Starwatch: moonlight puts a damper on the Perseid show

This week one of the most reliable annual meteor showers will be on show. The Perseids will reach their peak activity over the next few days. Start looking tonight, particularly in the early hours of the morning, then again tomorrow night and on Wednesday. The meteors are small particles of dust, left in space from the tail of Comet Swift-Tuttle, that burn up high above Earth. Each particle enters our atmosphere at a velocity of around 130,000 miles per hour.

The chart shows the position of the meteors’ radiant in the night sky this week. The meteors themselves will appear to fan out across the night sky from this point. The Perseids are renowned for being numerous and bright. This year, however, the moon will be close by and just past its last quarter phase. This means there will be a significant amount of moonlight that will hamper the view of the fainter meteors. Under perfect conditions, the Perseids can deliver 100 meteors an hour, but even from a dark sky, well away from street lamps, the moonlight this year will wash out probably half of them.

Unfortunately for those in the southern hemisphere, the meteor shower becomes more difficult to see the further south you are located.