The Perseids is perhaps the most well-known of all the meteor showers.
After several months of long summer nights it heralds the beginning of the night sky observer’s calendar with an often spectacular display. It has been observed for centuries with some of the earliest recorded observations were made in China almost two thousand years ago. The Perseids occur when the Earth’s orbit passes through the trail of debris left by the comet Swift–Tuttle which orbits the sun every 133 years. The connection with Comet Swift-Tuttle was suggested a few years after the comet’s co-discovery in 1862 by American Astronomers Lewis Swift and Horace Parnell Tuttle. This was the first time that a meteor shower had been associated with a comet. The nucleus of comet Swift –Tuttle is around 26km in diameter and its orbit takes it into close proximity to the Earth-Moon system. It is due to make its next appearance in 2106.
The Perseids shower is active between July 17 and August 24. Although it has a long duration, it has a very strong and short duration peak around August 12. You will be able to observe Perseid meteors all across the sky but the shower is visible primarily in the Northern Hemisphere because of the shower’s radiant (the point where all meteors appear to originate) is in the constellation of Perseus. (At around midnight in the UK Perseus will be in the North-West at about 40 degrees altitude).
Perseid meteors are relatively bright due (in part) to their high average velocity. This is in excess of 61km per second (Geminid meteors, for example, average approximately 35km per second). Peak activity can reach over 100 meteors per hour and on the night of peak activity it is not uncommon for one of our cameras to capture several hundred meteors. This year the Perseids peak coincides with a bright waning gibbous moon, the light of which will drown out some of the less bright meteors. Visual observers can expect to see significantly fewer meteors and even under transparent skies observed rates may be less than 40-50 per hour. Even so this is still a good show.
Meteor rates will be higher before dawn because the side of the earth moving into the stream encounters more debris. To give yourself the best chance to see Perseid meteors go outside after midnight on the morning of August 12. Give your eyes to time to adjust to the dark, look straight up and enjoy the spectacle. Whilst watching the sky avoid glancing at your smartphone as it will reduce your night-time visual acuity. Alternatively, why not try capture some meteors on camera. The American Meteor Society has published some excellent guidance on how to photograph meteors.
One of the benefits of a national camera network is that there is a good chance of clear skies somewhere where there is a UKMON camera. The UKMON network of cameras will be monitoring the Perseids shower and during peak activity. You can join us on Facebook and Twitter where we will publish some of our best images.
Perseid fireball from 2015 recorded by Wilcot:
Perseid fireball from 2014 recorded by Clanfield:
Perseid fireball from 2015 recorded by Cardiff: