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Mon, 25 Jul 2016

Planets in the twilight

Jupiter shines in the west after sunset

Three bright planets are attracting attention in the twilight sky. Over to the west, and setting soon after the Sun, is Jupiter, shortly to disappear behind the Sun for a few months. But with us for a month or two yet are Saturn and Mars, to the south, shining brightly but quite low down above the rooftops. (Or treetops, whichever you have.)

Saturn (left) and Mars in the south. Click to enlarge

Mars is the one on the right, and is lower down than Saturn. It's also much more obviously reddish in colour – maybe not blood red, as some fanciful descriptions suggest, but definitely on the ruddy side. Right now we are moving away from Mars so it's getting smaller, but it won't be as close again until May 2018 so if you have a telescope, take a look now. Chances are you won't see much because of its low altitude, but if you get good, steady conditions you should see its disc, currently about 13 arc seconds across, and maybe a dark marking or two. 

If you read something on the web about it being as big as the full Moon this August, take a look at our debunking page to find out why this old chestnut comes around every August!

Saturn is to the left of Mars, as seen from the northern hemisphere, and is a bit higher in the sky. This makes it a better bet for observing, and if you want to see its famous rings you can still see them with any telescope magnifying about 40 times or more. 

Right below Saturn and a bit fainter is the bright star Antares. It is a red giant star, and its name means 'Rival of Mars' because of its reddish colour. Take a look and compare the two. Throughout August, Mars draws closer to Saturn and by the end of August the two rivals are close in the sky. 


Added by: Robin Scagell