Perseus, the hero. Perseids (Aug 11-13, 2010).
August 11th, 2010
Some stories have a lot of staying power, others not so much. One of the deciding factors seems to be chronology, with earlier accounts faring better than later ones. So while it may seem questionable that any modern artist, or sports hero, or military/political figure will still be well-known several hundred years hence, some of the ancient ones, from a few thousand years prior, are practically commonplace.
Thus it could happen that one evening while stretching your Achilles tendon, following a run of herculean effort, you might end up on your back staring up into the night sky with your gaze wandering through the constellations of Cepheus, Cassiopeia, Andromeda and Perseus. And this lovely sight (assuming the modern light pollution permits you to see it at all) might invoke the memory of storytime from the days of your youth.
The story of Perseus is an old one, having been told, retold, and revamped many times. By legend, the son of DanaĆ« and Zeus (not Poseidon), the young Perseus is cast into the sea, along with his mother, and is later found and raised by the fisherman Dictys. To protect his mother from the unwanted advances of his “adoptive uncle” Polydectes, Perseus undertakes a quest to retrieve the head of Medusa (aka Uma Thurman). To aid him on his journey he is bequeathed with certain other-worldly gifts: a shield from Athena, a sword from Zeus, and winged sandals from Hermes (these, no doubt, at least as comfortable as winged, Converse low tops). With the aid of his gifts he achieves his goal, as heroes are wont to do, and heads home.
Along his return, which is typically when most adventures finally get interesting, he encounters the beautiful daughter of King Cepheus and Queen Cassiopeia, princess Andromeda, who has been chained by her father to a dashing ocean-front property as something of a sacrificial offering to ward off the sea creature Cetus from destroying the Kingdom (still dream of being a princess girls?). Perseus, hero that he is, slays Cetus, saves the lovely Andromeda and takes her for his bride. That’s the abridged version at any rate. Any questions? It’s all up there written in the stars:
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One of the great things about having a constellation named after you is that any interesting things that happen in the direction of your constellation might be named after you as well (special note to all the ambitious politicians out there: try to have a constellation named after you!). Perseus lucked out in this regard by having the comet known as Swift-Tuttle leave a trail of debris intersecting the orbit of our fair planet earth in just the right spot. Every year on its journey around our local star, the earth smashes through this dusty debris field, with sometimes dazzling results: as small bits of shed comet collide with the earth’s atmosphere they burn up, often to spectacular effect. To the casual observer on the ground, these incandescent, incinerating objects appear, for all the world, to be shooting stars. And because this particular cometary debris field always encounters the earth around the same time in its orbit, the shooting stars, or meteors as they are more properly known, always appear to have a common origin.
Thus, if you followed the path of every meteor in a particular shower and traced a line back to its origin, all of the lines would converge near a single point in the sky. This point is the radiant of the meteor shower. A time-lapse photo of the radiant would look something like this.
For the Perseids, the radiant lies very close to the constellation of Perseus, hence the eponymous name.

The simplest way to find the constellation of Perseus, and hence the radiant, is to find someone who knows where to look and have that person show you! Alas, simple is not always easy or convenient. In the alternative, a sky chart, like the one above, helps a lot. A larger scale map can be found here.
The great thing about the Perseids this year is that as long as you can find a cloud-free sky away from artificial light you really shouldn’t need a chart. Just find a comfortable place to lay back, open your eyes and look up. Often, the bright moon can wreak havoc on potential sky viewing, but this year the thin crescent moon sets in the west before Perseus rises in the north east. Perfect!
The peak viewing times this year will be Wednesday/Thursday (Aug 11/12) and Thursday/Friday (Aug 12/13) between midnight and the first light of dawn. With clear skies there may be 50 – 100 meteors an hour, though some meteor showers have produced over 400 an hour! A few years ago I was camping near Yosemite during the Perseids and slept out on the hard granite with my sleeping bag and pad but without a tent. Tired as I was from a long day of hiking, before my eyes closed I had counted over 50 shooting stars. So, have I “seen it raining fire in the sky?” That might be pushing it. But it was a very memorable experience, even if not exactly heroic.













