This looping movie shows the position of Mercury some 14 degrees above the eastern horizon one hour before sunrise as seen from Sydney, New South Wales from 26 April to 10 May 2018. The innermost planet attains a favourable elongation of 27 degrees west of the Sun on the last morning of April in Australasia, meaning that it can be seen in a dark sky before the onset of astronomical dawn throughout the period of this animation. For scale, the view is 80 degrees wide, or four times the span of an outstretched hand at arm’s length. AN graphic by Ade Ashford.Have you ever seen the closest planet to the Sun? If you wish to tick Mercury off your to-see list, particularly if you live in the Southern Hemisphere, now’s the time to be scrutinising the eastern sky shortly before sunrise for the planet’s rosy glow. On 29 April (30 April in Australasia), Mercury attains a greatest westerly elongation of 27 degrees from the Sun – just 4 percent short of the farthest it can ever appear from our parent star.
Observing conditions for Mercury under southern skies are so good over the next fortnight (weather permitting) that skywatchers in Australia and New Zealand can comfortably view the planet in a truly dark sky from a viewing location that offers an unobstructed view of the east-northeast horizon about 1½ hours before sunrise.
Mercury’s magnitude grows from +0.7 to zero over the next two weeks, but atmospheric dimming close to the horizon will make it appear up to a magnitude fainter. Even so, the innermost planet will be a conspicuous dawn object for Southern Hemisphere observers through to the middle of May.
The old Moon gets close to Mercury and UranusObservers in Australasia looking low in the eastern sky an hour before sunrise on Monday, 14 May 2018 can see an attractive conjunction between magnitude -0.2 Mercury and the slim crescent of a 27-day-old Moon in the constellation of Pisces. In this simulated seven-degree 7×50 binocular view from Sydney, New South Wales, there’s the added incentive of glimpsing magnitude +5.9 planet Uranus in the same field of view. Uranus lies just over the constellation border into Aries, one-fifth of a degree from a similar brightness star known as HIP 8588. Don’t confuse Uranus with magnitude +4.3 star omicron (ο) Piscium above in the same binocular field. AN graphic by Ade Ashford.Mercury crosses the constellation border from Cetus into Pisces on 1 May and has a close encounter with an old crescent Moon on 14 May. On this date, observers in Australasia should look low to the east-northeast horizon an hour before sunrise to see the 27-day-old Moon just 2 degrees to the right of the magnitude -0.2 planet. Small telescopes and binoculars magnifying 20× or less will show the pair in the same field of view. And as a bonus for owners of binoculars, magnitude +5.9 planet Uranus also lies 2¼ degrees to the left of Mercury on this morning!
When a full Moon makes its closest pass to Earth in its orbit it appears up to 14 percent bigger and 30 percent brighter than average, making it a supermoon. This month’s full Moon on Monday 14 November is the closest Moon to Earth since 26 January 1948. The Moon won’t be this super again until 25 November 2034!
Observers should direct their gaze to the southern sky at dusk on Saturday, 12 January to view the 6-day-old waxing Moon in the constellation of Pisces. Look a little closer around 6pm GMT in the UK this night to see Mars as a magnitude +0.6 orange-coloured ‘star’ above the lunar crescent. If you own wide-angle 7× or 8× binoculars, you can see the Moon and Red Planet in the same field of view.
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.
