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Scotland’s Sky in January, 2016

Quadrantids bring New Year fireworks on the 4th

The maps show the sky at 21:00 GMT on the 1st, 20:00 on the 16th and 19:00 on the 31st. (Click on map to enlarge)

The maps show the sky at 21:00 GMT on the 1st, 20:00 on the 16th and 19:00 on the 31st. (Click on map to enlarge)

If one of our resolutions for the New Year is to get to grips with the sky at night, then we could hardly do better than start with our January evenings. The unmistakable constellation of Orion the Hunter rises in the east at nightfall and is the centrepiece of a star-strewn region in the south-south-east by our star map times. On the other hand, most of the brighter planets, and what may be our brightest comet of 2016, are best seen in the morning sky.

Just as last month brought the Geminids as the best meteor shower of 2015, so the imminent Quadrantids shower may provide our best display of 2016. Lasting from today until the 6th, but with most of its activity in the hours before dawn on the 4th, its medium speed meteors are seen in all parts of the sky but diverge from a radiant point below and left of the Plough’s handle. The Plough itself lies in the north at nightfall and climbs through the north-east and east to lie overhead before dawn.

Most of the constellation figures show little relation to the things, persons or animals they represent. Orion is a striking exception, for he has conspicuous stars at his shoulders and knees and an iconic line of three stars to define the belt around his waist. Admittedly, his head is marked only by a knot of fainter stars, although if we look carefully we can find an arc of other faint stars to represent the shield he holds in the face of the charging bull, Taurus. Another line hangs below his belt to form his sword.

Use binoculars or a telescope to inspect the sword and it is easy to spot the Orion Nebula, a cloud of gas and dust that lies some 1,350 light years away. This miasma of greens, reds and blues is a region where new stars are forming, together with their nascent planetary systems.

The line of Orion’s belt slants downwards to the brightest star Sirius in Canis Major, the larger of Orion’s two dogs. Extend the line the other way and we reach Taurus with its leading star Aldebaran in and the Pleiades star cluster. As Orion sinks towards our western horizon early on the morning of the 20th, Aldebaran is once again occulted by the Moon. As seen from Edinburgh, the star disappears behind the upper edge of the Moon just before 03:24.

It may be hard to believe, but the Earth is closest to the Sun for the year (147,100,176 km) when it reaches perihelion late tomorrow. Sunrise/sunset times for Edinburgh vary from 08:44/15:49 today to 08:10/16:42 on the 31st, while the Moon is at last quarter tomorrow, new on the 10th, at first quarter on the 16th and full on the 24th.

Jupiter rises at Edinburgh’s eastern horizon at 22:39 tonight and two hours earlier by the 31st. Now in south-eastern Leo and already twice as bright as Sirius, it brightens from magnitude -2.2 to -2.4 this month and reaches a so-called stationary point on the 8th when its easterly motion reverses to westerly. If you did get a telescope for Christmas, then enjoy the view of its fascinating cloud-banded disk which swells in diameter from 39 to 42 arcseconds. Jupiter stood near the Moon last night and the two are even closer on the 28th-29th.

Mars rises in the east-south-east by 02:15 and lies to the left of Spica in Virgo as they pass 25° high in the S before dawn tomorrow. The Moon is nearby on Sunday and even closer on 1 February, by which time Mars has travelled east-south-eastwards into Libra where it lies just above the double star Zubenelgenubi. Mars improves from magnitude 1.3 to 0.8 to overtake Spica in brightness, but is shows only a small 6 arcseconds disk through a telescope.

Venus continues as a brilliant morning star (magnitude -4.1 to -4.0) though its altitude in the south-east at sunrise sinks from 15° today to 8° by the 31st. It lies to the right of the waning Moon on the 7th when a telescope shows its disk to be 79% sunlit and 14 arcseconds wide. Venus is just 2° to the right of Saturn on that morning and within 7 arcminutes of Saturn on the 9th. At magnitude 0.5, Saturn is much the fainter of the two as it creeps eastwards in southern Ophiuchus.

Mercury has a few more days as a difficult evening star. It is bright at magnitude -0.2 tonight, but it hugs our south-western horizon at nightfall and sets less than 100 minutes after the Sun. As the month ends it is back in our morning twilight, a few degrees to the left of Venus.

Comet 2013 US10 Catalina has remained stubbornly below naked eye brightness in our morning sky, though photographs reveal a striking divergence between its tails of dust and ionized gas, the latter being torn and billowed by the solar wind.

Following perihelion 123 million km from the Sun in mid-November, the comet is closest to Earth (108 million km) on the 17th. Likely to appear as a small greenish fuzzy blob through binoculars, it moves from less than 0.5° west of the conspicuous star Arcturus in Bootes this morning to lie 1.2° east of Alkaid, the star at the end of the Plough’s handle, before dawn on the 15th. It is currently around the sixth magnitude but may be a magnitude dimmer by the month’s end as it sweeps within 9° of Polaris and recedes on a trajectory that will never bring it back towards the Sun.

Alan Pickup

This is a slightly-revised version of Alan’s article published in The Scotsman on January 2nd 2016, with thanks to the newspaper for permission to republish here.  Journal Editor’s apologies for the lateness of the article appearing here.
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Scotland’s Sky in December, 2015

Get ready for a memorable meteor display

The maps show the sky at 21:00 GMT on the 1st, 20:00 on the 16th and 19:00 on the 31st. (Click on map to englarge)

The maps show the sky at 21:00 GMT on the 1st, 20:00 on the 16th and 19:00 on the 31st. (Click on map to englarge)

Experience tells us that the coldest night of the winter is unlikely to occur during December, but the month does bring our longest ones as the Sun dips to its farthest south at the winter solstice, due this year at 04:48 GMT on the 22nd.

Those long nights begin with Pegasus nearing the meridian but, by our star map times, its famous Square is in the south-west and our eastern sky has been claimed by the sparkling constellations of winter. Orion is unmistakable, his three Belt stars aligned almost vertically and pointing up to Aldebaran in Taurus and on to the Pleiades cluster.

There is another occultation of Aldebaran by the Moon on the 23rd with the star blinking out at the Moon’s limb just before 18:18 as viewed from Edinburgh, and reappearing by 19:15. The Moon’s glare means that we will probably need a telescope to view the event.

Sunrise/sunset times for Edinburgh vary from 08:18/15:44 on the 1st, to 08:42/15:40 on the 22nd and 08:44/15:47 on the 31st. The Moon’s last quarter on the 3rd is followed by new on the 11th, first quarter on the 18th and full on the 25th.

Our evening sky remains devoid of bright planets at present, but the return of the annual Geminids meteor shower is ample compensation. Now regarded as our best meteor display, this is active from the 8th to the 17th with its peak predicted for about 13:00 on the 14th with meteor rates of perhaps 120 per hour for an observer under an ideal dark sky. This is, of course, during our daylight but, unlike some other showers, meteor activity remains high for more than 24 hours and the nights of 13th/14th and 14th/15th could both be memorable. Just be careful to wrap up well to get your fill of long, bright, medium-slow meteors.

The radiant, the point in the sky from which the meteors appear to diverge, is plotted close to the star Castor in Gemini on the eastern side of our North map. Gemini lies north and east of Orion and as Orion marches across our southern sky so the radiant climbs to pass high in the south at 02:00. Remember that the meteors are visible in all parts of the sky, not just near Gemini – it is their streaks that point back to the radiant.

As Orion crosses our meridian some four hours after our map times, so the first bright planet of the night rises in the east. Jupiter brightens further from magnitude -2.0 to -2.2 as it creeps 2° or four Moon-breadths east-south-eastwards in south-eastern Leo, some 20° below and left of the star Regulus.

As the most conspicuous object in the middle of our southern sky before dawn, Jupiter stands just above the Moon on the 4th and to the Moon’s left on the 31st. By the month’s end, it rises more than one hour before midnight and its interesting cloud-banded disk has swollen in diameter from 36 to 39 arcseconds as seen telescopically.

The night’s second naked-eye planet, Mars, lies 20° east-south-east (below-left) of Jupiter and just below the star Porrima in Virgo as the month begins. At magnitude 1.5, but improving to 1.3, it, too, tracks east-south-eastwards to pass 4° north of Spica on the 21st. Look for it close to the waning Moon before dawn on the 6th but don’t expect your telescope to show much if any detail on its tiny 5 arcseconds disk.

The third planet is the brightest of all. Venus climbs above Edinburgh’s eastern horizon at 03:53 on the 1st and, at magnitude -4.2, may still be visible 25° high in the south-south-east at sunrise. It is then 4° north-east of Spica, but it speeds through Virgo and much of Libra so that, by the 31st, it rises in the south-east at 05:26 and is 15° high in the south at sunrise.

As Venus recedes, its gibbous disk shrinks from 17 to 14 arcseconds in diameter. Its motion takes it 2° above Zubenelgenubi in Libra on the 17th and to within a similar distance of the Graffias in Scorpius on the 31st. Venus is occulted for observers over much of N America as it is overtaken by the Moon next Monday.

Saturn, magnitude 0.5, emerges from the morning twilight to hover low in the south-east, below and to the left of Venus, during the final ten days of the year. On those same days, but in the evening, it might just be possible to spot Mercury as it shines at magnitude -0.5 some 5° high in the south-west only 30 minutes after sunset.

Comet 2013 US10 Catalina is likely to be a binocular object as it climbs into our south-eastern sky before dawn. Thought to be an asteroid when it was discovered in 2013, hence its odd name, it was closest to the Sun (123 million km) on November 15 and is due to pass closest to the Earth (108 million km) on January 17. There has been speculation that it might become a naked eye object of the fourth magnitude or better.

However, having spent weeks hidden in the Sun’s glare, it was a disappointing sixth magnitude object when it was recovered a couple of weeks ago. I fear it may not get much better than this, though the fact that it has two, or even three, tails will make for some interesting photographs. From 11° below-left of Venus as the month begins, it tracks almost due northwards to stand only 4° to the right of Venus next Monday (with the Moon nearby) and lie a mere 2° south of the bright star Arcturus in Bootes by the 31st.

Alan Pickup

This is a slightly-revised version of Alan’s article published in The Scotsman on December 1st 2015, with thanks to the newspaper for permission to republish here.

Scotland’s Sky in October, 2015

Morning sky holds planetary bonanza

The maps show the sky at 23:00 BST on the 1st, 22:00 BST (21:00 GMT) on the 16th and at 20:00 GMT on the 31st. Summer time ends at 02:00 BST on the 25th when clocks are set back one hour to 01:00 GMT. (Click on map to englarge)

The maps show the sky at 23:00 BST on the 1st, 22:00 BST (21:00 GMT) on the 16th and at 20:00 GMT on the 31st. Summer time ends at 02:00 BST on the 25th when clocks are set back one hour to 01:00 GMT. (Click on map to englarge)

We are well into autumn, yet our sky at nightfall looks much as it did two months ago. The Summer Triangle (Vega, Deneb and Altair) stands high near the meridian and we still have Saturn very low down in the south-west. Shining at magnitude 0.6, and below the young Moon on the 16th, it is tracking eastwards from Libra into Scorpius but we are likely to lose it to the evening twilight later in October.

The hour by hour westwards progress of the stars in the south carries the Triangle into the west and Pegasus to the meridian by our star map times. Taurus in the east and Gemini, just rising, herald the coming of our glorious winter constellations whose leader, Orion, rises another two hours later and is resplendent in the southern sky before dawn. The eastern morning sky also boasts a trio, soon to be a quartet, of planets, including Venus and Jupiter which enjoy a spectacular conjunction on the 26th.

The southern quarter of our sky at our map times is relatively underwhelming. The Square of Pegasus is large, empty and far from striking though one obvious adjoining constellation is Andromeda which extends eastwards, to the left, from the Square’s top-left corner. Indeed, that star, Alpheratz, is now assigned to Andromeda after years with a bigamous classification as both Alpha Andromedae and Delta Pegasi.

Andromeda’s famous galaxy, M31, lies 2.5 million light years away yet is visible as an oval smudge of light to the unaided eye, and is easy to spot using binoculars. Stand by for its collision with our own Milky Way galaxy in another four billion years or so.

Pisces sprawls to the south and east of the Square but is so dim that I often omit it from our chart. The planet Uranus reaches opposition in Pisces on the 12th when it shines at magnitude 5.7 from 2,840 million km. A better chart and binoculars should show it easily, while it is bright enough to be a naked-eye object in a good dark sky.

To its south and west, and scudding westwards below the star Iota in Cetus as shown by the arrow on our chart, is the asteroid Vesta. This stood 214 million km away at opposition on September 28 and dims from magnitude 6.2 to 6.8 during October. A more challenging binocular target is the farthest planet, Neptune, which is magnitude 7.8 and stands 4,377 million km away in Aquarius at mid-month.

The Sun sinks 11° southwards during October as sunrise/sunset times for Edinburgh change from 07:15/18:49 BST (06:15/17:49 GMT) on the 1st to 07:16/16:35 GMT on the 31st after our clocks reset to GMT on the 25th. The Moon is at last quarter on the 4th, new on the 13th, at first quarter on the 20th and full on the 27th. The evening of the 29th sees the waning gibbous Moon occult Aldebaran in Taurus. As seen from Edinburgh, the star winks out at the Moon’s bright limb at 21:57 GMT and reappears at its dark edge at 22:49 – use a telescope.

There is no prize for spotting the brightest planet Venus before dawn, though perhaps we deserve one for observing at such unsocial hours. Venus rises to the north of east as seen from Edinburgh at 03:09 BST on the 1st and 02:36 GMT on the 31st, climbing 33° into the south-east by sunrise. Fading a little from magnitude -4.5 to -4.3, it recedes from 76 million to 110 million km and its dazzling disk shrinks telescopically from 33 to 23 arcseconds in diameter as its phase evolves from 35% to 54% sunlit.

Venus lies above and to the right of Leo’s leading star Regulus at present but slides eastwards to pass 2.6° south of the star on the 9th as it draws closer to the second outstanding morning planet, Jupiter. The latter is barely a tenth as bright as Venus, but remains brighter than the brightest star as it improves from magnitude -1.7 to -1.8 and slips 6° eastwards in southern Leo. Jupiter’s cloud-banded disk appears 32 arcseconds wide in mid-October.

Catch the waning Moon above and to the right of Venus on the 8th, below Venus on the 9th and below Jupiter on the 10th.

Set your alarm early for the morning of the 26th when Venus lies just 1° or two Moon-widths below-right of Jupiter in the year’s most spectacular planetary conjunction. True, the two where even closer together on July 1, but that conjunction occurred with them low in our bright evening twilight while this month’s rendezvous sees than high in the east before dawn. Indeed, it coincides with Venus reaching its furthest angular distance of 46° west of the Sun in the sky.

Much fainter is Mars which moves from 4° below-left of Regulus on the 1st to pass only 0.4° north of Jupiter on the 17th. At magnitude 1.8 to 1.7, it is fainter than Regulus while its orange-hued disk is only 4 arcseconds wide. On the morning of the 31st, Mars sits 1.5° to the left of Venus which, by then, lies 4.5° below-left of Jupiter.

At the beginning of its best morning apparition of 2015, Mercury emerges from the dawn twilight next week to lie low in the east as our fourth predawn planet. Seen from Edinburgh, it rises 90 or more minutes before the Sun from the 10th to the 26th, brightening during that period from magnitude 0.6 to -0.9 and climbing to be 7° to 10° high forty minutes before sunrise. Glimpse it 2.6° below-left of the very slim earthlit Moon on the 11th.

Alan Pickup

This is a slightly-revised version of Alan’s article published in The Scotsman on October 1st 2015, with thanks to the newspaper for permission to republish here.

Scotland’s Sky in September, 2015

Total eclipse of the harvest supermoon on the 28th

The maps show the sky at 23:00 BST on the 1st, 22:00 on the 16th and 21.00 on the 30th. (Click on map to englarge)

The maps show the sky at 23:00 BST on the 1st, 22:00 on the 16th and 21.00 on the 30th. (Click on map to englarge)

There is no shortage of stellar interest in our September evening sky but anyone willing and able to observe later in the night may see the largest full moon of the year turn dull and red as it is totally eclipsed on the morning of the 28th. There is also a nice grouping of planets in the east before dawn.

Our chart depicts the sky in our late evening at present and shows the star Deneb in Cygnus almost at the zenith as the Summer Triangle it forms with Vega and Altair begins to topple westwards. The Square of Pegasus is climbing in the south-east in a rather sparsely populated region of the sky.

The Pleiades in Taurus glimmer low in the east-north-east as they begin their climb to the high meridian by dawn. They stand above the Moon on the Friday night of the 5th/6th as the Moon draws closer to Aldebaran, the leading star of Taurus, eventually to occult the star during the morning twilight. As seen from Edinburgh the star winks out as it disappears behind the sunlit eastern edge of the Moon at 05:51 BST on Saturday, 6th.

Our sole bright evening planet, Saturn, hovers only 10° above Edinburgh’s south-western horizon as darkness falls and sinks a little lower each evening as it creeps eastwards against the stars of eastern Libra. Telescopically, its disk appears 16 arcseconds broad while the rings are 37 arcseconds across with their north face inclined at 24°, but it is past its best as a target and, since it sets 30 minutes before our map times, we need to be quick to catch it. Look for it to the left of the young Moon on the 18th.

The Sun slips southwards over the celestial equator at 09:21 BST on the 23rd, marking the autumnal equinox in our northern hemisphere. Meanwhile, sunrise/sunset times for Edinburgh change from 06:16/20:08 BST on the 1st to 07:13/18:52 to the 30th as the duration of nautical twilight at dawn and dusk shrinks from 89 to 80 minutes.

The Moon is at last quarter on the 5th and new on the 13th when a partial solar eclipse is visible from southern Africa and Antarctica. Following first quarter on the 21st, the full moon on the 28th is a much more intriguing event because not only is it totally eclipsed, but it coincides with the Moon’s closest approach to the Earth (at perigee) in the whole of 2015. As a result, the Moon appears 7% wider than it does on average and, while the enlargement is not startlingly obvious to the casual observer, it has led to near-perigee full moons being called supermoons.

As the full moon closest to the equinox, this is also the harvest moon, a title that comes from the fact that, for several nights in a row, the bright Moon hangs low in our eastern sky as the night begins and extends the period by which the harvest may be gathered. The illusion that makes the Moon appear larger than usual when it stands low in the sky is also pronounced around this time and can only be enhanced by the supermoon circumstance.

The eclipse on the morning of the 28th, though, begins at 01:12 BST with the Moon well up in our southern sky, in the constellation Pisces and below the Square of Pegasus. The Moon meets the outer edge of the Earth’s penumbral shadow at that time, but little darkening may be noticed for another 30 minutes or more.

The dark shadow of the umbra beings to invade the lunar disk at 02:07, while from 03:11 until 04:23 the Moon is totally eclipsed as it crosses the southern part of the umbra. Here the Moon is only illuminated, usually with a reddish hue, by light scattered around the edge of the Earth. Varying atmospheric conditions, clouds and volcanic dust, on our home world mean that the appearance and brightness of the eclipsed Moon is always of interest. The Moon leaves the umbra behind at 05:27 and stands only 7° above Edinburgh’s western horizon when it exits the last of the penumbra at 06:23.

Venus, already a spectacular morning star, rises at Edinburgh’s east-north-eastern horizon 100 minutes before the Sun on the 1st and more than four hours before sunrise at the month’s end. Improving from magnitude -4.4 to -4.5, it shows a slender but dazzling crescent through binoculars though it shrinks in diameter from 51 to 43 arcseconds as it recedes from 48 million to 76 million km.

The giant planet Jupiter lags some 20° below-left of Venus and emerges from the Sun’s far side by mid-month to shine at magnitude -1.7, just brighter than Sirius which is low in the south-east at the time.

Our third morning planet, Mars, is much fainter at magnitude 1.8 and stands 9° above-left of Venus on the 1st. Also still on the far side of its orbit, it slips down and to the left in the direction of Jupiter and passes 0.8° north of Leo’s leading star Regulus on the 24th. The blue-white of Regulus outshines the orange tinted Mars and the contrasting pair make an interesting sight roughly half-way between Venus and Jupiter for a few mornings around that day.

The little innermost planet, Mercury, stands furthest east of the Sun (27°) on the 4th but is much too low in our western evening twilight to be seen this month. After sweeping around the Sun’s near side on the 30th, it is due to make its best appearance of the year as a morning star in October.

Alan Pickup

This is a slightly-revised version of Alan’s article published in The Scotsman on September 1st 2015, with thanks to the newspaper for permission to republish here.