As nautical twilight starts at 7am GMT for the centre of the British Isles on 9 January, planets Venus and Saturn are separated by just 9¼ arcminutes — less than a third of the apparent diameter of the full Moon — very low to the southeast. They were at their closest (5 arcminutes) at 4am GMT, but below the UK horizon at that time. Both planets lie 6⅔ degrees to the upper left of star Antares, so all three will fit within the field of view of a 7×50 binocular. AN graphic by Ade Ashford.On Saturday, 9 January at 3:57am GMT, magnitude -4.0 Venus passes just 5 arcminutes — less than one tenth of a degree — north of magnitude +0.5 Saturn. While the instant of closest approach will be missed by observers in the extreme west of Europe as Venus and Saturn will still be below the horizon, by 7am GMT the ‘double-planet’ will be high enough to be glimpsed with the naked eye very low to the southeast from the UK.
By 7am GMT the gap between these two prominent planets will have widened to 9¼ arcminutes — still less than a third of the apparent diameter of the full Moon. Observers with motorised equatorial or GoTo mounts can track the rising pair in the same eyepiece field at magnifications up to 175x until Saturn fades into daylight.
As always, whenever observing in daylight please take extreme care lest the Sun enters the field of view of your telescope or finder with disastrous consequences for your eyesight or anyone else who accidentally looks at it.
Even casual observers cannot fail to notice dazzling Venus currently gracing the western horizon at dusk. Owing to a favourable set of circumstances, the brightest planet is visible long after sunset. How late can you see it set in the British Isles? For those north of the Arctic Circle, Venus is presently circumpolar and doesn’t set at all!
As dusk fades to dark on Thursday, 17 January, observers in the British Isles and Western Europe can see the rising 10-day-old Moon less than 1 degree away from first-magnitude star Aldebaran in the constellation of Taurus. Grab your binoculars to enjoy the sight of the gibbous Moon amid the Hyades open star cluster too.
