Watch the king of the planets turn on its throne

Jupiter is two months past opposition on 10 August, so you need to be looking low in the southern sky of the British Isles around sunset if you wish to catch the solar system’s largest planet at its best. If you time it right and the weather obliges, Jupiter’s Great Red Spot makes multiple appearances while the planet’s Galilean moons play hide and seek. Welcome to our August 2019 Jovian observing guide.

Astronomy Now Online brings you a powerful interactive global Almanac and UK-based all-sky star maps — the first of a new suite of tools to help plan your observing sessions and travel.

A new analysis of data from NASA’s Cassini mission in combination with lab experiments contradicts the leading theory that the striking colour of Jupiter’s Great Red Spot is due to reddish chemicals upwelling from below.