Winter stars sparkle now the days are starting to lengthen
Their widely public is ed meeting behind them, Jupiter and Saturn are now sinking into our twilight at dusk to leave Mars as the only prominent plane tina sparkling winter’ s sky dominated by the unrivalled constellation of Orion the Hunter. We have only a short time to wait for one of the new year’s top three meteor showers, the Quadrantids.
The shower is expected to yield more than 80 meteors per hour for someone under an ideal dark sky. For us, sadly, the peak is rather narrow and expected during daylight on the 3rd.
However, respectable numbers should still be seen during next Saturday and Sunday nights and, despite the moonlight, particularly during the morning hours as the radiant point from which the meteors appear to diver ge climbs high in our eastern sky. This point is plotted on our north star map and lies in what is now northern Bootes, below and left of the Plough’s handle.
Mars stands high in the south-east at nightfall, moving into the south-west by our map times and onwards to the west-north-western horizon six hour later.
Like a bright non-twinkling orange-hued star, Mars halves again in brightness from magnitude - 0.2 to 0.5 in January as it tracks 15° eastwards from Pisces into Aries. En route it is passed by the Moon which is at first quarter when it stands 9° belowright of the planet on the 20th. On that evening, Mars stands 162 million km away, exactly 100 million km further than it was at its closest in October, and appears less than 9 arcseconds across telescopically. The three spacecraft on their way to Mars are due to arrive between the 11th and 18 th of February.
Betelgeuse, theredsu pergiants tar at the top-left shoulder of Orion, is usually outshone( as at present) by the contra sting blue supergiant Rig el at Orion’ s lower-right. Between them are the three stars of Orion’ s Belt named, from left to right, Al n it ak, Al nil am and Min
“Stories that Jupiter and Saturn formed a ‘Christmas Star’ akin to the Star of Bethlehem are, frankly, overblown and misleading”
t aka. Hanging below these, as I mentioned last month, is Orion’ s Sword with the glowing star-forming region of gas and dust we know as the Orion Nebula – best spotted through binoculars.
The line of the Belt slants down to Sirius, the brightest star in Earth’ s night sky, and upwards towards the orange giant Al de bar an in Taurus. The latter lies 65 light years (ly) away and is a foreground star between us and the V-formation Hyades star cluster, perhaps the most important cluster in the whole sky. At 153 ly, it is the closest and best studied star cluster, having played a vital role in calibrating the relationship between the colours and luminosities of stars while they are generating their energy by fusing hydrogen into helium in their cores. For all its scien - tific significance, the Hyades usually plays second-fiddle in popular culture to the bright er P lei ad es cluster, 12° away to the nor th-west – catch the Moon between the two on the 23 rd.
Following the winter solstice on 21 December, the Sun climbs 6° north wards d uring January causing Ed inburgh’ s days to length en by almost 90 minutes and sun
rise/ sunset times to change from 08:44/15:50 on the 1st to 08:09/16:44 on the 31st. The Moon is at last quarter on the 6th, new on the 13th, first quarter on the 20 th and full on the 28th.
It is just a coincidence that our winter solstice came on the same day as that rare close conjunction between the two largest planets, their closest visible convergence in almost 800 years. However, stories that Jupiter and Saturn formed a “Christmas Star” akin to the Star of Bethlehem are, frankly, overblown and misleading. Anyone expecting a wondrously bright spectacle was to be sorely disappointed since the combined brightness of the two was a barely perceptible 10 per cent greater than that of Jupiter alone, and Jupiter, in any case, is only half as bright as it was in our midnight sky just a few months ago.
We need a clear unobstructed south-western horizon to see Jupiter as it stands 8° high for Edinburgh 30 minutes after sunset tomorrow, and probably bi no culars to glimpse Saturn ,1.2° below and to its right. Jupiter shine sat magnitude -2.0, bright er than Sirius, while
Saturn is a tenth as bright at magnitude 0.6.
They separate as they slide lower into the twilight, so that the equivalent altitude of Jupiter on the 9th is down to 5° and they area further degree apart. The smallest and innermost planet, Mercury, joins them to shine at magnitude -0.9 when it lies 1.8° below Saturn on the 9 th and 1.4° below-left of Jupiter on the 11th. By the 14th, with Jupiter down to 3°, Mercury is 4° above -left of Jupiter and the same distance to the right of the thin sliver of the young Moon, only 3% sunlit. Saturn reaches conjunction beyond the Sun on the 24th followed by Jupiter five days later.
Mercury remains an evening object as it moves to lie furthest east of the Sun (19°) on the 24th. Between the 19th and 31st, it stands more than 7° high in the south-west 30 minutes after sunset and, horizon permitting, should be easy to spot through binoculars as it dims from magnitude - 0.8 and 1.0.
Just as two bright planets slide into our evening twilight, so the most brilliant of all, magnitude -3.9 Venus, is disappearing before dawn. Tomorrow, it rise sin the south-east 90 minutes before the Sun and stands 7° high at sunrise. By the 25th, though, these numbers diminish to 32 minutes and 3° although it will be late in March before it reaches its so - called supe - rior conjunction on the Sun’s far side.