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.
Many of you may have tracked down an asteroid with binoculars or a telescope, but have you ever seen one with the naked eye? If not, then June presents you with an opportunity to see the brightest, 4 Vesta, at a close opposition. What’s more, ringed planet Saturn lies close by to act as a convenient guide.
Although Jupiter close to opposition may be stealing the other naked-eye planets’ thunder, there’s lots more to see if you’re an early riser on the weekend of 5–6 May. About an hour before sunrise finds Mars and Saturn less than the span of an outstretched hand at arm’s length apart in the UK southern sky, with the waning gibbous Moon acting as a convenient guide to each planet on successive mornings.
The existence of a fifth giant gas planet at the time of the solar system’s formation — in addition to Jupiter, Saturn, Uranus and Neptune that we know of today — was first proposed in 2011. Now astrophysicists at the University of Toronto have found that a close encounter with Jupiter about four billion years ago may have resulted in the fifth giant planet’s ejection from the solar system altogether.
