Those with a good view of the eastern horizon in the pre-dawn skies of tomorrow should keep an eye open for the Eta Aquarid meteor shower. The chart shows the view looking east from London at 04:00 BST on 5 May. The meteors will emanate in all directions from the radiant point but the low altitude and the light from the waxing gibbous moon will make observing more challenging. Observers should expect around 10 meteors an hour at most once their eyes have adapted to the dark, which usually takes between 20 and 40 minutes. Those in the southern hemisphere should fare better. The radiant will be higher in the sky, and this could double the number of visible meteors. In common with all meteor showers, the Eta Aquarids are dust grains that were once in the tail of a comet. In this particular case, the comet in question is the famous Halley’s comet. Last seen in Earth’s night sky in 1986, it won’t return until 2061, when it will replenish the Eta Aquarids meteoroid stream.