Innholdsfortegnelse for Sky Yearbook 2018 i BBC Sky at Night

“The deeper you’re able to look, the greater the insight into these many and varied objects you’ll get” Space is many things: cold, dark, inhospitable, unimaginably vast and almost a perfect vacuum. But it’s not empty. Stare up at the sky after the Sun has gone down and the dark canvas that surrounds us is perforated by countless pinpricks of light. These tiny specks are the planets, stars, nebulae, comets, constellations and galaxies that occupy the nothingness and light the night sky up with fascination. The sight of these objects hanging in the sky is impressive enough when seen with just your eyes. But bring a pair of binoculars or a telescope into the equation and you open a window onto another world filled with marvels and curiosities. And the…

SkySafari 5 Pro Price: £38.99 Platform: iOS/Android Pros: Remote control of Go-To telescopes; extensive data; custom observing lists; red-light mode Cons: Expensive; a huge app at 1.7GB; requires telescope accessories No app goes as deep as SkySafari 5 Pro. On its own it’s a great astronomy app: you can create observing lists, check celestial coordinates, get ISS/Iridium satellite notifications, view images from the Digitized Sky Survey and even explore an intergalactic map of where an observing target is in the Universe relative to the Sun. However, this app is both expensive and huge in terms of file size. Using it to remotely control a computerised Go-To telescope requires a separate adaptor to let the app communicate with the setup, which can cost several hundred pounds. http://skysafariastronomy.com Universe2go Price: Free Platform:…

Over the past 20 years digital video imaging has developed to become the leading way of recording planetary detail. The method uses a high frame rate planetary camera to capture a stream of hundreds or thousands of digital frames. The best of them are then aligned and stacked to produce a single master frame in which most of the blurring effects of our atmosphere have been averaged out. This stack is then sharpened with dedicated software to draw out surface detail and produce wonderful planetary images. To make the most of this technique, each exposure needs to be brief enough that it isn’t too blurred by the constant agitation of the atmosphere. Yet the short exposure times combined with the low surface brightness of most planets means that each frame…

The Schulman Telescope is hosted by the University of Arizona in the US and is located on nearby Mount Lemmon at an elevation of 2,800m. The location provides you with a dark sky, good seeing and good weather. Between September and June, 70 per cent of the nights should be clear, something you can check via its website. The telescope has an aperture of 31.5-inch and a remarkable focal length of almost 6m. As with iTelescope and LightBuckets, you are given full control over the telescope, allowing you to adjust all of the parameters yourself. Although the interface for controlling the telescope is quite detailed, booking observing time is cumbersome, as no web portal exists for this purpose. Booking enquires have to be made via email or telephone and there…

While infrared astronomy has allowed us to peer into hidden realms within the Milky Way, it can also reveal the secrets of the countless galaxies that lie far beyond the limits of our own great, stellar metropolis. Some appear as little more than faint smudges of light to even the most powerful space telescopes, yet can be studied to understand the distant (and therefore early) Universe. Others, such as our cosmic neighbour the Andromeda Galaxy, M31, are much nearer – and, typically, bigger on the sky – and so offer us a chance to examine the detailed workings of another galaxy ‘up close’. Like the Milky Way, M31 is a spiral galaxy. But that’s not the only similarity the two share. In the visible light image above left, dark dust…

Glimpse Jupiter through a telescope and you should be able to catch sight of the intricate pattern of atmospheric belts and zones the planet is so well known for. We see Jupiter’s cloud tops in visible light because they are illuminated by the Sun. But the planet also glows in the infrared, due to the heat deep within its massive, gaseous bulk. “We believe it is the primordial heat left over from when Jupiter formed,” explains Leigh Fletcher of the University of Leicester, who used ESO’s Very Large Telescope to capture the infrared image of the planet below. Such infrared studies are useful for examining the various parts of Jupiter’s atmosphere, says Fletcher. “The various gases that are present within an atmosphere will absorb light at different wavelengths. They have…

With the arrival of spring, the night sky takes on a far more subtle appearance. This is due to the Milky Way rotating out of view so we’re now looking out at right-angles to our Galactic plane into deep space. For this reason, we lose many of our Galaxy’s local deep-sky objects; these are replaced by the less bright but equally impressive galaxies that lie beyond the Milky Way. The constellation of Leo, the Lion, takes centre stage, easily identified thanks to its distinctive Sickle asterism, which marks the lion’s head and foreleg. Close to Leo’s forward-pointing rear leg is the M96 group of galaxies. These are visible through a small telescope as faint, mostly elliptical smudges. A far more impressive group lies close to Leo’s rear or eastern back…

The recent Northern Hemisphere spring equinox on 20 March and the onset of British Summer Time on 25 March, mean getting a good view of the night sky is harder than it was during the previous months. Not all astronomy relies on the night sky, though, and for those who love to observe the Sun through a certified solar safety filter, April sees our nearest star climbing to a decent height above the horizon and out of the turbulent air found at lower altitudes. During the nights in April, the Plough is located virtually overhead and can be used to find other stars and constellations. Imagine the pattern as a saucepan and extend the side nearest the handle southwest. Keep going approximately 10 times that distance to arrive at Regulus,…

INSIGHT ASTRONOMY PHOTOGRAPHER OF THE YEAR WINNER YOUNG ASTRONOMY PHOTOGRAPHER OF THE YEAR Saturn Olivia Williamson (UK – aged 13) Key dates ALL MONTH July is an ideal month to watch for noctilucent cloud displays 6 JULY Earth is at aphelion, farthest from the Sun at 152,096,156km (94,508,170 miles) 27 JULY The full Moon rises totally eclipsed by the Earth’s shadow 27 JULY Mars reaches opposition 28 JULY Peak of the Delta Aquariid meteor shower under Moonlight interference…

After the bright, twilight nights of early July, the latter part of that month re-introduces the UK to true darkness once again. Unfortunately, this period in 2018 is compromised by a bright Moon. But there is a positive side to this as the full Moon, which occurs on 26 July, means the sky is good and dark from the second week of August, offering perhaps the best opportunity to view the summer Milky Way from the UK. August also sees the annual Perseid meteor shower. This is one of the more reliable showers, reaching peak activity on the night of 12/13 August. In 2018 this peak activity will coincide with moonless conditions and, if the skies are clear, it will be a spectacle worth watching out for. Under dark-sky conditions,…

“In photographs, the Pillars of Creation form a second, smaller eagle, seen in profile and clutching a fish in its talons” Stats NAME AND CATALOGUE REFERENCE: Eagle Nebula, Messier 16 CONSTELLATION: Serpens Cauda OBJECT TYPE: Open cluster with nebulosity VISUAL BRIGHTNESS: Mag. +6.4 (binocular) DISTANCE: 7,000 lightyears APPARENT SIZE: 7 arcminutes PHYSICAL SIZE: Cluster diameter 15 lightyears, nebula extends out to 75x55 lightyears BEST TIME TO SEE: 15 Jul 00:00 BST, 15 Aug 22:00 BST, 15 Sep 20:30 BST BINOCULARS Getting a closer look M16 is a famous object known as the Eagle Nebula and home of the ‘Pillars of Creation’, one of Hubble’s most iconic photographs. M16 is located approximately 2.5° west and slightly north of mag. +4.7 Gamma (γ) Scuti, in a region of sky that looks ‘fuzzy’…

This month the Sun reaches its most southerly position in the sky – the December solstice. This is a good thing too, as Orion, the Hunter, is well placed this month. His seven main stars stride across the December night sky like an old friend. The constellation contains many deepsky riches, the most obvious of which sits in the centre of Orion’s sword, a pattern that appears to hang down from his belt. Any optical instrument, from small binoculars to the largest of telescopes, will confirm that this is the wonderful Orion Nebula, M42. The nebula is a cloud of glowing gas and its brightest region, when seen through a small telescope, has a distinct kidney shape. At the heart of the nebula sits a small open cluster formed from…

STARS & NEBULAE NGC 281 Pacman Andriy Borovkov, Ukraine Equipment: Moravian Instruments G2-8300 mono CCD camera, TS-Optics UNC 12-inch New tonian reflector, Sky-Watcher EQ8 Pro equatorial mount. YOUNG ASTRONOMY PHOTOGRAPHER OF THE YEAR 1. Milky Way above Alpe di Siusi/Dolomites Fabian Dalpiaz, Italy – aged 15 Equipment: Canon EOS 5D Mark III DSLR camera, 50mm. 2. Rosa Mountain Andrea Imazio, Italy – aged 8 Equipment: Nikon D5500 DSLR camera, 18mm lens. 3. Orion’s Gaseous Nebula Sebastien Grech, UK – aged 13 Equipment: Canon EOS 60D DSLR camera, Sky-Watcher 150 reflector, Sky-Watcher EQ3 Pro mount. OUR SUN Ghostly Sun Michael Wilkinson, UK Equipment: ZWO ASI178MM CMOS camera, APM 3-inch refractor, Vixen Great Polaris mount. PLANETS, COMETS & ASTEROIDS Near Earth Object 164121 (2003 YT1) Derek Robson, UK Equipment: Canon EOS 1100D…

Astronomy is unique among the sciences in that everyday people can contribute to the record. There are several professional organisations that accept amateur astronomers’ images, as well as their sketches and reports of visual observations, and make them available for professional astronomers to use for research. On this page is a list of the main professional astronomical bodies that will accept your data, depending on what it relates to. Before submitting your images or observations, however, it’s worth reading and applying the general pointers regarding the preferred format for the data (below), so that professional astronomers can extract the most information from it. It’s also worth checking each organisation’s website (bottom) for more specific guidance on how and what you can submit. Make your images count for science To give…

Your smartphone can be a powerful accessory during an observing session. By combining GPS positioning and an accelerometer, your phone can tell not only where you are on the planet, but exactly where you’re pointing it; cue planetarium apps that show you exactly what you’re looking at in the night sky. There are apps to help you plan observing sessions, find satellites and the International Space Station. There are apps that aid astrophotography, and provide the latest astronomical updates. Over the page, we look at 15 of these essential tools for astronomy. ABOUT THE WRITER Eclipse-chaser and dark skies expert Jamie Carter is the author of A Stargazing Program for Beginners: A Pocket Field Guide.…

Adobe Photoshop Express Price: Free Platform: iOS/Android/ Windows Phone Pros: Effective noise reduction Cons: Fewer options than desktop version If you’re doing astrophotography or creating nightscapes using a camera with Wi-Fi, this app version of Photoshop makes a good stand-in for the desktop software so popular with astro imagers, letting you edit and check photos on the go. Key features include sharpen, clarity and exposure sliders, but most useful is a clever noise-reduction feature that automatically zooms-in on the image. It also includes shortcuts to upload finished images to everything from Adobe’s Creative Cloud to social media. www.adobe.com PhotoPills Price: £9.99 Platform: iOS/Android Pros: Precise positioning for Sun; Moon and Milky Way Cons: Complex interface takes some getting used to Want to capture that iconic moonrise or moonset photo where…

We’re all pretty familiar with what noise looks like, but what actually causes it? Well, noise in images is the unwanted variation in pixel to pixel brightness, which interferes with the true brightness variation of the object in an image. For planetary imaging there are only two sources of pixel noise that generally matter: read noise and shot noise. Read noise is electrical circuit noise that’s added to the image signal from each pixel when it is read from the sensor chip. It is generally not an issue for planetary imaging, unless you’re using narrow bandpass filters or the object isn’t very bright – the latter applies to Uranus and Neptune. In these cases read noise can start to become a nuisance, especially if the camera suffers from it occurring…

Currently used by more than 10,000 astronomers, iTelescope is probably the most developed service on the list. Signing up gets you access to a number of different reflectors and refractors, ranging from 3.5 inches to 27.5 inches in aperture and with varying focal lengths. Its sites are in the US, Spain and Australia, allowing you to enjoy the wonders of both northern and southern skies. All are situated in areas with little light pollution and good seeing conditions, and 70 per cent of nights are clear. Though iTelescope is described as being ready for beginners and offers many tutorials, a basic knowledge of telescopes and astrophotography is helpful since the system allows you to alter almost all imaginable parameters yourself. The costs for the service are reasonable as you are…

Step outside on a summer’s evening and, if you’re away from light pollution, you may be able to spot the bright central region of our Milky Way rising up over the southern horizon. If you allow your eyes to adapt to the darkness you should see that within the band of the Galaxy there are numerous dark lanes and tendrils where the glow is absent, and it looks like there aren’t any stars there. These are actually dust-rich nebulae within our Galaxy’s spiral arms that are obscuring the light from the stars beyond them. The dust grains within these clouds are good at absorbing the visible light that our eyes detect, so they appear silhouetted. The longer wavelengths of infrared light, however, are able to pass through these grains without…

Mighty Orion, the Hunter, is still prominent in February’s sky but his time is limited. The Northern Hemisphere’s spring equinox occurs on 20 March marking the time of year when the length of night is shortening at its most rapid rate. Consequently, enjoy Orion during February before he makes his rapid stage exit to the west. The winter Milky Way flows down the sky to the east of Orion and as it does so it clips the feet of Gemini, the Twins. The two principal stars of Gemini, Castor and Pollux, are easily located by extending a line from Rigel through Betelgeuse, both in Orion, for 1.5x that distance again. Castor and Pollux are easy to identify because they are bright and look similar, at least on first appearance. Look…

“M41 may have been reported by Aristotle as a faint, naked-eye object as far back as 325 BC” Stats NAME AND CATALOGUE REFERENCE: Messier 41 CONSTELLATION: Canis Major OBJECT TYPE: Open cluster VISUAL BRIGHTNESS: Mag. +4.5 (naked eye) APPARENT SIZE: 38 arcminutes DISTANCE: 2,300 lightyears PHYSICAL SIZE: 26 lightyears across BEST TIME TO SEE: 1 Jan 00:00 UT, 1 Feb 22:00 UT, 1 Mar 20:00 UT NAKED EYE The view from the ground Messier 41 is an open cluster located within Canis Major, the Great Dog. It’s in a fairly low part of the sky where it reaches an altitude about 16° up as seen from the centre of the UK. This might be why it tends to get overlooked as a naked-eye object. Despite being mag. +4.5, its brightness…

The Northern Hemisphere’s summer solstice occurs on 21 June, when at 10:07 UT the Sun reaches its most northerly position in the sky. Consequently, our star never sinks that far beneath the northern horizon at night and it never becomes really dark. The earliest sunrise for the year occurs on 17 June, while the latest sunset on 25 June. There’s still plenty to see though. June and July are regarded as the best months to see the rare phenomenon known as noctilucent clouds, or NLCs. Although these are atmospheric, their origins are linked to space. They are the highest clouds on Earth consisting of tiny ice crystals forming predominantly around the particles left behind when meteoroids vaporise in the atmosphere as meteors. NLC season runs from late May through to…

The Northern Hemisphere’s summer solstice occurs on 21 June and from much of the UK the start of July can be a frustrating time for astronomy. The days and weeks around the solstice produce night-time skies that never get truly dark, a problem that gets worse the further north you are. But, towards the end of the month a short period of true darkness does return for many. Rather frustratingly in 2018, the return of dark skies during late July will be marred by the presence of a bright Moon. However, the full Moon that occurs on 27 July will rise fully eclipsed as seen from the UK, the first totally eclipsed Moon seen since 28 September 2015. The summer sky is dominated by a large asterism known as the…

INSIGHT ASTRONOMY PHOTOGRAPHER OF THE YEAR WINNER SIR PATRICK MOORE PRIZE FOR BEST NEWCOMER The Cone Nebula (NGC 2264) Jason Green (Gibraltar) Key dates 4 OCTOBER This morning’s 29% waning crescent Moon is 3.3° from the Beehive Cluster, M44 9 OCTOBER Peak of the Draconid meteor shower 10 OCTOBER Peak of the Southern Taurid meteor shower under favourable conditions 21 OCTOBER Peak of the Orionid meteor shower under unfavourable Moon conditions 24 OCTOBER Uranus at opposition…

Early evening sees the stars of autumn fill the sky in the south and this is a great time to see the Andromeda Galaxy, M31. The core of this galaxy can be seen as an elongated smudge to the north of the middle of the wedge-shaped constellation of Andromeda, the Chained Princess. South of Andromeda lays small but distinct Triangulum, the Triangle. This constellation resembles a narrow isosceles triangle and in mythology was supposed to represent the shape of the island of Sicily. Located west and slightly north of the triangle’s apex is the Triangulum Galaxy, M33. It’s a tricky object to see through a telescope because it appears face on to us, a bit like a Catherine wheel. Consequently it has low surface brightness. Clusters and comets South of…

“The pointed tip of the V, marked by Gamma Tauri, represents the bull’s nose” Stats NAME AND CATALOGUE REFERENCE: Hyades, Melotte 25 CONSTELLATION: Taurus OBJECT TYPE: Open cluster VISUAL BRIGHTNESS: Mag. +0.5 (naked eye) DISTANCE: 153 lightyears APPARENT SIZE: 330 arcminutes PHYSICAL SIZE: Central core diameter 8.8 lightyears, outer envelope diameter 33 lightyears BEST TIME TO SEE: 15 Oct 03:00 UT, 15 Nov 01:00 UT, 15 Dec 23:00 UT NAKED EYE The view from the ground The Hyades is the V-shaped open cluster representing the face of Taurus. The cluster is bright, large and easy to find. Simply extend the line of Orion’s belt northwest to arrive at the orange star Aldebaran (Alpha (α) Tauri). This sits at the end of the southern arm of the V-shape. The rest of…

The Hertzsrpung-Russell Diagram (HRD) is a fundamental way to show the relationship between a star’s absolute magnitude, or luminosity, and its temperature. The plot is very important in astronomy and astrophysics as it helps us understand how stars evolve over time. You can produce your own HRD in a very straightforward manner by using graph paper with axes representing surface temperature and absolute magnitude. All you need to do to populate the graph is to access one of the multitudes of catalogues available online or via planetarium programs, extract the information for a particular star and plot it in the correct position. With 21st-century technology and the vast amount of star data available, a more efficient method would probably be to write some computer software to automate this process. However,…

STEP 1 Use a craft knife and a metal rule to cut some strips of thin flexible plastic approximately 12-15mm wide to make bands for the inside of your finder’s dew shield and around 20mm wide for the outside. We used red plastic to show up in the photos. STEP 2 Test fit the inner band inside the finder’s dew shield and mark where it overlaps. Space the LEDs along it equally and use a hot-melt glue gun to stick them in place. Make sure the LEDs are all orientated the same way – the long leg is positive. STEP 3 Insert the first band and glue the overlapping join. Make a wider band to fit around the outside of the finder. Fold the positive legs of the LEDs over…

STEP 1 Attach the dome template downloaded from http://bit.ly/2z71hyu to the lid of the junction box. Drill a 2mm pilot hole through the centre mark. Place the dome accurately on top of the dome template and drill six 4mm holes through the dome’s flange and the box’s lid. STEP 2 Remove the dome, then drill the seven 4mm holes for the heater element stand-off bolts and the wire exit point. Using the centre 2mm pilot hole drilled in Step 1 as a guide, use a 2-inch hole-cutter to cut out the hole for the lens. STEP 3 Cut a 130cm length of nichrome wire and thread it through the 1.6mm heat-shrink tube and shrink it using a hair dryer or heat gun. Cut three 6cm lengths of 5mm-diameter heat-shrink tubing…

Stellarium Mobile Sky Map Price: £2.99/£2.19/£1.49 Platform: iOS/Android/Windows Phone Pros: Realistic views; red-light mode; light-pollution slider Cons: Mostly technical data on stars This planetarium app from the creators of the original and free Stellarium computer software impresses by keeping it real. As well as a virtual horizon, it has an option to mimic what you can see with the naked eye, and even a light-pollution adjuster. Overlays of the constellation lines, and equatorial and azimuthal grids can be superimposed. There’s also an easy-to-reach red-light mode and an unexpected section on the star lore of other cultures, including Inuit, Navajo and Aztec. https://noctua-software.com GoSkyWatch Planetarium Price: £3.99 Platform: iOS Pros: Target-search; celestial grid design; red-light mode Cons: Bright stars only; obvious and invisible planets are treated the same This app for…

Cosmic Watch Price: £4.99/£3.35 Platform: iOS/Android Pros: Creative design; encourages a new perspective on stargazing Cons: Large app at 178MB Time is not a number, it’s a precise position in space, as you’ll quickly learn from this stunning 3D app that’s both a standard world clock and an astronomical timepiece. You look onto Earth from above your actual GPS location, and see which stars and constellations are overhead. Meanwhile, the changing positions of the Sun, the Moon, the planets on their orbits and even the shifting position of the Milky Way beyond are all integrated to create an app packed with detail. http://cosmic-watch.com NASA Price: Free Platform: iOS/Android/Kindle Fire Pros: Live rocket launches on NASA TV; latest images from NASA missions Cons: NASA’s Astronomy Picture of the Day images are…

By stacking your frames you’ll reduce random noise, but this reduction depends on the size of the stack. By recording for longer you can reduce the noise in the stack. In fact, shot noise reduces by the square root of the number of frames in the stack. Thus an imaging run that gathers four times as many frames will give a stacked image with half the amount of noise. The square-root relationship between shot noise and both the number of photons gathered and the number of frames in the stack gives rise to a key principle of great importance in planetary imaging: the amount of shot noise in the stacked image is solely dependent on the accumulated exposure time, regardless of the noise in the individual frames. You can choose…

Cast your eyes over the finest visible light images of the Orion Nebula – the really deep, long-exposure shots captured by the world’s best astrophotographers – and there’s one thing that always stands out: the dark clouds of dust and gas that surround the nebula. These brownish-red swirls in fact extend over great swathes of Orion. Infrared views, like the one shown below, reveal that, far from being just bland cosmic murk, many conceal the nascent glow of baby stars.…

KEY TO STAR CHARTS January at a glance The long, cold nights of January provide an immersive stargazing experience but remember to wrap up warm. The most obvious constellation on view is Orion, the Hunter. Formed from seven bright stars, this is one pattern most people can recognise. Three bright stars in a line form the hunter’s belt and hanging below is Orion’s sword containing the Orion Nebula, a glowing gas cloud easily seen with binoculars or a small telescope. Follow the line of Orion’s belt southeast to arrive at Sirius, the brightest night-time star of them all. From the UK, Sirius only ever manages to reach an altitude of around 20° so its light has to pass through a thick, often turbulent layer of atmosphere. To the naked eye,…

The nights really start to shorten during May, making stargazing that bit harder. This year May sees the planet Jupiter located inside the constellation of Libra, the Scales. For those of us in the Northern Hemisphere, its appearance here has a bittersweet taste as it’s now starting to get rather low in our skies, barely scraping 20° of altitude. With Mars and Saturn also sharing a similar, if not worse, low situation, seeing the brighter planets is something of a struggle for mid-northern latitudes at present. Jupiter reaches opposition on 9 May but Ganymede transits Jupiter on 6 and 14 May, either side of opposition, which produces an interesting effect. On 6 May, Ganymede appears to chase its shadow across the planet’s disc. But on the 14th the orientation is…

“When looking at M3, it’s astonishing to realise that you’re observing a gravitationally bound collection of about half-a-million stars” Stats NAME AND CATALOGUE REFERENCE: Messier 3 CONSTELLATION: Canes Venatici OBJECT TYPE: Globular cluster VISUAL BRIGHTNESS: Mag. +6.2 (binocular) DISTANCE: 33,900 lightyears APPARENT SIZE: 18 arcminutes PHYSICAL SIZE: 760 lightyears across BEST TIME TO SEE: 1 Apr 01:00 BST, 1 May 23:00 BST, 1 Jun 00:00 BST BINOCULARS Getting a closer look M3 is a beautiful globular cluster located close to the southern border of Canes Venatici, where it neighbours Boötes. Its position in the sky doesn’t place it immediately near any bright stars or strong shapes, and this may contribute to it being somewhat overlooked. The simplest way to locate it is to draw a line between Arcturus (Alpha (α)…

The Northern Hemisphere’s autumn equinox occurs on 23 September, so this is the time of year when the nights are growing longer at their fastest rate. The full Moon on 25 September is the closest to this equinox making it the Harvest Moon for 2018. The Summer Triangle is beginning to drift west but will continue to remain obvious right up to the end of the year. To the east of the triangle, the stars of autumn are ready to take centre stage. The most obvious pattern here is the Great Square of Pegasus. Despite being neither strictly a square, nor formed from four stars in Pegasus, it’s a distinctive pattern that can be used to locate other stars and constellations. The square and the circlet The Square’s sides are…

The early evening sky is dominated by Pegasus, with the Great Square of Pegasus creating a large void among the stars. To the south and southeast of the Great Square is an ill-defined region of sky known informally as The Sea. It gets this name because it contains a number of waterrelated constellations. To the east, southeast and south of the Great Square sits Pisces, the Fish, most notable because of the Circlet located south of the Great Square. Southwest of Pisces lies Aquarius, the Water Bearer. Although generally brighter than Pisces, Aquarius is a large, sprawling and ill-defined constellation. The most prominent pattern here is the Water Jar, sometimes referred to by its more contemporary title: the Steering Wheel. Southwest of Aquarius is Capricornus, the Sea Goat. This is…

STEP 1 First cut the tube to length – 150mm is ideal. A ring of tape around the tube will help you ensure each end is cut square, as will holding the tube in a vice. Tidy the ends up with abrasive paper and roughen the surfaces in preparation for gluing. STEP 2 Use dividers to scribe a disc of the same diameter as your tube on black plastic, although a compass and pencil will do an adequate job. Repeat this step with the white plastic. Make a clear centre mark on both of the discs. STEP 3 Cut out the discs as neatly as you can. It pays to use small, sharp scissors, such as those you might use to cut your fingernails, as these will make it easier…