Tonight – October 8, 2015 – the constellation Draco the Dragon will be spitting out meteors, also known as shooting stars. The Draconid shower is predicted to produce the greatest number of meteors on the night of October 8. The next night, October 9, might feature some meteors, too.
Most meteor showers are best after midnight, but this shower is different. Watch for them first thing at nightfall. Fortunately, the waning crescent moon won’t interfere with this year’s Draconid meteor display. This shower is best viewed in the evening, but the moon won’t rise until the wee hours of the mornings on October 9 and 10.
More about the Draconids below, but first a word about the October 9 display of the moon and Venus.
Our sky chart above shows the moon and planets as seen from North America, but if you’re in Australia – although you won’t see many meteors in the far-northern Draconid meteor display – you do have a chance to watch the lunar occultation of Venus on the morning of October 9. If that’s you, click here or here for more details. The latter link lists the times off the occultation in Universal Time, so click here to know how many hours to add to Universal Time for your Australian time zone.
Now back to the meteor shower! If you live at middle and far northern latitudes anywhere around the globe, this shower is well worth a try. Unlike many major showers, the radiant for the Draconids is highest up at nightfall, so it’s best to watch for these meteors as soon as darkness falls, not in the wee hours before dawn.
Here’s the best way to watch. Spend an hour or more under a dark and open sky, lying down and with your feet pointing northward. Oftentimes, this hard-to-predict shower doesn’t offer much more than a handful of languid meteors per hour.
But watch out if the Dragon awakes!
The Draconid meteor shower produced awesome meteor displays in 1933 and 1946, with thousands of meteors per hour seen in those years. Four years ago – in October 2011 – people around the globe saw an elevated number of Draconid meteors, despite a bright moon that night. European observers saw over 600 meteors per hour in 2011.
As far as we know, nobody is calling for the Draconid meteor shower to burst into storm in 2015. But you never know for sure with the Draconids, so it’s worth watching out for on the moonless evening of October 8. Just keep in mind that meteor showers are notorious for defying predictions, either surpassing or falling shy of expectation.
The only way to know for sure is to try to watch the shower.
Once again, watch at nightfall and early evening because that’s when the radiant point for the Draconid shower is highest in the nighttime sky. We emphasize it, because most meteor showers are best after midnight … but not this one.
Most meteor showers are named for the constellation from which the meteors radiate on the sky’s dome. The Draconids, however, are sometimes also called the Giacobinids, to honor the man who first sighted the comet that spawned this meteor shower. Michel Giacobini discovered this comet on December 20, 1900. Another sighting in 1913 added the name Zinner to that of the comet, which thus became 21P Giacobini-Zinner.
Giacobini-Zinner is a periodic comet, which returns every 6 years and 4 months. Tracking this comet, and noting this October meteor shower, helped astronomers figure out how to predict meteor showers in 1915.
Now let’s consider the great Draconid/Giacobinid meteor storms of 1933 and 1946, and that of 2011, when observers in Europe saw over 600 Draconid meteors per hour. Why was the meteor shower so good in 2011? Why do we see more meteors in some years than in others?
The answer is that Comet Giacobini-Zinner was at perihelion – closest to the sun – in 2011. Meteors are debris from comets, so when a parent comet is nearby, a good meteor shower is possible.
It doesn’t always happen, though. The comet returned in 1998, and the Draconids did pick up that year, but only to a rate of about 100 per hour.
That’s the thing about meteor showers. They are part of nature and not entirely predictable. Under normal conditions, when astronomers speak of a meteor shower peaking, it’s similar to a weather forecaster saying:
The heaviest rain/snow is predicted for 9 p.m.
That prediction isn’t a certainty. It’s more like an educated guess, and it might not come to pass. Or it might happen for people in some parts of the weatherperson’s viewing area, but not in others. It’s a good analogy to the 2011 Draconids, which were best seen over Europe but less good, for example, over North America.
Nature is always unpredictable to a degree. So what does peak night really mean for watching a meteor shower? Generally speaking, it means the rate of meteors falling that night is likely to be higher than on other nights.
Clouded out for the Draconids? Didn’t see a thing? For tips on viewing meteor showers for the remainder of this year, read this EarthSky article.
And for a taste of history related to this shower, go to the Astronomy Abstract Service from the Smithsonian and NASA and find a 1934 article called “The Meteors from Giacobini’s Comet” by C.C. Wylie. It’s an account of the famed meteor storm of 1933.
Bottom line: In 2015, the Draconid meteor shower – also called the Giacobinids – peak on the night of October 8. The night of October 9 might feature meteors, too. The radiant is highest in the evening hours, so no need to wait until after midnight. Find a dark, country sky and as much open sky as possible. Lie down on a reclining chair and look upward, starting at nightfall. How many Draconid meteors can you count in the moon-free skies these next few evenings? No one expects a Draconid storm this year, but it’s fun to wait and see.