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44 Articles

This is your complete stargazing companion for the whole year, where you’ll find all the info you need to discover the best sights in the night sky, every season. The month-by-month guide reveals what to look for and when. It includes detailed sky charts to lead you through the stars and galaxies. Discover how to identify constellations such as Orion, Cancer, Scorpio, Pegasus, Andromeda and Taurus. Find out the best times to see incredible meteor showers, or moons transiting across their parent planets. And don’t miss the chance to see oppositions and rare conjunctions. If you’re keen to know more, then have a read of our articles on getting to know the Moon and simple stargazing activities to get kids interested in the night sky. Or take a look at…

Get to know the NIGHT SKY

For more about getting started with stargazing, check out The Sky at Night programmes on iPlayer now. With memories of Christmas beginning to fade, and the Sun still setting late afternoon, many people will be looking to the sky and wishing they knew more about what’s ‘up there’ – especially if there was a telescope under the Christmas tree. If this is you and you still haven’t a clue how to use that telescope, don’t be disheartened. After all, the night sky won’t be completely alien. You’ll have seen the Moon countless times before, perhaps while loading up the car at the supermarket. You want to dress like one of the rosy-cheeked children playing in the winter snow from a vintage Ladybird book No doubt you’ll have spotted a bright…

Get to know the NIGHT SKY

Planetarium apps

Stellarium Mobile Free It’s missing the whistles and bells found on other apps, but Stellarium’s simulation of the night sky is beautifully realistic and gives a true impression of what the sky looks like. SkySafari The free version of this feature-packed planetarium app gives you all the information you need to plan your observing sessions, and enjoy eclipses and other astronomical events. Star Tracker A basic app that will help you identify stars, constellations and planets as you sweep your phone or tablet around the night sky. Beautiful graphics, but slightly annoying music. Mobile Observatory Free A powerful app with so many features it’s more like a full PC software package. Its renders of the night sky are realistic and useful for showing astronomical events in advance. Heavens-Above A very…

Planetarium apps

Getting kids involved

One of the best things about stargazing is that it isn’t just a hobby for adults, children can enjoy it too. There are several fascinating things in the January abd February sky which they can find themselves without too much trouble, or can be guided to quickly with a little hint. First of all, as soon as you get to your observing site, ask your youngsters if they can find the ‘Red Planet’. Give them the clue that it’s a bright reddish-pink object, and they should be able to locate the planet Mars shining brightly over in the southwest. Next, once their eyes have dark-adapted, ask them to look for Orion’s Belt – with the advice that it looks like three blue-white stars close together in a line. It won’t…

Getting kids involved

Set out on a star hike

On the trail of the Pole Star Beginners are often shocked to learn that the Pole Star (Polaris) is not the brightest star in the sky and struggle to find it. Thankfully you can star-hop to it from the Plough (Ursa Major) using the two ‘pointer stars’ on the far side of its bowl, which point straight towards Polaris. Let’s get Sirius Whatever the time of night, like a mossy signpost on the corner of a country lane, Orion’s Belt will always point you towards Sirius. Think of it as an arrow pointing both left and right. Follow it downwards to the left and you’ll go straight to Sirius, twinkling low in the sky just above the horizon. Finding the Hyades and the Pleiades star clusters If you extend Orion’s…

Set out on a star hike

STARGAZING for kids

Stargazing with children is a joy if you tackle it in the right way. It’s never too early to start exploring the night sky. Here is our quick guide to making the most of it. Try a mix of activities and don’t worry if things don’t go the way you planned. Let your child lead the way and listen to their questions. Never be afraid to answer with “I don’t know, but that’s a brilliant question. Let’s look it up together.” If they’re struggling, prompt their interest by asking them about what they can see, or what they already know. Build on their curiosity, but don’t overwhelm them with too much information. Everyone learns better through play, so have fun! Choose the right equipment Having the right accesssories makes a…

STARGAZING for kids

Summer is a great time to try solar observing with kids. Keep them from looking directly at the Sun however, particularly if you're using magnification. Eclipse glasses are one option, but the safest way for kids to observe the Sun is with a projection box. To make one, take a long fully enclosed cardboard box and cut a hole in one of the longest sides, big enough to stick their head through. Stick a sheet of white paper over the end they will face. On the opposite side, behind where their head will be, make a pinhole high up. Then stand them facing away from the Sun with the pinhole pointing at it. The idea is for sunlight to travel over their head and project onto the paper. You can…

The complete guide to TELESCOPE MOUNTS

Agood telescope mount is the bedrock that any decent observing or imaging setup is built on. In this guide, we’re going to explore everything you need to know about mounts, starting with the basics – what they are, what they do and why you should think carefully about which type you choose when buying your first scope. At its most basic, a mount has to do two things: one, hold your telescope securely; and two, allow you to move the telescope so that it can be pointed precisely at the objects in the night sky you want to observe. Most mounts achieve the first requirement (holding your telescope securely) using a combination of two elements: a tripod, with legs made of either wood or metal, and what’s known as the…

The complete guide to TELESCOPE MOUNTS

How to polar align an equatorial mount – the basics

1. Orientate the tripod and mount head First, set up the tripod; one of its legs may be marked to indicate that it should be pointing north. Attach the mount head securely to the tripod, making sure to place it in the starting configuration advised by the manufacturer – for example, with the polar axis pointing north. 2. Set the polar axis Next, check that the altitude of the polar axis is set to your latitude – that is, that the axis (the blue arrow and line above) is pointing towards the North Celestial Pole. If it’s not, this can usually be done by carefully tweaking the altitude adjustment knob located at the base of the mount head. 3. Orientate the polarscope’s reticule The polarscope reticule now has to be…

How to polar align an equatorial mount – the basics

Choosing a beginner’s mount

How portable does it need to be – will you need to carry the mount? Consider where you’ll be using the mount most. If you’re going to be travelling to a dark-sky site you may find that lugging around a large equatorial mount will become tiresome. A smaller, portable tracking mount or a lightweight altaz setup could be more in line with your requirements, especially if you aren’t up to lifting heavy loads. What sort of observing will you be doing? Your choice of night-sky target may have a bearing on what type of mount you opt for. If you intend to do solely visual observing of faint objects, it’s probably better to opt for a simpler, less expensive, mount design and spend any money you save on bigger or…

Choosing a beginner’s mount

Take your Lunar OBSERVING FURTHER

The Moon is a fascinating object to observe. Big, bright and easy to find, it’s sometimes taken for granted in favour of what are perceived as more challenging astronomical targets. Yet, on our doorstep is a rich world just waiting to be explored. In this guide we’re going to take a look at some of the aspects which are important for getting the best out of your lunar observing sessions. We’ll introduce the basics of getting around the Moon, look at some of the features visible and extend out to see how it interacts with the surrounding sky. So dust off your telescopes, we’re going to the Moon!…

Take your Lunar OBSERVING FURTHER

Finding your way

Introducing selenographic latitude and longitude, and lunar prime meridian Lunar features are located using selenographic latitude and longitude, which are similar to latitude and longitude on Earth. (‘Selenographic’ means ‘applying to the Moon’ in the same way that ‘geographic’ means ‘applying to Earth’.) Latitude is measured in degrees north and south of the Moon’s equator. Longitude is measured east and west of the lunar prime meridian, which is a line joining the Moon’s north and south poles. This used to be described as passing through crater Mosting A, but now is defined as the mean central north-south line seen from Earth. It doesn’t always appear centrally due to the effects of libration. East becomes west – why the cardinal points on the Moon are different to the rest of the…

Finding your way

What it will look like

The Moon is large and close enough to present a surface which can be explored with the naked eye, binoculars or through a telescope. To the naked eye and binoculars, the Moon’s orientation with north up offers west on the left and east on the right. Through a scope, its orientation will vary depending what arrangement you have at the eyepiece and on the type of telescope. The Moon’s surface shows lots of fine detail, especially when the terminator is nearby. The ability to resolve detail depends on the size of your telescope, seeing conditions and using an appropriate magnification. You can use a simple formula to work out a telescope’s resolving power in arcseconds: R = 120 ÷ d, where d is the diameter of your telescope in mm.…

What it will look like

Targets to observe

Clair-obscur effects Clair-obscur effects are when light and shadow areas on the Moon’s surface appear as something familiar. They’re often time critical and only appear when the terminator is at a specific co-longitude when the Moon is above the horizon. Popular examples are the Lunar X and V, when it looks as if there are two giant letters visible on the lunar terminator. Others are more intricate and difficult to glimpse, such as Cassini’s Moon Maiden, Gruithuisen’s Lunar City and the Face in Albategnius. Banded craters Craters that appear to have dark or light radial lines within their walls are known as ‘banded craters’. There are many of them visible across the Moon’s disc. Typically small in size, they’re great for observing with a telescope and of interest to organisations…

Targets to observe

Lunar occultations

When the Moon is in its fuller phases, it can appear large and dominant. However, in reality it’s quite a small object in the sky, around just half-a-degree across. Compare it to the width of your little finger at arm’s length, which will cover it easily. As it moves around the sky, the Moon covers background stars in events called lunar occultations. Timing these events used to be very important for working out the position of the Moon and the profile shape of its edge. As it’s small, a lunar occultation of a bright star or planet isn’t that common. Occultations of dim stars do happen reasonably frequently though. As the Moon moves east across the sky, occultations caused by a waxing Moon have the background object disappearing behind the…

Lunar occultations

Celestron AstroMaster LT 60AZ refractor

The AstroMaster is a refractor and looks like ‘a proper telescope’ – by that we mean it’s the traditional telescope-on-a-tripod setup. The kit is robust but lightweight and only comes in two main parts, allowing for quick and straightforward assembly. We needed a screwdriver, which is a slight minus, but it is still ready in minutes. The included eyepieces each provide sharp views of stars and great lunar detail with minimal distortion at the edges. The tripod is light and, while the equipment tray provides stability, care is needed not to nudge and move the setup when it’s in use. The supplied smartphone adaptor really grabbed our attention, it will allow users to dabble with astrophotography as well as delve into the world of astronomy. This will enhance the experience…

$Celestron AstroMaster LT 60AZ refractor$

Meade LightBridge Mini 130mm

This lightweight, tabletop Dobsonian is shipped already assembled and is well packaged for protection during transit, with a smaller box containing a red-dot finder, two eyepieces (26mm and 9mm), instructions and Meade’s Autostar planetarium software. With a 5-inch aperture, its eyepieces are 1.25-inch fit and give magnifications of 25x and 72x; in other words, low- and medium-powered views. The finder is a zero-magnification variety and the brightness of its red dot is adjustable, though we found that the lowest setting was best so as not to overpower the view. The single-arm mount delivers free movement on both the altitude and azimuth axes, and is easy to operate. The telescope tube attaches via a Vixen-style clamp and can be removed if needed. This allows you to opt for an alternative mount…

Meade LightBridge Mini 130mm

Unistellar eVscope

Most small scopes don’t have a great deal of light grasp and will not produce detailed images like those often found on their nicely designed boxes. But the Unistellar eVscope challenges that, while giving an insight into what the future of visual astronomy could look like. The eVscope marries a Sony IMX224 sensor with a 4.5-inch, f/4 reflector and an electronic eyepiece, alongside cutting-edge electronics and computing. The telescope tube sits on a single-arm computerised altaz mount attached to a sturdy, adjustable height tripod. The unusual position of the eyepiece creates a more comfortable viewing position and experience; instead of collecting light from a secondary mirror, the eyepiece receives the signal electronically, meaning it doesn’t have to be placed higher up the tube. Plus, it delivers impressive colour results. We…

Unistellar eVscope

Altair 150EDF apochromatic doublet refractor

Size and scale With the dew shield and focuser extended, the 150EDF is 140cm in length and weighs around 10kg, but we found it to be quite manageable and we mounted it singlehandedly. Accessories like cameras or diagonals add length and weight and help to counterbalance the front-heavy scope. Dew shield The dew shield protects the objective lens from the unwanted effects of dew and stray light. It can be fixed in place with an Allen key (not supplied) and lengthens the scope by 22cm, making a difference to its size and balance. Tube rings The 150EDF is supplied with well-machined rings, a fitted Vixen-style dovetail bar on the bottom and a rounder-style bar on top. This acts as a carrying handle or an accessory-mounting rail with multiple fitting points.…

$Altair 150EDF apochromatic doublet refractor$

Canon EOS Ra astrophotography camera

Touch-screen sensitivity When touch-screen imaging is enabled, we were amazed at how lightly we needed to touch the LCD screen to take a shot – a light tap rather than a firm prod. There was no risk of nudging the camera to take an exposure, or while changing ISO and exposure settings. Live View The Canon Ra’s Live View function is outstanding for many reasons, but not least because of its clarity and sensitivity in low light. We were able to clearly see nebulae and galaxies via Live View without the need to take an image, saving us time when locating and positioning objects in frame. Full-frame The Canon Ra’s 30MP full-frame sensor improves low light performance and image noise (unwanted artefacts) at a high ISO. At 36 x 24mm…

Canon EOS Ra astrophotography camera

Orion Monster Parallelogram Mount and GiantView 25x100 binoculars kit

Fully multicoated optics Broadband multicoatings increase light throughput and also reduce the likelihood of internal reflections forming ghost images. They allow the maximum amount of light collected by the large objective lenses to pass to your eyes, giving you maximum brightness with a minimum of distracting ‘ghosts’. Locking lever For security, it is essential that the attachment of the mounting post of these heavy binoculars cannot loosen while they are in use. The hand-wheel on the mounting bracket can give you reasonable tightness, but the locking lever, with mere thumb pressure, provides the extra security that you need. Individual eyepiece focusing For astronomical use, individual eyepiece focusing is considered to be superior to centre-focusing, largely because it is far less easy to accidentally change the focus. Once you are focused,…

Orion Monster Parallelogram Mount and GiantView 25x100 binoculars kit

2-3 & 3-4 JANUARY Peak of the Quadrantid meteor shower 9-14 JANUARY Mercury, Jupiter and Saturn lie close together in a post-sunset formation 11 JANUARY Morning Venus and a waning crescent Moon are in conjunction 20 JANUARY Mars and Uranus are 1.6º apart this evening 25 JANUARY Moon occults the southern two-thirds of the open star cluster M35 this evening Januaryat a glance The New Year brings excitement for the astronomical wonders that lie ahead. This month we see the rise and fall in rates of the annual Quadrantid meteor shower, somewhat compromised by a bright waning gibbous Moon, on the nights of 2-3 and 3-4 January After the spectacular opposition of Mars last October, 2021 finds the planet moving from Earth and fading in brightness. There’s still plenty to…

3 FEBRUARY Orion is well placed in a dark sky 11 FEBRUARY Venus and Jupiter are just half a degree apart in the morning sky 12 FEBRUARY A thin waxing Moon is visible tonight 21 FEBRUARY The Jewelled Handle effect is visible on the Moon this evening 28 FEBRUARY Mars is approaching the Pleiades February at a glance The shortest month of the year still has Orion in charge of the early evening. His reign is threatened by a group of fainter constellations to the east, nudging the Hunter and his entourage to the west later in the night. The seven main stars of Orion are very identifiable. His southwest corner is marked by the bright blue supergiant Rigel (Beta (β) Orionis). Compare Rigel’s colour with orange Betelgeuse in the…

CONSTELLATION OF THE SEASON SPRING: Hercules

Hercules, the Strongman, occupies a large area of sky between the kite-shaped constellation of Boötes, the Herdsman and the small, compact summer constellation of Lyra, the Lyre. It shares this area with the pretty semi-circular pattern known as Corona Borealis, the Northern Crown. Despite occupying this prominent position in the sky, Hercules is not immediately obvious. Most of the constellation’s stars are faint and there is a distinct lack of strong patterns, save for one famous asterism known as the Keystone. This is formed of Epsilon (ε), Zeta (ζ), Eta (η) and Pi (π) Herculis and is easily located as long as you can identify the two bright stars which are the alpha members of Boötes and Lyra. These are Arcturus (Alpha (α) Boötis) and Vega (Alpha (α) Lyrae). Imagine…

CONSTELLATION OF THE SEASON SPRING: Hercules

3-4 MARCH Mars passes south of the Pleiades 4 MARCH Asteroid Vesta is at opposition in Leo 14 MARCH A thin Moon is visible after sunset 19 MARCH Mars, the Moon and Aldebaran form a line 28 MARCH Bright perigee full Moon, or supermoon March at a glance At the start of March the Red Planet, Mars, can be seen passing to the south of the Pleiades open cluster. Closest approach will be during the evening of 3 March, when the planet will be separated from the cluster’s centre by 2.7º. During March the centre of the Sun’s disc appears to cross the celestial equator heading south to north. This instant occurs at 09:37 UT on 20 March marking the Northern Hemisphere’s spring or vernal equinox. For those south of…

13 APRIL A beautiful 2%-lit waxing Moon lies low in the west shortly after sunset 18 APRIL The 27%-lit waxing Moon occults M35 from 01:15 BST until setting 22 APRIL Peak of the Lyrid meteor shower (moonlight will interfere) 25 APRIL Venus and Mercury lie 40 arcminutes apart in the evening sky 26 APRIL Mars lies near M35 in the evening April at a glance The waxing crescent Moon is well positioned at this time of year, something beautifully illustrated over the evenings of 13, 14 and 15 April. On 13 April the 2%-lit waxing lunar crescent appears low in the west shortly after sunset. As the sky darkens, look out for its weakly glowing night side, illuminated by reflected light from planet Earth. The following evening, now 6%-lit, the…

6 MAY Eta Aquariid meteor shower peaks this morning 12 MAY Evening Venus lies near a <1%-lit waxing crescent Moon 14 MAY Ganymede’s shadow partially eclipses Io from 04:43-04:53 BST 24 MAY Noctilucent cloud season begins 28 MAY Mercury and Venus lie half a degree apart this evening May at a glance Although the length of night decreases significantly through May, there’s still a lot to see in the sky. Jupiter reaches equinox on 2 May and around this time it’s possible to see interactions between its four largest satellites, the Galilean moons. For example, between 04:43 and 04:53 BST on 14 May Ganymede’s shadow partially eclipses the moon Io. As the Moon tracks around the sky throughout the course of a month, it shows some interesting effects. From 23:55…

CONSTELLATION OF THE SEASON SUMMER: Aquila

Aquila, the Eagle represents the legendary creature which was used to torture Prometheus, the Titan, who stole fire from the Gods and gave it to man. Prometheus was chained to a rock for his deed and attacked by the bird-of-prey. The Eagle was an emblem of Zeus, the King of the Gods. Encountering the chained Titan, it ripped out Prometheus’s liver. But the Titan was immortal and his liver grew back overnight only for him to endure the agony on every following day. Prometheus was eventually freed by Hercules, who killed the Eagle using the arrow Sagitta. Aquila appears like a misshapen ‘X’. The brightest star in the constellation is Altair (Alpha (α) Aquilae), easily identified because it marks the southern tip of the asterism known as the Southern Triangle.…

CONSTELLATION OF THE SEASON SUMMER: Aquila

ALL MONTH Noctilucent clouds may be visible 5 JUNE Io’s and Ganymede’s shadows are in transit before Jupiter rises at 01:30 BST 10 JUNE Partial annular solar eclipse visible from the UK 12 JUNE Io’s and Ganymede’s shadows are both in transit on Jupiter from 03:40 BST 21 JUNE Northern Hemisphere’s summer solstice at 04:32 BST June at a glance For a month with such short nights, there’s a lot going on in June. All through the month it may be possible to see noctilucent clouds (NLCs). If there, these highaltitude ice clouds shine by virtue of reflected sunlight and may typically be seen 90-120 minutes after sunset low above the northwest horizon, or a similar time before sunrise low above the northeast horizon. There is no guarantee that an…

ALL MONTH Noctilucent clouds may be visible 9-10 JULY Thin moon on morning of 9th and evening of 10th 13 JULY Venus and Mars just 0.5º apart 12, 17, 25 & 29 JULY Jupiter moon and shadow events 28 JULY Saturn’s rings brightening due to opposition effect July at a glance July nights are short, never achieving full darkness at the start of the month. But they do lengthen as the month progresses, proper darkness returning slowly to parts of the UK. Like June, July is noctilucent cloud (NLC) season and it’s very much worth keeping an eye out for displays low above the northwest horizon 90-120 minutes after sunset, or a similar time above the northeast horizon before sunrise. As darker skies return, the giant form of the Summer…

2 AUGUST Saturn reaches opposition 11-12 & 12-13 AUGUST Favourable Perseid meteor shower peak 19 AUGUST Jupiter reaches opposition 22 AUGUST Double moon and shadow transit on Jupiter 31 AUGUST Possible outburst of Aurigid meteors August at a glance There are favourable conditions for the Perseid meteor shower this year, with the peak period expected between 20:00-23:00 BST on 12 August. A watch on the night of 11-12 August will reveal the ramp up to maximum, and 12-13 August will reveal the ramp down. There also might be an Aurigid meteor outburst at the end of the month, with the peak night on 31 August-1 September, when the radiant is near ThEta (η) Aurigae. As nights draw in, the summer constellations are visible under darker sky conditions earlier in the…

CONSTELLATION OF THE SEASON AUTUMN: Perseus

Perseus the Greek Hero, is a compact Northern Hemisphere constellation. It sits southeast of Cassiopeia and east of Andromeda, two constellations linked to Perseus in mythology. Cepheus and Cassiopeia were king and queen of Ethiopia. Andromeda was their daughter. Cassiopeia claimed Andromeda was more beautiful than the Nereid sea nymphs, a declaration which angered sea god Poseidon. In retribution he sent floods and the sea monster Cetus to ravage the Ethiopian coast. To appease Poseidon, Andromeda was chained to a rock as a sacrifice to Cetus. Riding the flying horse Pegasus, Perseus went on a mission to cut off the head of the Gorgon Medusa, whose stare turned any living creature to stone. Mission successful, Perseus used the head to turn Cetus to stone, rescuing Andromeda and eventually marrying her.…

CONSTELLATION OF THE SEASON AUTUMN: Perseus

2 SEPTEMBER Morning occultation of Mebsuta (Epsilon (ε) Geminorum) 6 AND 7 SEPTEMBER Two excellent thin Moon spotting opportunities 11 SEPTEMBER Asteroid 2 Pallas at opposition 17 SEPTEMBER Callisto’s shadow is in transit 20 SEPTEMBER Harvest Moon for 2021 September at a glance The equinox on 22 September is good news for Northern Hemisphere stargazers, marking the time when nights are increasing in length at their maximum rate for the year. There’s plenty to observe this month too. Jupiter’s outer Galilean moon Callisto transits the planet from 02:33 BST on 1 September, Jupiter setting before the transit concludes. Then, on 17 September Callisto’s shadow transits the planet from 23:43 BST, Jupiter again setting just before the event ends. Earlier this night Callisto transits Jupiter as the sky darkens, leaving the Jovian…

4 OCTOBER A rare double transit of Ganymede’s and Callisto’s shadows on Jupiter 5 OCTOBER Good opportunity to spot the thin waning crescent Moon 8-9 OCTOBER Favourable peak of the Draconid meteor shower 25 OCTOBER Mercury reaches a favourable western elongation 29 OCTOBER Venus reaches its greatest eastern elongation October at a glance Long, dark October nights are great for stargazing, and Jupiter offers up some amazing satellite transit events this month. On 4 October there’s a rare opportunity to see a double transit of Ganymede and Callisto’s shadows. The event starts in daylight at 18:00 BST as Callisto’s shadow begins to transit. Ganymede will also be in transit at this time, leaving Jupiter’s disc at 19:19. Ganymede’s shadow joins Callisto’s at 19:55. The event ends at 22:25 as Callisto’s…

3 & 4 NOVEMBER Mercury lies near the waning crescent Moon this morning 4 NOVEMBER Uranus at opposition 11 NOVEMBER Lunar X and V, clair obscur effects, are visible 19 NOVEMBER Partial lunar eclipse at moonset 27 NOVEMBER Dwarf planet Ceres at opposition November at a glance This month kicks off with transits. There’s another chance to spot Callisto transiting Jupiter on 6 November, the event starting around 16:45 UT and ending at 21:20 UT. On 16 November, it is Ganymede’s shadow doing the transiting from 19:08-22:36 UT. Earth’s shadow causes a partial eclipse of the Moon on 19 November, but the main eclipse begins at 07:18 UT, a few minutes before moonset. It should be possible to see the Moon’s northwest limb darken as it approaches the northwest horizon.…

CONSTELLATION OF THE SEASON WINTER: Canis Major

Canis Major, the Great Dog, is one of Orion’s hunting dogs. The other is Canis Minor, the Little Dog, located further to the north. Both constellations have bright alpha stars. Canis Major’s is Sirius (Alpha (α) Canis Majoris) while Procyon (Alpha (α) Canis Minoris) holds this position within Canis Minor. Interestingly, both stars are binary systems and the fainter components are both white dwarf stars – the hot dense cores of low mass stars which have ejected their outer layers into space to form planetary nebulae. Any similarity ends here: Canis Minor consists of two stars typically joined by a single line on charts, while Canis Major is more complex and appears as the outline of a dog standing on its hind paws, leaping up towards its master, Orion. Sirius…

CONSTELLATION OF THE SEASON WINTER: Canis Major

3 DECEMBER Thin Moon spotting opportunity this morning 14 DECEMBER Geminid meteor shower peak this morning 24 DECEMBER Lunar occultation of Eta Leonis from 04:19-05:04 UT 29 DECEMBER Six planets visible in the sky this evening 31 DECEMBER Mars lies near its rival, Antares, in the morning sky December at a glance The big annual event for December is the peak of the Geminid meteor shower. This reliable performer delivers around 140-150 meteors per hour. A bright waxing gibbous Moon interferes with the display on the night of 13/14 December but sets at 03:00 UT, leaving three hours of dark sky for the UK to enjoy the run up to maximum, predicted for 07:00 UT on 14 December. The Moon is full on 19 December and at this time of the…

Project 1: Classifying Lunar Craters

Observing the Moon is a fascinating way to spend a morning or evening. There’s so much to see, from large lava plains, mountain ranges, valleys, cracks in the lunar surface and, of course, craters. Lots and lots of them! Craters range from being so small you can hardly see them even through a big telescope, to so large that they contain their own crater families inside. Making sense of it all is quite daunting, but systems do exist. One of the best categorisation schemes was established by Chuck Wood and Leif Anderson of the Lunar & Planetary Laboratory. They devised five broad categories of crater to account for around 99% of all lunar craters. The categories are as follows: In this project all you need to do is categorise as…

Project 1: Classifying Lunar Craters

Project 2: Jupiter’s Mutual Events

Jupiter experiences an equinox at the start of May, caused by its axis of rotation being inclined to its orbital plane around the Sun. Every planet in the Solar System has this. The Earth’s axial tilt, or obliquity, varies minutely each year but is approximately 23.4º. Other planets have different axial tilts, as shown below: These figures are based on the assumption that all planets rotate anti-clockwise looking down on their north (positive) pole. Venus and Uranus have retrograde (backward) rotations so technically, their tilts are larger than 90º. Jupiter’s axial tilt is small at 3.13º, but large enough to affect our view of the Galilean moons Io, Europa, Ganymede and Callisto, bodies which have orbits that are only slightly inclined to Jupiter’s equatorial plane. From Earth, the moons’ orbital…

Project 2: Jupiter’s Mutual Events

Project 3: Recording Sunspots

The Sun has an 11-year visual activity cycle. During 2020, activity levels dropped to that associated with solar minimum, when things get really quiet. Activity should start to show signs of recovery in 2021 and this is a good time to dust off your solar observing kit, getting ready for the slow crawl to solar maximum, expected sometime between 2023 and 2026. Before starting, it’s necessary to cover some essential safety guidelines. The Sun is dangerous and can do you and your equipment harm. It’s essential to be safety conscious about it at all times and to double-check everything you do. You should never look directly at the Sun without adequate eye protection. All optical equipment must similarly be protected using certified solar safety filters. Also be aware that accessories…

Project 3: Recording Sunspots

HOW TO Collimate a Newtonian telescope

Newtonian reflector telescopes are perennially popular for amateurs due to their relatively low cost for any given aperture and their naturally good colour correction. But due to the loose way in which a Newtonian’s two mirrors are typically held, this design of telescope can lose its optical alignment relatively easily, especially when compared with more robust telescope designs like refractors. The process of bringing the mirrors back into optical alignment is referred to as collimation. Collimation is about getting a Newtonian’s ‘sweet spot’ in the centre of the view through the eyepiece. This sweet spot is where stars appear sharpest: it’s the circular area on a Newtonian’s main mirror where light is focused to maximum resolution. Outside the sweet spot star images appear larger and get distorted into V-shapes. This…

HOW TO Collimate a Newtonian telescope

HOW TO Protect your eyepieces

All your optical equipment deserves to be maintained and handled carefully so that it performs at its best. But your poor eyepieces take the brunt of abuse, as they are exposed to a natural source of unwanted contaminants and risk – you! Just handling them deposits fingerprints and grease on the body of the eyepiece and it is all too easy to accidently leave a fingerprint on the optics themselves. Simply placing your eye in position will transfer tiny amounts of grease onto the lens, as well as fragments of eye lashes, dry skin and traces of cosmetics. Dust, pollen and other contaminants will also collect on the optical surfaces. All of this is bad news for the antireflection coatings on the lens surface and ultimately the quality of the…

HOW TO Protect your eyepieces

HOW TO Make a smartphone holder

Asmartphone holder will help you to take great astrophotographs using the camera on your smartphone. Unlike some commercially made versions, this particular design can be adapted to suit a wide range of smartphone models. The method of imaging that smartphone astrophotography uses is called ‘eyepiece projection’ or ‘afocal projection’ because it involves taking a photograph through a telescope’s eyepiece (unlike ‘prime focus photography’ where the camera replaces the eyepiece). The camera lens must be firmly supported in a similar position to the eye when visually observing. This is where our adaptor comes into play. The phone is held between two pairs of clamps mounted on a rigid baseplate. This has a nosepiece which securely inserts into a tube that clamps to your scope’s eyepiece. These two parts are made from…

HOW TO Make a smartphone holder

APERTURE The diameter of a telescope’s light-gathering main lens or mirror. The bigger the aperture, the brighter and more detailed the image. AVERTED VISION A technique for observing faint objects through a telescope. It involves viewing slightly to the side of the object, allowing its light to fall on an area of the eye more sensitive to light. BINARY STAR A system of two stars that orbit a common centre of gravity. The brighter star is classified as the primary; the dimmer is the secondary. CELESTIAL EQUATOR A projection of Earth’s equator into space. CELESTIAL SPHERE The projection of the night sky on to an imaginary sphere around Earth. The astronomical coordinates of right ascension and declination are also mapped onto this sphere. COLLIMATION The process of aligning the optical…

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