The October Draconids meteor shower, also referred to as the Giacobinids, have gained notoriety in the past due to their occasional outbursts that have produced spectacular showers. Though typically reaching a maximum rate of only one to two meteors per hour, in the past the Draconids have produced showers with Zenith hourly rates of thousands of meteorites per hour.
The Draconids occur each year during October 6th through October 10th. The peak date of the shower generally falls on the 9th or 10th, close to the end of Earth’s encounter with the debris stream. During this peak time observers in the northern hemisphere may see one to two streaks per hour, with no more than three or four per hour at best. Due to the location of the stream, the Draconids shower is not easily observed in the southern hemisphere, as it only peaks the southern horizon in the very early morning twilight for a short time making viewing difficult. In the northern hemisphere, the best time for viewing the shower is also in the early morning hours, between about 4 am and sunrise. The radiant of the shower is the constellation of Draco, which lies north of Ursa Major, the Big Dipper.
The source of the Draconids meteor shower is the comet Giacobini-Zinner, or 21P/Giacobini-Zinner which was discovered at the turn of the 21st century. The shower itself was the result of speculation on the part of astronomer M. Davidson, who believed that the Giacobini-Zinner comet could likely produce a meteor shower during some time in October. Davidson was correct in his theories and the Draconids shower was discovered, though at it’s discovery time it remained a minor and irregular shower at best.
However, in 1933 when the comet Giacobini-Zinner made it’s perihelion orbit, the shower that the Earth experience produced a spectacular cosmic show. The sky over Europe was lit up with thousands of meteors streaking across the sky, all coming from the same radiant. According to reports of astronomers, the 1933 Draconids meteor shower produced a staggering 100 meteors per minute.
For some years after the 1933 shower, the Draconids returned to their regular rate of just a few meteors per hour. Then, in 1946 as the Giacobini-Zinner comet made yet another perihelion orbit the Draconids once again sprang to life with another meteor shower that was this time more predominantly visible over the Americas. From Canada to South America, the night sky was aglow with up to 3,000 meteors per hour.
These two showers are the most notable events associated with the Draconids shower. Each time the Giacobini-Zinner comet makes it’s perihelion orbit (approximately every six years) astronomers wonder if we will encounter another massive shower as those seen in the past. However, it seems as though making such a prediction has proven to be difficult.