Starwatch: Mercury is the big prize in a delightful trio | Astronomy

Close out the UK bank holiday with an absolutely delightful sight this evening.

Around 21.00 BST, a wafer-thin crescent moon will hang between the star Aldebaran and the planet Mercury. Begin your search as twilight begins to fall, and look low towards the western horizon. By 9pm, you should be able to see the three celestial objects.

Aldebaran is a red giant star some 65 light years from Earth. It is the brightest star in the constellation Taurus, the Bull. In contrast, at roughly 170,000 miles (380,000km) away, the moon is just 1.25 light seconds distant.

On this particular night, it will be a beautiful new moon, with just 3.5% of its visible surface illuminated. Catching a glimpse of this alone would make the effort worthwhile. But the real prize tonight lies just beyond: the inner planet Mercury. Currently situated 72m miles from Earth, Mercury is 6.4 light minutes away. Although this trio will be setting rapidly, those with a particularly low horizon should keep watching. If the air is still, around 21.33 BST, the Pleiades star cluster may also just be visible beyond Mercury.

The chart shows the view looking west-north-west from London at 21.00 BST. The grouping will be very difficult to see from the southern hemisphere.