Observers in the UK with a clear sky at dusk should try to locate Venus low in the western sky an hour after sunset. The 3-day-old slim crescent Moon acts as a convenient guide, located some 12½ degrees (or half the span of an outstretched hand at arm’s length) to the upper left of the brightest planet. Conspicuous star Aldebaran lies in the same low-power binocular field of view as the Moon too. Note that the size of the lunar crescent has been enlarged for clarity. AN graphic by Ade Ashford.Observers in Western Europe should make the most of fine weather to locate Venus low in the western sky an hour after sunset, particularly on Wednesday 18 April when the 3-day-old slim crescent Moon acts as a convenient guide, located some 12½ degrees (or half the span of an outstretched hand at arm’s length) to the upper left of the brightest planet.
Stargazers in the British Isles with a clear sky around 10pm this evening should note the Pleiades (Seven Sisters) forming a right-angled triangle with Venus and the Moon in the deepening twilight, but don’t leave it much later as the brightest planet sets around 10:43pm as seen from the heart of the UK (stated times are in BST).
Prominent first-magnitude star Aldebaran lies in the same low-power binocular field of view as the Moon too. In the small hours of 19 April, the waxing lunar crescent actually occults (passes in front of) Aldebaran as seen from central and northern Russia, north and eastern Scandinavia, the north of Greenland and northernmost Canada.
Currently setting over four hours after the Sun as seen from the heart of the UK and visible in the west-southwest at dusk, dazzling Venus is about to hit peak brightness in the constellation of Pisces. The planet attains magnitude -4.8 on Friday 17 February — some 21 times the luminosity of brightest star Sirius gracing the southeast horizon as darkness falls.
The orbits of Jupiter’s large Galilean moons Io, Europa, Ganymede and Callisto are presently almost edge-on to our line of sight, causing the moons to regularly eclipse and occult each other. Multiple shadow transits are also on view!
Overall, about 1 kg of material is escaping our atmosphere every second. Every day, around 90 tonnes of material escapes from our planet’s upper atmosphere and streams out into space. Although missions such as ESA’s Cluster fleet have long been investigating this leakage, there are still many open questions. How and why is Earth losing its atmosphere?
