There is something glorious about seeing the silvery moon contrasted with the blood-red light of Antares, the giant star in Scorpius, the Scorpion. Tonight offers an excellent chance to see this pairing.
The chart shows the view looking south from London at midnight as 16 May becomes 17 May. The moon will be full with 99% of its visible surface illuminated. It will be about 3.5 degrees away from Antares (for reference the full moon itself measures about 0.5 degrees across).
Antares is the 15th brightest star visible in the sky and the brightest star in Scorpius. It slowly varies its brightness by a factor of about 0.75 but does not follow a regular cycle. This makes it a “slow irregular variable star”, a poorly understood class of variable star which can encompass a wide variety of causes.
This week, the pairing is easily visible from the southern hemisphere too. In general, the farther south you go, the higher in the sky Scorpius appears, and so the easier it is to see. From Sydney, Australia, Antares and the moon will be high in the eastern sky, towards the zenith, at midnight as 17 May becomes 18 May.
