Walk - The Magazine of the Ramblers » astronomy http://www.walkmag.co.uk The magazine of the Ramblers Mon, 13 May 2013 05:47:38 +0000 en-US hourly 1 http://wordpress.org/?v=3.5.1 Brian Jones: Comets & Planets http://www.walkmag.co.uk/blogs/brian-jones-comet-pan-starrs/ http://www.walkmag.co.uk/blogs/brian-jones-comet-pan-starrs/#comments Tue, 12 Mar 2013 09:33:37 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=24505 This Spring, the evening twilight sky will be playing host to Comet PanStarrs. The fact that this particular comet appears to be making paying its first visit to the inner reaches of the solar system suggests that it might become a fairly conspicuous object. Comets, however, are very unpredictable and we can only wait and see. Comet PanStarrs should become visible from around mid-March.

PanStarrs-2013
On 12/13 March, the crescent Moon will be located quite close to the comet and should help you to track the comet down. From then, and over the next few weeks, Comet PanStarrs will make its way slowly northwards through the constellations, passing a little way from the Andromeda Galaxy (M31) on 4 April and between the two bright stars Schedir and Caph  in Cassiopeia around 20 April. Up to this time, and given clear skies above the northern horizon, Comet Pan Starrs may be visible to the unaided eye and should, hopefully, be fairly easy to track down with binoculars. By the time it passes Alrai in Cepheus on 13 May it will be below naked-eye visibility and, from our viewpoint on Earth, heading towards the star Kochab in Ursa Minor, the Little Bear, which it should reach by around mid-June. At this point, Comet PanStarrs will be faint and probably only visible through a telescope.

As far as the planets are concerned, over the next couple of months we have both Jupiter and Saturn on show, Jupiter being prominent in the south-western evening sky in the constellation Taurus after sunset during February, March and early-April. The crescent Moon lies fairly close to Jupiter, and the bright star Aldebaran, on the evening of 17 March. The orbit of Jupiter then carries it away from Aldebaran, and on 14 April the crescent Moon is again seen close to the planet. Saturn, on the other hand, rises at around 10pm during March evenings and even earlier during April. The Moon, a few days past its full phase, can be seen near to Saturn on the evening of 30 March, and on 25 April Saturn will be located a little way to the north east of the Full Moon. Saturn reaches opposition (opposite the Sun as seen from Earth) on 28 April, at which point it will be visible throughout the night.

Until the next blog . . . happy star (and comet) gazing!

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Brian Jones: Spring stars http://www.walkmag.co.uk/blogs/brian-jones-spring-stars/ http://www.walkmag.co.uk/blogs/brian-jones-spring-stars/#comments Thu, 21 Feb 2013 19:14:41 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=23780 Located at or near the overhead point during the spring night sky is familiar shape of the Plough formed from the seven brightest stars in the constellation Ursa Major, the Great Bear. If you follow the line from Merak, through Dubhe, in the ‘bowl’ of the Plough you will reach Polaris, the Pole Star (not shown here), the brightest star in Ursa Minor, the Little Bear. Although not particularly bright, Polaris lies in an area of sky devoid of bright stars and therefore stands out quite well.


To the south of the Plough ‘handle’ are the faint constellations Canes Venatici, the Hunting Dogs and Coma Berenices, Berenice’s Hair and following the curve of the line of stars in the Plough handle as shown will lead you to brilliant Arcturus, the leading star in the constellation Bootes, the herdsman. Continuing the line further towards the south will eventually help you to locate Spica, the main star of Virgo, the Virgin. The other prominent spring group is Leo, the Lion located to the north west of Virgo.

If the sky is fairly dark and clear, you should be able to pick out the small and rather faint constellations Leo Minor, the Little Lion and Lynx, the Lynx, located in the area of sky just to the north of Leo. Clear skies will also be needed to reveal the small constellations Corvus, the Crow and Crater, the Cup to the south of Virgo. An even bigger challenge is to pick out the tiny Sextans, the Sextant, found just to the south of the star Regulus in Leo and the long and winding constellation Hydra, the Water Snake. The brightest star in Hydra is Alfard, found just to the west of Sextans, the rest of the group winding its way across the southern sky, for the most part immediately above the southern horizon. Try finding Alfard and then, with binoculars, see how far you can travel along the body of the Water Snake! R Hydrae, shown here just below Spica, is a long-period variable star – more about that, and the constellation Hydra, in a future blog.

Until then… happy stargazing!

Don’t miss Brian’s special column on the approaching comet due in March 2013!

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Brian Jones: Wintry skies http://www.walkmag.co.uk/blogs/brian-jones-winter-2012/ http://www.walkmag.co.uk/blogs/brian-jones-winter-2012/#comments Thu, 13 Dec 2012 12:26:36 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=23410 The winter night sky contains a large number of brilliant stars, making it easier to pick out the various star patterns. Located a little to the east of the overhead point is Capella, the leading star in the constellation Auriga, the Charioteer, a conspicuous group taking the form of a circlet of stars. A little way towards the south east of Auriga is the prominent constellation Gemini, the Twins, with its two leading stars Castor and Pollux particularly prominent, as is Procyon, the leading star of Canis Minor, the Lesser Dog, located a little way to the south of Pollux.

Pride of place in the winter sky, however, goes to Orion, its brightest stars forming a distinctive quadrangle sweeping over the southern horizon. Its brightest stars, Betelgeuse and Rigel, are unmistakeable as is the trio of regularly-spaced stars spanning the central region of the group and forming the Belt of Orion. These three stars act as pointers to two neighbouring constellations. Following the line formed by the Belt of Orion up towards the north west we first of all reach Aldebaran, the leading star in Taurus, the Bull (this group will be covered in a future blog), extending the line further bringing us to the Pleiades, a prominent open star cluster located in the upper reaches of the constellation. Following the line of stars in the Belt of Orion down towards the south east brings us to Sirius, the brightest star in Canis Major, the Greater Dog while just below Orion we see the small gathering of stars forming the constellation Lepus, the Hare.

Rounding off our tour of the winter night sky is the faint constellation Monoceros, the Unicorn (the subject of a future blog), located roughly between the two celestial dogs, and the long and winding trail of faint stars forming Eridanus, the River, stretching away from a point just to the north west of Rigel at the foot of Orion. Eridanus winds its way southwards to a point well below the southern horizon, and much of the constellation is hidden from our latitudes although, given clear dark skies, we can make out the northern reaches of this sprawling group. Binoculars will definitely be a help when trying to pick out Eridanus and Monoceros.

Other celestial sights occurring over the next few months include Venus, which continues to dominate the morning sky and Jupiter, which rises during the early evening over the next couple of months or so and is visible throughout the night. Saturn also makes its presence felt, rising during early mornings in December.

Several meteor showers occur during the next couple of months or so, the most notable of these being the Geminids which are active from around the 6th to 19th of December. Peak activity takes place on or around the 13th and, with New Moon occurring on this date, there will be no moonlight to interfere. Given cloudless skies, time spent checking the shower out around this time could be amply rewarded. The meteors from the Geminid shower are typically fast moving and yellowish in hue and appear to radiate from the region of sky close to Castor and Pollux in the constellation Gemini. The Geminids were first observed during the 1860s, and from that time the hourly rate for the shower has been seen to be slowly increasing, now standing at an average of around 80 meteors per hour. Indeed, hourly rates for this shower have reached 100 or more during recent years so the Geminids are definitely worth watching out for!

Another object worth mentioning is the comet C/2011 L4 PanSTARRS which was discovered in June 2011 with the PanSTARRS telescope located near the summit of Haleakala on Maui in Hawaii. At the time of discovery the comet was located at a distance of around 700 million miles (1.1bn km) from the Sun, between the orbits of Jupiter and Saturn. Comet PanSTARRS has steadily increased in brightness on its journey towards the inner solar system. It will pass closest to the Earth on 5th March, and to within around 28 million miles (45 million km) of the Sun on 10th March, taking it inside the orbital path of Mercury. This close encounter with our parent star may result in the formation of a very bright coma and tail as material from the comet vaporises, pushing the comet towards peak brightness. Although cometary magnitudes are difficult to predict, it is thought that Comet PanSTARRS could become very prominent as it eventually moves away from the Sun. Visible in the western twilight sky it will be positioned a little way to the left of a very thin crescent Moon on the evening of 12th March which, given clear skies, will present a pretty picture. As it subsequently travels through the constellations Andromeda, Cassiopeia and Cepheus during March, April and May, Comet PanSTARRS has the potential to become a very prominent naked-eye object. Further details will be given in the next blog.

So, even though the evenings are cold, why not take advantage of any clear and moonless skies we have, venture outside and check out the Geminids along with Orion, Taurus and the rest of the winter constellations. Good luck – and happy star gazing!

 

 

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Routemaster in-depth: Make a night of it http://www.walkmag.co.uk/features/routemaster-in-depth-make-a-night-of-it/ http://www.walkmag.co.uk/features/routemaster-in-depth-make-a-night-of-it/#comments Tue, 28 Aug 2012 16:32:28 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=21917 On a night-time walk through Galloway Forest, Paul Lamarra explores the UK’s only Dark Sky Park, where pure, unadulterated views of the galaxies await. Heavens above indeed!

I was feeling more than the usual tension and excitement of the walk ahead as I donned my boots and packed my rucksack in the car park at Glentrool, in the Galloway Forest Park of south-west Scotland.

There were hills on all sides and my aim was to reach the summit of Merrick. At 843m/2,766ft, it is the highest point in the south of Scotland, with views that extend far beyond the Firth of Clyde to the Lakes and Ireland’s Mourne Mountains. Except I would be walking at night, and the views beckoning me on would be those of the stars and inky sky above, rather than mountains in the distance. Merrick, you see, lies at the heart of the 300-square-mile forest park and is one of the darkest places in the world. Which is why it’s the UK’s only officially designated Dark Sky Park – one of just six in Europe – and one of the best places to view the night sky.

Walking at night, despite high-profile advocates such as author Will Self, remains taboo. Darkness is, after all, the refuge of rogues and rascals. So, at just after 9pm, I set off on the very obvious path through waist-high bracken. The sky was grey but not quite opaque, and the half light was diffused so that hillsides and trees were petrified in monochrome.

The cloudy conditions would have to improve if I were to stand any chance of spotting the Andromeda galaxy, the moons of Jupiter or the Milky Way on the outer edges of our own spinning galaxy. Crucially, there would be minimal moonlight to obliterate the stars and planets should the sky clear.

Earlier that day I had met astronomer Mike Alexander, who runs courses at the Galloway Astronomy Centre, near Whithorn. Mike told me that in such a dark spot, the sky would be awash with stars, and the well-known constellations of Orion, the Plough, Cassiopeia and Pleiades would be trickier to pick out.

Beyond the tree line, a proper darkness began to develop. But there was no need to resort to a head torch as my eyes had already grown accustomed to the gloom, helped by bobbing white bog cotton acting like cats’ eyes in the failing light. Besides, Merrick’s gently rising and smooth grassy terrain provoked few stumbles.

Island of darkness

On the final slopes it eventually became apparent that the sky wasn’t going to clear. In such circumstances, Mike had suggested I look out for noctilucent clouds – luminous cobwebs that are visible in the deep twilight, formed when water in the upper atmosphere mixes with the vapours of meteors fizzling on contact with the Earth’s atmosphere.

Alas, I witnessed neither such clouds nor the green flash that can occur in the final moments of sunset (probably caused by atmospheric dispersion). Instead, I watched as the cooling sun appeared to be swallowed by the hellish lower jaw of the Arran Mountains, and I shivered as the perfectly semi-circular outline of the rocky island of Ailsa Craig resembled – just for a moment – the sun’s satanic alter ego.

In an instant it was dark. Very dark. In fact, on the Sky Quality Meter’s scale of 1 to 25 – a measurement accredited by the International Dark Sky Association, which campaigns to minimise light pollution – Merrick reads 23.6. That’s almost 100 times darker than Glasgow and similar to the light levels in a photographic darkroom. Very sparsely populated, there are few sources of artificial light here, and to look out from Merrick is to look out over an island of darkness. Only the distant orange glows of Belfast and Glasgow compromise the totality.

Pitching a tent, I waited without success until 4:30am for any further stellar light displays. Although the Galloway sky is dark and generally unpolluted, it is unfortunately only clear of cloud on around 140 nights per year. Nevertheless, my first nocturnal exploration had been a thrilling experience and, after catching some sleep in the day, I was ready for another attempt.

Heightened senses

The second evening started rather more promisingly as I set out from the Glentrool Visitor Centre to trace a figure of eight, combining the loops of the river Trool trail and Loch Trool loop – two of four park routes that have recently been reconstructed to make them more accessible.

The Forestry Commission has, where possible, replaced very steep sections with gentler zigzags and eradicated much of the mud. As well as the coast-to-coast Southern Upland Way, there are 27 other waymarked paths that fall within the park’s boundary. The easiest is perhaps the mile-long Bruntis Loch route, which starts from the Kirroughree Visitor Centre; and one of the most challenging is without doubt that to the summit of Cornish Hill (467m/1,532ft), from where there are excellent views of the Isle of Arran and Ben Lomond, nearly 100km to the north.

The new surfaces, although not intended to assist night walkers, do help to make such nocturnal adventures easier. Following the freshly laid gravel into the deeper recesses of the conifer forest, I resisted the temptation to switch on my head torch and relied on my heightened senses.

On occasions it was necessary to feel for the mossy dyke lining of the path with my foot, or reach out for the proximity of branches. Listening rather than looking, I became aware of the sounds of the swaying trees. The monoculture of conifers created a consistent swish, whereas the varied native woodlands of oak, rowan and birch around Loch Trool produced an incoherent cacophony punctuated by hoots.

Ahead of me, on the slopes above the tree line, water tumbling over slabs of granite glinted in the light of the moon and stars. And, when the sky remained clear for long enough, I believe I was able to pick out most of the well-know constellations from the smoky profusion of billions.

Using the binoculars, I was excited to locate the dim white ovoid of the Andromeda galaxy a mere two-and-a-half million light years away. A very keen eye could pick out the fast-moving dot that was the International Space Station. The moons of Jupiter would not rise until 3am.

Winter is the best time to view the night sky, when there is no need to stay up so late, and there are meteor showers promised every month from October through to January. Mike Alexander also reckons that this year will be among the best to view the northern lights.

With any walk there is a tense hope of good views. The difference at night is that the views – in Galloway Forest Park, at least – are potentially out of this world.

Photography: Steve Morgan

*walk_it1

TIME/DISTANCE: Allow 4½ hours for the 12km/7½-mile ascent of Merrick at night – longer if you want to stargaze more extensively.

MAPS: OS Explorer 318; Landranger 77.

FURTHER INFO: Forestry Commission Scotland (✆ 01671 402420, www.gallowayforestpark.com) has produced a free booklet, Scotland’s Stellar Spectacular: A Guide to the UK’s first Dark Sky Park.

routemasterClick here for Walk’s Routemaster guide to a walk in Galloway Forest!

Online exclusive! Extra images from Paul’s nocturnal walks…

Galloway Forest Dark Skies Galloway Forest Park PaulGalloway3-1night2 Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys Galloway Forest dark Skys

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Brian Jones: Autumn stars http://www.walkmag.co.uk/blogs/brian-jones-autumn-2012/ http://www.walkmag.co.uk/blogs/brian-jones-autumn-2012/#comments Tue, 28 Aug 2012 15:06:01 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=22188 The autumn night sky plays host to Cassiopeia, which can be found at or near the overhead point during the months of autumn. A little way to the south of Cassiopeia is the line of stars forming Andromeda. Sirrah, the westernmost star in Andromeda, forms the upper left corner of the adjoining and very conspicuous Square of Pegasus. This huge quadrilateral of stars, located roughly a third of the way to the south from the overhead point during autumn, is a striking feature of the late-summer, autumn and early-winter night sky. If the sky is really dark and moonless you might like to try your hand at counting the number of stars visible to the naked eye within the Square of Pegasus. If viewing conditions are good, you have really keen eyesight, you might spot twenty or more.

Located just to the south east of Andromeda are the two tiny but prominent constellations Triangulum and Aries and extending in a long and meandering line from Andromeda to below the Square of Pegasus is the large but generally faint constellation Pisces, the Fishes.

Staying with the watery theme, bordering the south eastern edge of Pisces is another faint constellation, this being Cetus, the Whale, its tail marked by the fairly prominent star Deneb Kaitos, its name derived from the Arabic for ‘Tail of the Whale’. Deneb Kaitos can be located by following a line from Sirrah, through Algenib (in the Square of Pegasus) a little way towards the south.

By far the most interesting object in Cetus is Mira, a long-period variable star, whose brightness varies from around second or third magnitude (roughly that of Deneb Kaitos) down to around tenth magnitude, which is below the light grasp of all but the most powerful binoculars (for more on magnitudes, see below). The period of variability is around 331 days, during which time the star undergoes a complete cycle of variability. Mira was the first variable star to be discovered and, as is the case with other long-period variables, the period of Mira is by no means constant. Periods ranging from as little as 304 days to as much as 355 days have been recorded.

During late-August and early-September, Mira will be around maximum brightness and so this will be a good time to identify the star. It lies roughly on a line from Eta, Omicron and Alrisha in the neighbouring constellation Pisces, as shown on the chart. Get to know the stars of Cetus and, once you’ve picked Mira out, keep an eye on it over the following few months and watch it as it slowly disappears from view. The name of this star means ‘Wonderful’ which indeed it must have been to the stargazers of long ago who must have often noticed the star, only to watch it disappear and reappear over time.

Our final port of call this time is the bright star Fomalhaut in the constellation Piscis Austrinus, the Southern Fish. Fomalhaut, whose name means ‘Mouth of the Fish’ lies just above the southern horizon during late-evenings in September. It can be found by following a line from Scheat, through Markab, both in the Square of Pegasus and down towards the south as shown here. If the sky close to your horizon is very clear you should spot Fomalhaut and, using binoculars, you may be able to pick out some of the fainter stars in Piscis Austrinus and the neighbouring constellation, the Sculptor, although exceptional seeing conditions would be needed…

…but don’t let that stop you having a go! Until the next blog, happy stargazing

MAGNITUDES

In around 150BC the Greek astronomer Hipparchus divided the stars up into six classes of apparent brightness, the brightest stars being ranked as first class and the faintest as sixth. This system is known as apparent magnitude and classifies the stars and other celestial objects according to how bright they actually appear to the observer. In 1856 the English astronomer Norman Robert Pogson (1829 – 1891) refined Hipparchus’s system by classing a first magnitude star as being 100 times as bright as one of sixth magnitude, giving a difference between successive magnitudes of  5√100 or 2.512. A star of magnitude 1.00 is 2.512 times as bright as one of magnitude 2.00 and 6.31 (2.512 x 2.512) times as bright as a star of magnitude 3.00 and so on. The same basic system is used today, although modern telescopes enable us to determine values to within 0.01 of a magnitude. Negative values are used for the brightest objects including the Sun (-26.8), Venus (-4.4 at its brightest) and Sirius (-1.42). Generally speaking, the faintest objects that can be seen with the naked eye under good viewing conditions are around sixth magnitude, whilst binoculars will allow you to see stars and other objects down to around ninth magnitude or so.

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Brian Jones: Summer sky sights http://www.walkmag.co.uk/blogs/brian-jones-summer-sky-2012/ http://www.walkmag.co.uk/blogs/brian-jones-summer-sky-2012/#comments Tue, 29 May 2012 14:46:43 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=20947 The orbits of the planets Mercury and Venus lie inside that of the Earth, which means that they never appear far from the Sun when viewed from our planet. Indeed, Venus graced our evening skies during spring, being visible as a brilliant star-like point of light in the western sky and setting several hours after the Sun. However, the orbit of Venus is now swinging the planet closer to our parent star (as viewed from Earth) and it will shortly pass between the Earth and Sun. When at these points in its orbit Venus would normally pass either just above or just below the Sun as seen from Earth. As a result, it would generally not be observable, being lost from view in the bright solar glare. However, there are occasions when the lining up of the Earth, Sun and Venus (or Mercury) are more or less exact, and at these times the planet in question can be seen silhouetted against the disc of the Sun.

Such events are known as transits, and on the 5th and 6th of June astronomers and sky gazers will witness a transit of Venus as the orbit of the planet carries it between our planet and the Sun. When this happens, Venus will pass directly between the Sun and Earth and will be visible as a tiny black disc against the Sun. The upcoming transit will actually start shortly after 11.00pm on 5th June, at which time the Sun is below the horizon as seen from the British Isles. As a consequence, only the latter stages of the transit will be visible to British observers, Venus being located near the edge of the solar disc and finally moving away from the Sun a little over an hour after sunrise.

Great care must be taken when observing the Sun, even when the Sun is located low down in the sky either on or near the horizon. Never look directly at the Sun, either with the naked eye or with optical aid, as you may permanently damage your eyesight. The best way to observe the transit is to project an image of the Sun onto a white screen, such as a piece of card. This can be done either by focussing the Sun’s image through a pinhole in a piece of card onto a second piece of card, or by using a telescope or one half of a pair of binoculars to the same effect. If binoculars are used they can be held steady by clamping them to a tripod. If you use a telescope, put a cover over the end of the finder scope so that you don’t accidentally look at the solar disc through it. Never align the telescope or binoculars by looking through them. The best method is to line the binoculars or telescope up in the direction of the Sun (bearing in mind the main lens of the telescope or binoculars should be capped during this process) and then manoeuvre the instrument round until the shadow of the telescope tube or binocular barrel on the screen is perfectly round. Then, keeping your eye away from the eyepiece, uncap the telescope or binoculars and you should see a projected image of the Sun on the screen. If you don’t, then some fine adjustment should bring the image of the solar disc into view. Once you have this, Venus should be visible as a tiny black disc situated near the edge of the solar image. From here, the movement of Venus across the face of the Sun will become noticeable over the period of a few minutes or so.

Transits of Venus are rare and only occur in pairs with an eight-year gap between each, the next pair of transits taking place over a century later. The last transit of Venus was in June 2004. The previous ones were in December 1874 and December 1882 and the next pair will not be seen until December 2117 and December 2125. So, if you miss this one you won’t get a second chance – there won’t be another taking place in your lifetime!

Summer stars

The night sky at this time of year is dominated by the three constellations Cygnus (the Swan), Lyra (the Lyre) and Aquila (the Eagle) which lie close to the overhead point during summer evenings. Particularly prominent is the triangle formed from the bright stars Deneb in Cygnus, Vega in Lyra and Altair in Aquila. Known as the Summer Triangle, this trio of stars is unmistakable and from here many of the other constellations on the chart can be located. (For more on the Summer Triangle click here).

If you look in the region of sky between, and slightly to the east of, Aquila and Cygnus you will spot the three smaller groups: Vulpecula (the Fox), Sagitta (the Arrow) and Delphinus (the Dolphin) (click here for more on Delphinus), while to the immediate southwest of Aquila is the faint but distinctive shape of Scutum (the Shield). All four of these constellations should be visible to the naked eye if the sky is dark and clear, although a pair of binoculars will help you to pick them out…

To the west of Lyra we see the conspicuous quadrilateral of stars marking the constellation of Hercules. Known as the ‘Keystone’, from it the rest of Hercules can be seen spreading away. Look immediately to the west of Hercules and you’ll spot the distinctive circlet of stars forming Corona Borealis (the Northern Crown), just beyond which is the distinctive shape of Bootes (the Herdsman).

If the sky is really dark and clear, you should be able to trace the winding pattern of Serpens Caput (the ‘head’ of the Serpent) snaking down towards the south. If you follow the line of stars shown here you’ll arrive at Ophiuchus (the Serpent Holder) with, to the east of Ophiuchus, the smaller line of stars Serpens Cauda (the ‘tail’ of the Serpent). According to Greek mythology, Ophiuchus depicts Asclepius, the god of medicine and son of Apollo. He is holding the head of the serpent in his left hand and the tail in his right hand, thereby splitting the constellation Serpens into two parts.

To the southwest of Ophiuchus, and lying a little way above the southern horizon, we can see the brilliant red Antares, the leading star in Scorpius (the Scorpion). The name Antares means ‘rival of Mars’ from the fact that, when Mars (often referred to as the red planet) and Antares are in the same area of sky, the two objects rival each other for prominence.

So, if the evening is warm, and the skies are clear and moonless, why not take yourself outside and check out the summer star patterns? And if you’re an early riser, look out for the transit of Venus on 6th June. Good luck… and happy sky gazing!

 

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Hunting Orion in the Peak District http://www.walkmag.co.uk/news/hunting-orion-in-the-peak-district/ http://www.walkmag.co.uk/news/hunting-orion-in-the-peak-district/#comments Thu, 08 Mar 2012 10:04:58 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=19416

Following on from the Campaign to Protect Rural England’s successful star counts, people are being asked to help monitor the impact of light pollution by scouring the skies for Orion over the Peak District starting this weekend. The aim is to scout out the best, darkest locations for star-gazing in the Peak District National Park and its surrounding areas.

To take part, simply head out in the area after 8pm on a clear night between March 10-17 and look for the constellation of Orion, with its distinctive belt of three bright stars in a line, with a smaller three-star sword below (For more on Orion, check out Brian Jones’ astronomy column for walk). Once you’ve found him, count how many stars are visible within the constellation’s main rectangle.

“We held a similar exercise this time last year,” says Peak District Dark Skies Group spokesman John Tanner. “Results showed 80% of people in the national park were able to stargaze under excellent skies, compared to 50% of people outside the national park. The best results in the national park were recorded at Monyash in the White Peak, and Edale in the Dark Peak. Light pollution not only affects our enjoyment of the night sky, it wastes energy and has an negative impact on the wellbeing of people and wildlife. Unfortunately, light pollution is increasing, so we are encouraging people to switch off unnecessary lighting and focus lights only where needed, or future generations may never experience the wonder of a truly dark night sky.”

If you’re interested in taking part, visit www.peakdistrict.gov.uk/darkskies where you’ll find full instructions, downloadable star charts.

Image by Janne.

 

 

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Brian Jones: Spring skies http://www.walkmag.co.uk/blogs/brian-jones-spring-skies/ http://www.walkmag.co.uk/blogs/brian-jones-spring-skies/#comments Fri, 24 Feb 2012 08:39:33 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=18918

Meteors, or shooting stars, appear as rapidly-moving streaks of light seen against the background of stars and are caused by tiny particles of dust which wander close to our planet and fall prey to the Earth’s gravitational pull. Drawn down through our atmosphere at speeds of anything up to 45 miles (70km) per second they collide with air particles, the resulting friction causing them to burn up, leading to their appearance as shooting stars.

Although meteors can appear at any time, and from anywhere in the sky, numerous predictable peaks of meteoric activity occur throughout the year. The April Lyrids make their annual appearance between the 16th and 25th April, with maximum activity taking place during the early hours of the 22nd. The source of the Lyrids is Comet Thatcher, discovered in 1861 and found to orbit the Sun once every 415 years. As the Earth makes its annual passage through the orbital path of Comet Thatcher, particles of cometary debris are pulled in and disintegrate in our atmosphere, producing a visual display. As New Moon occurs on the 21st this year, there will be no moonlight around to drown out the light from the meteor shower, thereby presenting the would-be Lyrid observer with dark, and hopefully cloud-free, skies.

Because the particles associated with comets travel around the Sun in parallel paths, the meteors they produce will all appear to emerge from the same point in the sky, an effect similar to that seen with railway lines which are also parallel but which seem to merge in the distance. This point is known as the radiant and the meteor shower is usually named after the area of sky in which the radiant is located.

In the case of the Lyrids, the radiant lies in the constellation Lyra, quite close to the bright star Vega (for more on Lyra, click here to read my previous post on the constellation). Normally a summer constellation, Lyra can be seen a little way above the north-eastern horizon during April evenings and Vega, its brightest star, should be visible if there are no buildings or other obstructions in the way. If you spot a meteor, and want to verify whether you’ve seen a Lyrid, tracing its path back should take you a point in the sky close to Vega. If it doesn’t, then you will have seen what is termed a sporadic meteor which, unlike shower meteors, have no associated comet and can appear at any time and anywhere in the sky.

If you want to check out the April Lyrids you need to dress warmly. Position yourself on a reclining chair and look towards the north-eastern sky. You would normally be expected to see between 15 and 20 naked-eye Lyrid meteors per hour, although the Lyrids can occasionally surprise observers by delivering a dramatic increase in the hourly meteor rate. Notable examples are the display of 1922, which produced up to 100 meteors per hour for a short time, whilst that of 1982 was almost as impressive, with up to 90 meteors per hour being seen. However, both these pale into insignificance when compared to the Lyrid display of 1803 during which observers in the eastern United States witnessed up to 700 meteors per hour! Records of the Lyrid meteor shower extend as far back as 687BC and, although normally only moderately active, this shower is well worth keeping an eye on as these sometimes-dramatic increases in activity are unpredictable.

Other sights worth checking out in April include the planet Venus, which is easily spotted throughout the month in the western sky late in the evening before setting. Of particular interest is the fact that, on the evenings of third and fourth of April, Venus will be located on the southern edge of the Pleiades open star cluster in Taurus and will be an impressive sight in binoculars. The planet will be in the same binocular field of view as the Pleiades from the first to the fifth, and checking it out over consecutive evenings will reveal the motion of Venus against the field of background stars.

Other planets on view this month are Mars and Saturn which will be covered more extensively in the next blog. Mars is located a little to the east of the bright star Regulus in Leo (click here to read more on Leo) whilst Saturn can be spotted in the south-east a little to the north of the bright star Spica in Virgo (click here to read more on Virgo).

Maybe you could invite fellow ramblers around for a few glasses of wine and supper, and then finish the evening off, albeit a late one, by watching out for the Lyrids! Happy meteor-hunting!

 

 
Time lapse image of a Lyrid meteor by fruitbit.

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Brian Jones: Winter stars http://www.walkmag.co.uk/blogs/brian-jones-winter/ http://www.walkmag.co.uk/blogs/brian-jones-winter/#comments Wed, 25 Jan 2012 08:39:33 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=18288 CAMELOPARDALIS: THE GIRAFFE WHICH ROAMS A BARREN AREA OF SKY

This month we are checking out one of the faintest of the constellations, primarily to offer you the challenge of picking out this obscure group which graces the skies in the region of the Pole Star. During winter evenings, the faint constellation Camelopardalis can be spotted a little to the north of the overhead point. To find it, you first of all need to find Polaris, the Pole Star, shown here on a finder chart which depicts the Plough and Ursa Minor as seen in the northern sky during January evenings. Following a line from Merak, through Dubhe, as shown on the main chart, will lead you to the Pole Star. The stars forming the giraffe can be seen stretching away from the region of Polaris roughly towards the overhead point, and you should be able to pick out the constellation reasonably easily providing the sky is dark, clear and free of moonlight.

The constellation of Camelopardalis is long and straggling and indeed resembles the character it depicts, lying in an area of sky containing no bright stars and which consequently was left blank by Greek astronomers. Camelopardalis was originally devised by the Dutch astronomer Petrus Plancius in 1613 and was first depicted graphically in 1624 by the German astronomer Jacob Bartsch who included it in his star chart published that year. The constellation is thought to represent the animal which carried Rebecca on her journey to Canaan and her marriage to Isaac.

Click to enlarge

The brightest star in Camelopardalis is Beta, a yellowish supergiant around a hundred times the size of our Sun and which shines from a distance of well over 1,000 light years. Slightly fainter is the somewhat-unromantically named CS, a bluish star which lies at a distance of around 4,000 light years. Considerably closer than these two is Gamma, a star whose light set off towards us a little over 300 years ago.

Of particular interest in Camelopardalis is Kemble’s Cascade. Named after the Franciscan Friar and amateur astronomer Lucian J. Kemble, this slightly-meandering chain of unrelated stars is a pretty sight when viewed through binoculars. Also known as the Waterfall, it stretches for a distance equal to around five times the diameter of a full Moon. To locate it, start from a point roughly a third of the way from the star BE towards CS.  Kemble’s Cascade can then be seen as a meandering line of stars roughly in the direction of the star 7, one of the southernmost stars in Camelopardalis. If the sky is fairly dark and moonless, and you sweep the area with binoculars, you should easily pick out this pretty collection of stars.

Although not the topic of mythology that some constellations are, why not take a trip outdoors to check out the stars which form this faint constellation, and give yourself a pat on the back if you manage to identify its major stars! Happy stargazing!

Click here for more astronomy tips from Brian Jones.

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Dream views of a winter wonderland http://www.walkmag.co.uk/news/dream-views-exhibition/ http://www.walkmag.co.uk/news/dream-views-exhibition/#comments Wed, 04 Jan 2012 10:18:29 +0000 Chris Hatherill http://www.walkmag.co.uk/?p=18138 The New Forest National Park’s popular ‘Dream View’ exhibition is on show over the holidays at the Moors Valley Country Park’s Visitor Centre, which will also host a special stargazing evening on the 20th of January. The photography exhibition celebrates what people enjoy most about the New Forest, with members of the public invited to submit their favourite photos of the area and the elements that make it so special – with ponies being a particularly popular subject.

Under 16s winner Chloe Hinton says of her winning image, entitled Sunrise Horses, ”the frosty background represents the cold winter we had last year, however the horses look happy and content and don’t seem to mind. The background behind is typical New Forest and I think this is a perfect ‘dream view’. The pony is probably the most common New Forest animal that roams freely.”

This year, to mark the Olympic Games coming to London, the 2012 competition has a special Olympic theme with the categories of gold, silver and bronze – and a wider creative remit with photographs, paintings, sculpturse, stories or poems of the New Forest welcome – so think golden sunsets, sliver light on water, bronze autumn leaves.

For more information on how to enter, visit www.newforestnpa.gov.uk/news/olympics-competition

The exhibition at Moors Valley is on now until 15 January 2011. For more information, and details of their Stargazing Live event in January, visit www.moors-valley.co.uk

 


 

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