The Perseids, one of the best meteor showers of the year, reaches its peak on the night of August 12-13, not long after New Moon, so conditions are quite favourable. Some will be visible each night from 23 July to 20 August.

The chart above shows the stars for midnight BST 12 – 13 August 2021

At its peak the shower is expected to produce a Zenith Hourly Rate (ZHR) of about 80 meteors per hour. From Edinburgh the radiant of the shower will be 38° above the NE horizon at midnight. This means we might be able to see around 50 meteors per hour, since the radiant will be relatively high in the sky. And remember, you can actually see some Perseids from as early as 23 July  all the way up to the peak.

The Moon will set at 22:37 BST with just 24% illumination, so conditions are pretty good. This will also mean that there is a beautiful crescent Moon setting in the West on that evening.

The radiant is the point in the sky that the meteors appear to come from, which in this case is in the constellation of Perseus. To view meteors don’t look directly at the radiant itself but at about 30–40° away from it, then meteors will show reasonably long trails without being too spread out.

Meteor showers happen when we pass through the debris left behind by comets and asteroids. The comet responsible for the Perseid shower is 109P/Swift–Tuttle and we pass through this cloud every year in Jul-Aug. When these tiny objects hit our atmosphere they burn up and appear as “shooting stars”.

Alan Pickup says in his August 2021 Sky Diary: Records of the shower, however, date back over two millennia while its whimsical name as the Tears of St Lawrence may have a macabre origin in early Christian tradition. The saint was martyred on August 10, AD258, some say by being roasted alive over an iron grill – with the not unconnected consequence that he is now regarded as the patron saint of chefs.

Some useful times on 12 August 2021 (BST)

Sunset: 20:58
Nautical darkness: 22:39 – 03:54

Mark Phillips

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