On the night of 27 January, the moon passes in front of the Pleiades star cluster, temporarily hiding (occulting) some of its brightest members from view.
The Pleiades, also known as the seven sisters, lie about 440 light years away in the constellation Taurus, the Bull. They are one of the most recognisable structures in the winter sky. The stars were all born from the same giant cloud of molecular gas. Although in time they will be dispersed through the galaxy, at only 100m years old, they remain a relatively tight-knit community of stellar siblings.
By contrast, the moon is a little over a light second away, close enough that its motion against the stars can be followed over the course of an hour. So, to fully appreciate the occultation, prepare to spend an hour or two in the late evening watching as the moon passes through the cluster.
The dark side of the moon is facing its direction of motion, and this means that the stars will be easy to see ‘wink out’, reappearing about an hour later from behind the opposite lunar hemisphere.
The chart shows the view looking south-southeast from London at 9pm on 27 January. This is about 10 minutes before the first of the seven sisters, Taygeta, will disappear from view. However, check online for local times because locations, even across the UK, can alter the times of disappearance and reappearance by about 15 minutes.
