Starwatch: Mars, in opposition, is a radiant beacon

Starwatch chart 16 July 2018

Late birds with a good south-eastern horizon will probably have already noticed Mars in the dead of night. In the early hours of the morning, it is a radiant beacon, shining low in the constellation of Capricornus. During the next fortnight, the planet is going to brighten steadily as it heads for its closest approach to Earth since 2003. Mars makes a close approach every two years. It happens when our planet “laps” Mars, passing between it and the sun. The moment is known as opposition because Mars is in the opposite hemisphere of the sky to the sun. Mars’s opposition this year takes place on 27 July. The chart shows the view for midnight tonight when Saturn is clearly visible as well. Saturn appears in the neighbouring constellation of Sagittarius and the two planets will be the bright objects in that part of the sky. They will form a nice contrast: the subtle yellow of Saturn and the vibrant red of Mars.