There is a magnificent sight to behold this week – but you will need to set your alarm clock. In the early hours of Thursday, Mars will disappear completely behind the full moon, an event known as an occultation. The chart shows the view looking west from London at 4.30am GMT. Throughout the preceding evening, on Wednesday, the moon will inch its way closer to Mars in the night sky. At about 4.58am GMT on Thursday, Mars will disappear behind the moon’s western hemisphere. It will reappear about an hour later from behind the eastern limb. Across the UK, the timing could vary by several minutes depending upon where exactly you are located. More widely, the occultation is visible across northern Europe, Greenland and North America. The tip of north Africa will also catch a view. Look up local timings online as they could vary by a number of hours depending on country. The event is visible with the naked eye and Mars itself will be at its brightest, having passed closest to Earth on 1 December. On Thursday it will be directly opposite the sun in the sky, thus reflecting the most light it can.