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.
This two-tone, almost yin-yang like image of Iapetus, Saturn’s third largest moon, is the view Cassini was privilege to when it did its second closest approach of the satellite earlier this year.
NASA’s Cassini probe has entered a new series of orbits which bring it close to Saturn’s icy moons. It has already captured the highest resolution view yet of Rhea, Saturn’s second largest moon.
NASA’s Cassini spacecraft has been in orbit around Saturn since 2004, studying the giant planet, its rings and its moons. Among the myriad microscopic grains collected by Cassini, a special three dozen stand out from the crowd. Scientists conclude these specks of material came from interstellar space — the space between the stars.
