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.
Set your alarm for 6am GMT if you wish to see three naked-eye planets in the UK dawn sky this week. Find a location that offers an unobstructed view of the horizon from southeast to south and let the waning Moon be your guide to locating Jupiter, Mars and Saturn on successive mornings from 7 to 11 February.
On Saturday, 2 March 2019, observers in Western Europe should seek a location offering a level and unobstructed southeastern view at civil dawn (some 36 minutes before sunrise in the heart of the UK) to have a chance of seeing the 25-day-old waning crescent Moon between Venus in Capricornus and Saturn in Sagittarius with the unaided eye.
Late into the evening of Sunday 5 February, UK observers can see the waxing gibbous Moon pass close below bright star Aldebaran in the constellation of Taurus. Skywatchers in southern Europe will see the Moon cover the star.
