ASTRONOMY FOR BEGINNERS

LYRID METEOR SHOWER

WHEN: MID- TO LATE-APRIL

The Lyrid meteor shower is active between 16-➤› April, with peak rates expected on the night of ➤➤/➤3 April. On this night, if conditions are perfect, you’ll be able to see around 18 meteors per hour.

Meteor shower activity is quantified by Zenithal Hourly Rate (ZHR), measured in meteors per hour. A shower happens when Earth passes through the wide debris stream of a comet. Usually sparsely populated, streams can become denser towards their core. Particles the size of a grain of sand from within the stream vaporise when they enter Earth’s atmosphere, producing streaks of light we call meteors.

The particles are on parallel orbits around the Sun. When they enter our atmosphere, our perspective makes it look as if they emanate from a small area of sky called the shower ‘radiant’. A shower’s ZHR assumes an overhead radiant, as well as perfect sky conditions. Anything short of these requirements lowers the visual hourly rate, which is the actual number of meteors seen.

Over time, the radiant drifts slowly against the stars, our chart showing where it will be on peak night. For a meteor to be a Lyrid, it must appear to be coming from the radiant position. As darkness falls, the star Vega is low above the northeast horizon, gradually climbing in altitude to be virtually overhead before dawn.

To get the best views, find a dark area away from streetlights, and avoid looking at artificial lights (including mobile phones!). Allow ➤0 minutes for your eyes to fully adapt. Look approximately two-thirds up the sky (60° altitude), slightly away from the radiant position – trails will appear longest around 90° from the radiant. No Moon interference in ➤0➤3 means this year’s Lyrid peak is very favourable. Unfortunately, this isn’t the case for the Eta Aquariid shower, which peaks on the morning of 6 May.