Every August sees the arrival of the meteor shower known as the Perseids. With the practically guaranteed good weather inviting us to enjoy the night, an almost new moon and clear dark skies, we will once again be regaled with a spectacular show. The best time to see it is between August 12 and 13. At the peak of the display you can see up to 100 meteors an hour if you are somewhere far from sources of light contamination. The glowing lights are visible for a few seconds and move at an extraordinary speed of about 59 kilometers per second.
The origin of the meteor shower and how to see it
The Perseids have their origins in comet 109P/Swift-Tuttle, whose tail intersects the Earth’s orbit. This interesting phenomenon is produced by the remains of this comet as it enters the Earth’s atmosphere. Forecasts indicate that it will be possible to see a maximum of one or two meteors a minute. Of course, the fragments have a very small size and mass and do not pose any risk. In view of the fact that there will be a new moon and the sky will be very dark on 14 August, we’re guaranteed a spectacular show. All you have to do is follow some basic recommendations.
In any case, the phenomenon lasts several weeks, from mid-July through to the end of August. It also overlaps with other less-known and less active meteor showers , originating in the 96P/Machholz, 7P/Pons-Winnecke and 169P/NEAT comets.
It is easy to locate the radiant of the Perseids –the point in the celestial sphere where they appear to come from. All you have to do is find the constellation of Cassiopeia, a large W in the sky, whose opening faces north. The meteors seem to be showering down on us from the clearly visible double cluster, and which you can find by tracing the prolongation of the line that appears to join two of the brightest stars in Cassiopeia, as shown in the diagram.
Perseus: the hero, the myth and the constellation
Stars of the summer include particularly Perseus, who gives his name to the meteor shower. The story of this Greek hero is marked by fate and prophecy. Son of Danae and Zeus and grandson of Acrisius, the king of Argos, he was to kill and succeed the king. One of Titian’s most famous paintings depicts the moment in which he is engendered by the Lord of Olympus, converted into a golden rain, maybe one of the most sensual images in the Renaissance. His is a sad story, featuring an endless series of fratricidal struggles, ill-fated romantic entanglements, conspiracies and jealousy both among humans and gods. But it is also an epic story: Perseus fights hand-to-hand and kills monsters that were said to be indestructible, such as Medusa who turned all who gazed into her eyes to stone. Without doubt, this is an epic as remarkable as “The Odyssey”, with a protagonist who is as intelligent but probably more daring. Perseus is as much a hero as Odysseus, who is however much better known. This was a true Greek tragedy but, interestingly enough, there is no surviving play on this theme; there is one play by Calderón de la Barca written long after, and entitled “Andromeda and Perseus”.
As for the constellation itself, it can be seen during fall nights in the northern hemisphere; although, due to its declination, it can be also be seen at other times of the year. It contains various fairly impressive objects, ranging from regions with very young star formations (such as IC1333), and including star associations (M34, also known as NGC1039), through to clusters of galaxies such as Abell 426. A perfect gift for fall (or for spring and so).
David Barrado Navascués
European Space Astronomy Center (ESAC, Madrid)