Ceres, the brightest and closest dwarf planet to Earth, reaches opposition at 12am BST on 29 May. Also the largest of the minor planets between the orbits of Mars and Jupiter, Ceres is an easy binocular object attaining magnitude +7 in early June amid the stars of Scorpius, where it may be found some 18 degrees above the southern horizon at 1am BST in the UK, or by 10:30pm BST at the end of June. Ceres lies about 9 degrees (or two 10×50 binocular fields of view) north of first-magnitude Antares, the brightest star in Scorpius. This illustration shows field stars to magnitude +7.5. Click the graphic for a PDF finder chart suitable for printing. AN graphic by Ade Ashford.On Sunday, 26 May at 21:17 UT, 1 Ceres, the nearest and brightest of the dwarf planets and the largest minor planet inside the orbit of Neptune, passed closest to Earth for this year. At this instant, Ceres was 1.7513 astronomical units, or 262 million kilometres (162.8 million miles) from our planet.
Ceres presently lies in the constellation of Ophiuchus, the Serpent Bearer, but the dwarf planet’s westerly motion relative to the stars carries it into Scorpius on 29 May where it resides until 22 June.This artist’s impression is based on a detailed map of the surface compiled from images taken by NASA’s Dawn spacecraft in orbit around dwarf planet 1 Ceres. Some 946 kilometres (588 miles) in diameter, Ceres orbits the Sun between Mars and Jupiter once every 4.6 years. It was discovered by Giuseppe Piazzi in Sicily on 1 January 1801. As seen from Earth, however, the angular size of 1 Ceres never exceeds 0.9 arcseconds, so it will appear starlike in a typical backyard telescope. Image credit: ESO/L.Calçada/NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/Steve Albers/N. Risinger (skysurvey.org).Ceres reaches opposition close to 12am BST on 29 May and shines at its peak magnitude of +7.0 for 2019, fading to +7.8 by the end of June, hence it’s a comfortable binocular or small telescope target — if you know exactly where to look. Click here for a printable PDF version of the finder chart at the top of the page.
As viewed from the UK, Ceres is currently highest in the sky close to 1am BST, or by 10:30pm BST at the end of June, when the dwarf planet is just 18 degrees high in the south as seen from the centre of the British Isles.
Ceres is also occulted (hidden) by the Moon on 15 June as seen from Russia (central and east), Kazakhstan (northeast), China (north and east) and Japan.
As NASA’s Dawn spacecraft heads for its historic rendezvous with dwarf planet Ceres next week, further mysteries unfold on the small world. Now seen in higher resolution, a volcano-like bright spot has a nearby companion.
Although Jupiter close to opposition may be stealing the other naked-eye planets’ thunder, there’s lots more to see if you’re an early riser on the weekend of 5–6 May. About an hour before sunrise finds Mars and Saturn less than the span of an outstretched hand at arm’s length apart in the UK southern sky, with the waning gibbous Moon acting as a convenient guide to each planet on successive mornings.
It seems that the more we see of Pluto, the more fascinating it gets. This latest image, from the heart of Pluto’s heart feature, shows the plains’ enigmatic cellular pattern as well as unusual clusters of small pits and troughs. Adding to the intrigue is that even at this resolution of 250 metres, no impact craters are seen, testifying to the region’s extreme geologic youth.
