Around 6:30am GMT on Friday 25 November, as nautical twilight starts for the centre of the UK, the 25-day-old waning crescent Moon lies just 2½ degrees away from largest planet Jupiter low in the southeastern sky. This juxtaposition of the two brightest celestial objects in the dawn sky will be nicely framed in a typical binocular. Look for fourth-magnitude star theta (θ) Virginis in the same field of view, a double star in small telescopes. AN graphic by Ade Ashford.For early risers in the British Isles, Jupiter can be found in the constellation of Virgo low in the east-southeast from 4am GMT. For those of you not prepared to brave the cold of such small hours, the 25-day-old waning crescent Moon lies within the same binocular field of view as the magnitude -1.8 largest planet at the start of nautical twilight on Friday 25 November. Look low in the southeast around 6:30am GMT to see this beautiful conjunction.
The configuration of Jupiter’s four Galilean moons Io, Europa, Ganymede and Callisto in the UK dawn twilight of Friday 25 November 2016 as seen with an erect-image telescope (north is up and east to the left). AN graphic by Ade Ashford.In binoculars and small telescopes you will also notice fourth-magnitude star theta (θ) Virginis a degree (or two lunar diameters) below the Moon. This object, also known as 51 Virginis, is a multiple star with components of magnitude +4.4 (a close double) and +9.4 separated by 6.4 arcseconds.
Turning our attention back to Jupiter on the UK morning of 25 November, owners of supported powerful binoculars and telescope owners can see all four of the planet’s Galilean Moons — Io, Europa, Ganymede and Callisto. Observers in possession of quality instruments of 70mm aperture and larger capable of 150x magnification or more can observe transits, eclipses and shadow transits of these large Jovian moons on other mornings. You can obtain detailed predictions via our interactive online Almanac.
As a taster for observers in the British Isles, Io is eclipsed by Jupiter’s shadow at 7:17am on 22 November; the shadow transit of Io ends at 6:47am on 23 November; Io emerges from occultation by Jupiter at 4:51am on 24 November and Ganymede is eclipsed by Jupiter’s shadow at 5:19am on 26 November. Transits of Jupiter’s Great Red Spot (GRS) occur at 7:48am on 26 November, 5:18am on 29 November and 6:57am on 1 December (all times GMT).
Inside the magazine
For a comprehensive guide to observing all that is happening in next month’s sky, tailored to Western Europe, North America and Australasia, obtain a copy of the December 2016 edition of Astronomy Now.
A decade-long question about the nature of dark spots on Europa’s surface has potentially been solved, with scientists suggesting that these spots are likely signs of irradiated sea salt from a subsurface ocean, deposited onto the surface through interactions with its rocky seafloor. If this is indeed the case, then these findings are an important consideration for assessing the habitability of the planet and whether it could support life or not.
Look to the north-west this evening (21 May), soon after sunset, to enjoy a spectacular coming together of brilliant Venus and shy and elusive Mercury.
A giant mound near the Moon’s south pole appears to be a volcanic structure unlike any other found on the lunar surface, according to new research by Brown University geologists. The formation, known as Mafic Mound, stands about 800 metres tall and 75 kilometres (47 miles) across, smack in the middle of a giant impact crater known as the South Pole-Aitken Basin.
