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.
Observers in Western Europe with a clear view to the south-southeast at nautical dawn can watch the changing configuration two prominent naked-eye planets over the next few mornings, culminating in a beautiful close conjunction of Venus and Jupiter on 22 January 2019.
As dusk fades to dark on the evening of Tuesday 15 November, observers in the British Isles and Western Europe can see the rising 16-day-old Moon less than 2 degrees away from Aldebaran in the constellation of Taurus. While an occultation of the star occurs around 17h UT for observers in Japan, central Asia and the Middle East, skywatchers in the UK will have to settle for a near miss.
The space environment around a planet plays a key role in determining what molecules exist in the atmosphere – and whether the planet is habitable for life. New research shows that Venus has an “electric wind” strong enough to remove the components of water from its upper atmosphere, which may have played a significant role in stripping Earth’s twin planet of its oceans.
