyes app at https://eyes.nasa.gov/…

Mercury Best time to see: 1 December, 30 minutes before sunrise Altitude: 2.5˚ (very low) Location: Libra Direction: Southeast Mercury is bright at around mag. -0.7 during the first week of December, but its apparent distance from the Sun is decreasing so it’s soon lost in the bright pre-sunrise sky. It reaches superior conjunction on the 20th and its late month reappearance into the evening twilight isn’t very favourable. Venus Best time to see: 1 December, 90 minutes before sunrise Altitude: 8˚ (low) Location: Libra Direction: Southeast Venus is a prominent, albeit low, planet in the dawn twilight this month. It rises 2 hours and 40 minutes before the Sun at the month’s start, shining at mag. -3.9 and showing an 88%-lit gibbous disc. By the month’s close, Venus rises…

Unlike its neighbouring seas which frame it well, Mare Vaporum or the Sea of Vapors lacks a well-defined boundary. In this it is unlike Mare Imbrium to the northwest, Serenitatis to the northeast and Tranquillitatis to the east; instead 270km x 400km Vaporum appears as an irregular dark patch. A dark volcanic region known as Pyroclastic ‘Mare Vaporum’ dominates the southeast corner. To the south is the wonderful form of the Rima Hyginus, a curious collection of 1-4km craterlets and rilles that form two lines at an angle to one another, either side of 10km Hyginus. The appearance of the crater lines and Hyginus is reminiscent of a large bird flying directly towards you. The multitude of small craterlets and the rille, or narrow channel, that connects them is also…

1. Perseus Double Cluster The Double Cluster is nice and high in December evenings, so you’ll probably be able to see it with your naked eye, about one-third of the way from Miram (Eta (η) Persei) to Ruchbah (Delta (δ) Cassiopeiae). 10x50 binoculars transform a single fuzzy patch into an elongated glow with two cores of brightness. Some multicoloured chains of stars lead away from the Double Cluster; it’s worth following them to see where they lead. ☐ SEEN IT 2. M103 Get Ruchbah in the middle of your field of view and about 1° to the east you’ll see a small (6 arcminute across) triangular glow that stands out from the Milky Way. Although it has a Messier number, M103 is one of more than 20 objects in Messier’s…

M31 is famously the most distant thing visible to the naked eye, but that’s only true if you have good eyesight, a dark sky with no light pollution and you know where to look for it. Luckily, even if you have none of those things it’s quite easy to photograph this beautiful spiral galaxy – all you need is a DSLR on a sturdy tripod. You don’t even need a tracker or stacking software. To take a portrait of the Andromeda Galaxy, M31, fit either your wide-angle lens or standard 50mm lens onto your DSLR, mount it on a sturdy tripod, open the lens to its widest aperture and then focus in sharply on a light on the horizon. With its ISO set to 800, aim your camera at the…

How to stack DSLR images of the Moon Create a crisper lunar image by stacking in AutoStakkert! and removing unwanted noise The biggest enemy of the astrophotographer is noise, the unwanted artefacts that appear in images. We often hear about how deep-sky images can be stacked to improve the signal-to-noise ratio (SNR) - where the ‘signal’ represents the real features in an image we want to keep - but it can also be a problem when we are imaging our nearest neighbour, the Moon. With a DSLR, noise will still be present even at lower ISO settings and this can spoil the appearance of a lunar image (see example images, right). Fortunately, there are ways to reduce the amount of noise present so that the image looks cleaner and sharper.…

1 Helios 2x40 Star Field Binoculars Price £89 • Supplier Tring Astronomy Centre Tel 01442 822997 • www.tringastro.co.uk With a wide field of view and low magnification, these binoculars give you the same viewing experience as using the naked eye but with super-enhanced vision. Ideal for taking a deeper look at wide-field objects, such as constellations of the Milky Way. 2 Pegasus FlatMaster 150 flat field illuminator Price £169 • Supplier William Optics Tel 01353 776199 • www.widescreen-centre.co.uk ADVANCED Flat field panels provide a uniform illumination source to ensure you have the highest quality flat field frames for processing your images. This model has an adjustable brightness, allowing you to fine tune to best suit your setup. 3 Milky way mug Price £8.99 • Supplier Society for Popular Astronomy •…