Jupiter at its conspicuous best as Comet Lovejoy recedes
The prize for venturing outside after nightfall in February is a view of our most stunning evening sky of the year. Venus, now closing in on Mars, blazes low in the west-south-west as the twilight dwindles while the conspicuous planet Jupiter is climbing in the east and the glorious shape of Orion is unmistakable in the south-east.
By our star map times, Orion has progressed into the south-south-west and it is Jupiter that dominates in the south-east. The line of Orion’s Belt slants towards Sirius which twinkles furiously on the meridian and westwards towards Aldebaran and on to the Pleiades in Taurus. Extend it still further, and across onto the western side of our northern map, to locate the area where we now find Comet Lovejoy.
The comet has been an easy binocular object during January, appearing as a fuzzy ball of light climbing to the west of Orion and below the Pleiades. Indeed, it was visible to the naked eye in a dark sky while photographs brought out its long tail with several fast-changing spokes, kinks and knots and the striking green hue of its head, due to fluorescence from cyanogen and diatomic carbon. It peaked near magnitude 3.8 after passing closest to the Earth on 7 January and reaches its closest point to the Sun, perihelion, on 30 January.
Our north map shows it approaching the star Almach, the upper (eastern) bright star of Andromeda, and it passes less than 0.7° above it on the night of Wednesday, 4 February. In fact, we will find the comet and the star within the same binocular field until the 12th or so. Now receding and fading, it is closer to magnitude five at present and may be magnitude 6.5 by the month’s end as it heads towards the familiar W-shaped pattern of Cassiopeia.
Jupiter stands to the right of Leo’s Sickle and near the full Moon on Tuesday, 3 February as it edges westwards from Leo into Cancer. It reaches opposition in Cancer on the 6th when it stands opposite the Sun so that it rises in the east-north-east at sunset, is highest in the south around midnight and sets in the west-north-west at dawn. It is then at its closest (650 million km) and brightest (magnitude -2.6), and shows a 45 arcseconds disk through a telescope.
Its four main moons are visible through binoculars, unless, that is, they are in transit across the disk or hidden beyond it. With their orbits still edge on to us and to the Sun, they also eclipse each other occasionally.
The obvious surface features on Jupiter are the bands of dark and light clouds running parallel to its equator, but peppering these are streaks and spots that drift across the disk to betray the planet’s rotation in just under ten hours. Since it is observable throughout our long night, we might inspect its entire meteorology in a single session if we had the dedication and enough cups of coffee.
February sees the Sun climbs 9.5° northwards in the sky as the sunrise/sunset times for Edinburgh change from 08:08/16:45 on the 1st to 07:07/17:44 on the 28th. The duration of nautical twilight at dawn and dusk shrinks from 86 to 80 minutes. The Moon is full on the 3rd, at last quarter on the 12th, new on the 18th and at first quarter on the 25th as it passes just above Aldebaran.
Venus is now established as an brilliant evening star of magnitude -3.9, its altitude above Edinburgh’s south-western horizon at sunset increasing from 16° to 23° during February so that by the month’s end it is visible for more than three hours after sunset. Viewed telescopically, its dazzling and almost-full gibbous disk swells from 11 to 12 arcseconds in diameter.
Mars lies 10° above and to the left of Venus on the 1st, but is more than 100 times fainter at magnitude 1.2 and distinctly reddish in appearance. It is also a good deal smaller at 4 arcseconds and we will struggle to glimpse any of its surface detail. Both planets are more distant than the Sun at present, but while Venus is sliding closer to the Earth in its orbit, we are leaving Mars behind as it slips towards the Sun’s far side.
The two are also drawing closer together in our sky so that Venus lies 0.8° below Mars on the 20th with the slender young earthlit Moon 4° away, below and to their right. Venus lies only 0.5° (one Moon-breadth) below-left of Mars on the 21st when their distances from the Earth are 212 million and 330 million km respectively and they lie 10° below-right of the Moon. By the 28th, Venus stands 3° above-left of Mars.
Mercury remains hidden in our pre-dawn twilight but Saturn is a morning planet in Scorpius. Rising in the east-south-east at about 03:35 on the 1st and 01:55 on the 28th, it climbs almost 15° high into the south-south-east to south before dawn. As the brightest object low down in that part of the sky, it shines at magnitude 0.5 and surpasses the red supergiant Antares 9° below and to its left.
Saturn is tracking slowly eastwards but is at present just 1° north of the star Graffias which appears double through a small telescope but really has many stellar components. The planet lies 4° to the right of the waning Moon on the morning of the 13th when a telescope shows its disk to be 16 arcseconds wide, while its rings span 37 arcseconds and have their northern face tipped 25° towards us.
This is a slightly-revised version of Alan’s article published in The Scotsman on January 31st 2015, with thanks to the newspaper for permission to republish here.
Comet Lovejoy heralds an exciting year in astronomy
The coming year promises to be an exciting one in astronomy and space research. NASA’s New Horizons mission is due to make the first flyby visit to Pluto in July while Comet Churyumov–Gerasimenko is nearest the Sun a month later, hopefully with Europe’s Rosetta probe still alongside and in prime position to observe the comet in full flow. Whether we hear again from the Philae lander remains to be seen, but its controllers are hopeful that it may come back to life in the spring.
Closer to home, the highlight is surely the solar eclipse on the morning of 20 March. This is total for the Faroe Islands and Svalbard while from Scotland the Moon hides all but a thin sliver around the Sun’s lower limb. From Edinburgh 94% of the Sun is obscured but for observers in Kirkwall, Lerwick and Stornoway this jumps to 97%.
January should be interesting in its own right. Not only are all the planets on view, but the constellations centred on Orion dominate our evening hours and we have the prospect that Comet Lovejoy may be a naked-eye object as it climbs to the right of Orion.
The year begins with the Quadrantids meteor shower which is active from the 1st to the 6th but reaches a rather sharp peak at around midnight on the 3rd/4th when as many as 80 medium-speed meteors per hour might be seen under ideal conditions from a dark location. Sadly, the Moon is full on the 5th so all but the brighter meteors will be swamped in the moonlight this year. Quadrantids appear in all parts of the sky but their paths trace back to a radiant point that is plotted low in the north at our star map times. Later in the night the radiant follows the Plough as it climbs through our north-eastern sky.
You may find it surprisingly that the Earth is at perihelion, our closest to the Sun, at 06:36 on the 4th. The centre of our planet then lies 147,096,204 km from the Sun, 5 million km closer than it does at aphelion on 6 July. Sunrise/sunset for Edinburgh change from 08:44/15:49 on the 1st to 08:10/16:43 on the 31st as the duration of nautical twilight at each dawn and dusk shrinks from 96 to 85 minutes. That full moon on the 5th is followed by last quarter on the 13th, new moon on the 20th and first quarter on the 27th.
As the Moon climbs in the east on the evening of the 1st, it stands below the Pleiades and above-right of Aldebaran, the eye of Taurus. By 19:00 the whole of Orion is unmistakable in the east-south-east, moving into the south-south-east by our map times as the Pleiades glimmer on the meridian.
Our chart traces the path of Comet Lovejoy as it climbs from Lepus the Hare, at Orion’s feet, through Eridanus the River and Taurus as it approaches the star Almach in Andromeda as the month ends. Discovered in August by the Australian amateur astronomer Terry Lovejoy, the comet has brightened more than most people expected and reached the threshold of naked-eye visibility, the sixth magnitude, in mid-December.
During January I expect it to shine at around the 4th or 5th magnitude, fainter than the stars on our chart but perhaps similar in brightness to the Orion Nebula. As such, it should be visible easily through binoculars as a hazy smudge, probably smaller than the Moon and with brighter core around its nucleus. Indeed, it should be a naked-eye object in a dark sky once the current moonlight has subsided. Photographs show a greenish hue and a narrow striated tail more than 5° long pointing up and to the left, away from the Sun.
Comet Lovejoy takes about 13,500 years to orbit the Sun and reaches perihelion on 30 January at a distance of 193 million km. It comes closest to the Earth, 70 million km, on the 7th.
Jupiter remains our pre-eminent planet as it rises in the east-north-east some 90 minutes before our map times. Blazing at magnitude -2.5 to -2.6, it is now creeping westwards to the west (right) of the Sickle of Leo and crosses the meridian in the early hours. A telescope shows it to be 44 arcseconds wide when it stands above the Moon on the morning of the 8th.
Venus is a brilliant magnitude -3.9 evening star very low in the south-west as the night begins. It sets for Edinburgh at 17:07 on the 1st and at 18:58 by the 31st. Use it (and binoculars) to locate Mercury which shines at magnitude -0.8 as it moves from 3° below-right of Venus on the 1st to lie less than 0.7° to the right of Venus on the 11th. It then tracks to the right of Venus and lies 7° away by the 22nd when it is a difficult magnitude 0.9 object in the twilight. On that evening, the thin earthlit Moon lies 9° above Venus and 7° to the right of the orange-hued planet Mars (magnitude 1.2) which otherwise remains the brightest object low in the south-west at nightfall.
The other naked-eye planet, Saturn, rises in the south-east at about 05:20 on the 1st and almost two hours earlier by the month’s end, becoming the brightest object low in the south-south-east to south before dawn. This month it tracks eastwards from Libra to pass 1° north of the star Graffias in Scorpius. Look for Saturn 2.6° below-left of the waning Moon on the 16th when a telescope shows its globe to be 16 arcseconds wide within rings that span 36 arcseconds and have their north face tipped 25° towards the Earth.