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Popular Astronomy Magazine - January-February 2018
See what's in the January-February 2018 edition of 'Popular Astronomy' magazine. Click the cover to find out.

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Fri, 05 Jan 2018


Early morning spectacular


Jupiter and Mars on the early morning of 6 January 2018, over Abbot Hall, Kendal, Cumbria. Photo by Stuart Atkinson

Stuart Atkinson writes:

If you're up early over the next few mornings you'll be able to see a "close encounter of the planetary kind" before sunrise. Two planets, Jupiter and Mars, are currently close together (visually, not physically; they just both happen to lie in that direction as seen from here on Earth) in the south-eastern part of the sky, and over the next week or so will get closer and closer each morning until they appear to pass and swap places.

This is something you'll be able to see with just your naked eye – you won't need a telescope or even a pair of binoculars, although if you have either of those they will enhance your view of it. Both Jupiter and Mars look just like stars in the sky, more than bright enough to be seen without magnification, and if you go out at around half past five/six o'clock at the moment and look to the south-east your eye is really drawn to them. Of the two, Jupiter is by far the brighter, and shines with a blue-white colour. In contrast, Mars is more orange in colour and quite a lot fainter.

To start with Jupiter is to the lower left of Mars, and there's quite a gap between them, but as the days pass the two planets will appear to move together until there's less than the width of the Moon between them on the morning of the 7th of January (see graphic below). Then they will swap places and Jupiter will be to the upper right of Mars.

If you have a pair of binoculars, or a small telescope, they will make the planets look brighter and enhance their colours, but you won't need them to enjoy this "planetary fly-by".

Although close encounters (or "conjunctions") like this aren't scientifically useful, they're really just interesting and attractive events to look at, and photograph if you want to, but again there's no need to. It's fine to just get up early, find somewhere with a good view to the south-east, and look!


Conjunction

Above: The movement of Mars (M) and Jupiter (J) during the first few days of January 2018. The star to the right of the pair is Alpha Librae, Zubenalgenubi

comparison
Comparison of the separation of the planets compared with the diameter of the Moon. Note, however, that the Moon will be some distance away on 7 January, and on 11 January, when it is just above the pair, the two planets will have separated. Graphics by Stuart Atkinson and Paul Sutherland.

 

Added by: Robin Scagell