How many Perseids might you expect to see?
The number of meteors seen is often less than theoretical figures
If you read some of the media coverage of meteor showers like the Perseids, you might think that, at their peak, these events see a near-constant rain of bright shooting stars blazing across the sky. Real meteor showers – while captivating and absolutely worth observing – are rarely like this. One number that’s often mentioned is the Zenithal Hourly Rate, or ZHR; this is a theoretical number of meteors that would be visible, on average, over an hour with the radiant of the shower at the zenith and the viewing occurring under perfect sky conditions. The ZHR isn’t a good indicator of how many meteors you can expect to see every hour, however; that figure will be lower because of things like light pollution and the typically lower radiant at the observing time. It’s possible to roughly estimate how many Perseids you might spot, on average, near the peak of the shower; such a calculation suggests that while observing at around 3am (BST) on the night of the peak, a group of observers at a suburban site – where the naked-eye limiting magnitude is, say, +5 – could potentially see a rate of about 25 Perseids an hour or so.