Ceres reaches opposition on January 31, 2018

Dwarf planet Ceres, the largest object in the asteroid belt, reaches opposition on January 31st. It will peak at magnitude +6.8, as it moves retrograde in Cancer. Bright stars Castor (α Gem - mag. +1.6) and Pollux (β Gem - mag. +1.1) in Gemini can be found about 20 degrees further west. Since Ceres travels quickly with respect to the "fixed" background stars, it can be tracked on a nightly basis. Although Ceres is too faint to be spotted with the naked eye, it's easily visible with binoculars and small telescopes. In addition, this opposition is very favourable as this dwarf planet peaks close to its maximum possible brightness. At opposition, it will be 1.602 AU (approx. 239.7 million kilometres or 148.9 million miles) distant from Earth.

On January 1, 1801, Italian catholic priest and astronomer Giuseppe Piazzi discovered Ceres, originally believing it to be a comet. This new object, between the orbits of Mars and Jupiter, was initially classified as a planet and given its own planetary symbol. However when more objects, all small, were discovered in the same region of the Solar System, the general term "asteroid" was coined to describe them. Much later in 2006, the International Astronomical Union (IAU) defined a new classification of dwarf planet, of which Ceres is now a member. Ceres has a diameter of 945 kilometres (590 miles).

Ceres will gradually fade in brightness after opposition, but will still remain visible with binoculars and small scopes over the coming few months. Positions of Ceres in the chart and table below are at 0 UT.

Ceres - January 15 to March 12, 2018 - Finder Chart - pdf format (credit:- freestarcharts)

Ceres Data Table