The Great Red Spot (GRS) is the solar system’s largest known storm, an Earth-sized anticyclone that has raged in the atmosphere of Jupiter for at least two centuries. But recent observations from Earth and space suggest that this iconic Jovian feature is undergoing huge changes that could herald its demise.
On 18 June at the end of civil twilight in the UK, planets Mars and Mercury lie slightly less than one-quarter of a degree apart in the constellation of Gemini. Observing this conjunction will be a challenge from the UK as the pair will be just 5 degrees high in the west-northwest at civil dusk in bright twilight, which is about 50 minutes after sunset for London.
Jupiter, the solar system’s largest planet, reaches opposition on 10 June in the constellation of Ophiuchus (the Serpent Bearer) and is visible low in the southern sky of the UK through the night. Observers with small to medium aperture telescopes can see a number of shadow transits of Jupiter’s Galilean moons and view the planet’s Great Red Spot throughout June.
Have you ever seen a dwarf planet? Of the five within our solar system recognised by the International Astronomical Union – Ceres, Pluto, Haumea, Makemake and Eris – only Ceres can be considered bright and easy to locate. It reaches opposition in the constellation of Scorpius on 29 May at magnitude +7, an easy binocular object if you follow our guide.
Observers in the UK with clear skies around 1am BST on Tuesday, 21 May can see Jupiter, the solar system’s largest planet, just 4 degrees from the waning gibbous Moon low in the south-southeast. At this time both the Moon and Jupiter fit within the same field of view of binoculars magnifying less than 10×, while telescope users can also view Jupiter’s Great Red Spot.
UK skywatchers with a view low to the west between midnight and moonset on Saturday, 11 May 2019 can see the 6-day-old waxing crescent Moon close to Messier 44, otherwise known as Praesepe, or the Beehive Cluster. Later, observers on North America’s Eastern Seaboard can see the Moon pass in front of this glorious open cluster just before local midnight on 10 May.
If you’re bemoaning the current dearth of bright planets in the evening sky, or light pollution prevents you from viewing a multitude of spring galaxies, don’t give up – there are always attractively coloured double and multiple stars to view. Join us on a tour of the Northern Hemisphere constellation of Boötes (pronounced Bo-oh-tees), the Herdsman, easily located due to its brightest star, Arcturus.
Owls may be scarce near your favourite viewing spot, but the Northern Hemisphere spring sky contains one celestial owl that you can track down in small telescopes – Messier 97 (NGC 3587). Commonly called the Owl Nebula, M97 is a planetary nebula discovered by Pierre Méchain in 1781 that is currently ideally placed for observation almost overhead at nightfall in the constellation of Ursa Major, the Great Bear.
Mercury attains a very favourable western elongation of almost 28 degrees from the Sun on 11 April, which means that the innermost planet is a morning object in the eastern sky before sunrise. Antipodean skywatchers are in the enviable position of being able to see Mercury and Venus close together for several mornings in a dark sky before the onset of astronomical twilight.
For ten nights starting 5 April 2019, asteroid 2 Pallas and unmistakable Arcturus – the northern celestial hemisphere’s brightest star – lie within the same field of view of typical 8× binoculars. Also, don’t miss magnitude +7.9 Pallas’s very close conjunction with magnitude +2.7 star eta (η) Boötis at 22h UT (11pm BST) on the night of 10 April.