A meteor shower that stands out against the relatively low springtime meteor rates
|Main Activity Dates||Apr 16–25|
|Peak Rates||Apr 22d 13h UT|
|Best Observed Rates||Night of Apr 21-22|
|Visibility each night (UK)||Visible all night|
|Moonlight issues at maximum||
First Quarter Moon
Meteor rates are generally low for northern hemisphere based observers during the first half of the year, but the Lyrids break this trend. The peak ZHR is normally ~15-20, but short-lived, more active bursts have been recorded sometimes, most recently in 1982 (when ZHRs were ~90). Trails are usually short-lived but fireballs are sometimes reported.
Lyrid meteors are typically medium to swift speed, hitting the atmosphere at around 50 km/s. The parent body is Comet Thatcher of 1861 whose orbital period is about 415 years and is now probably 110 AU away (1 astronomical unit is the Earth–Sun distance).
The Lyrid maximum is predicted for approx 13h UT on April 22. From the UK, the best rates are normally to be seen just before dawn but in 2021 a waxing Moon will be visible all night. The Lyrid radiant (see chart below), lies on the Hercules–Lyra border at the peak (and not quite as near Vega as some people expect). It is low in the sky at the start of the night and gains altitude as the night progresses, leading to increasing observed rates. The chart below shows how it has climbed well clear of the horizon and is quite high in the eastern sky by the early hours of the morning.