October’s Draconid meteor shower – sometimes called the Giacobinids – is gearing up. In 2018, a new moon on October 9 means no moonlight to drown the meteors in its glare. There’s a second meteor shower – the South Taurids – also rambling along now, and you might catch some of those meteors, too. The Draconid shower is usually a sleeper, rarely offering any more than five 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. European observers saw over 600 meteors per hour in 2011.
Will 2018’s Draconid shower be spectacular?
Meteors in annual showers tend to storm when their parent comets are nearby. In 2018, the Draconids’ parent – Comet 21P/Giacobini-Zinner – reached its perihelion or closest point to the sun on September 10. That’s close! Is it close enough? Many are saying it’s possible we’ll see elevated levels of Draconids this year.
Or, it’s possible we won’t.
Here’s what Robert Lunsford of the American Meteor Society said in its meteor outlook for October 6-12:
Experts have studied the conditions for this year and have come to the conclusion that nothing exceptional will occur [for the Draconids in 2018]. Still, no one is 100 percent certain of this so I would advise all observers with clear skies on the evening of October 8 to watch for at least an hour after the sky becomes sufficiently dark. Any notable activity would most likely occur between 23:00 UTC on October 8 to 01:00 UTC on October 9 [translate UTC to your time]. These times favor the Atlantic area including western Europe, northwestern Africa, northeastern South America, and eastern North America. For those located in the Eastern time zone of North America, this timing is equivalent 7 p.m. to 9 p.m. EDT.
The Draconid shower is active between October 6 and 10. As noted above, the best evening to watch is likely October 8; try the evenings of October 7 and 9 also. Notice the word evening. This is one shower you don’t have to stay up late to see. Start watching first thing at nightfall. Be sure to watch under a dark, open, country sky.
How many Draconids will you see? In general, the Draconids aren’t a rich shower, unless their parent comet is nearby. They typically produce only about five meteors per hour.
This annual meteor shower happens when Earth in its orbit crosses the orbital path of Comet 21P/Giacobini-Zinner. Debris left behind by this comet collides with the Earth’s upper atmosphere, to burn up as Draconid meteors. This comet has an orbital period of about 6.6 years. It’s about six times more distant at its farthest point from the sun than at its nearest point. At aphelion – its most distant point – it’s farther out than the planet Jupiter. At perihelion – its closest point to the sun – it’s about the Earth’s distance from the sun.
On rare occasions – when the peak of the shower coincides with the comet’s perihelion – this shower has been known to rain down hundreds or even thousands of meteors in an hour.
The last perihelion of the comet was September 10, 2018. On that same night, Comet 21P/Giacobini-Zinner came closer to Earth than it had in 72 years. We posted best pics of the comet as it swept safely past, three weeks ago.
That was fun … but does that recent perihelion of the comet mean the Draconids will be spectacular in 2018?
No one knows.
For people who enjoy meteor showers, that’s part of the fun! As a wise person once said, meteor showers are like fishing. You go, and sometimes you catch something.
Where is the radiant point of the Draconid shower? The Draconids are best in the evening, instead of before dawn, because the winged Dragon, the shower’s radiant point, flies highest in the sky at nightfall.
As night passes – no matter where you are on Earth – the radiant point sinks lower in your sky.
The Draconid meteors, when traced backward, radiate from the head of Draco the Dragon, near the stars Eltanin and Rastaban.
You don’t have to locate Draco the Dragon to watch the Draconids. These meteors fly every which way through the starry sky. But finding Draco is fun, and relatively easy.
The Draconids have a rich history. Most meteors in annual showers are named for the constellation from which they appear to radiate, in this case Draco the Dragon.
Draco’s meteors, however, defy convention by sometimes also being called the Giacobinids, to honor the role this comet played in the history of astronomers’ understanding of what meteors actually are.
Michel Giacobini discovered this comet on December 20, 1900, so the comet received his name. Another sighting in 1913 added Zinner to the comet’s name, which thus became 21P/Giacobini-Zinner. Astronomers in the early 20th century thought that meteors and comets were related, so of course they tried to link various comets to the spectacular showers of meteors that sometimes rain down in Earth’s sky.
Comet 21P/Giacobini-Zinner was a particularly tempting object about which to make predictions. Remember, it returns every six years, and its closest point to the sun is about the same as Earth’s distance.
What’s more, Comet Giacobini-Zinner did not disappoint the astronomers.
The Draconid meteor shower produced awesome meteor displays in 1933 and 1946, with thousands of meteors per hour seen in those years.
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.
The relationship between 21P/Giacobini-Zinner and its meteors – so studied and discussed among professional astronomers in the early 20th century – probably explains why the Draconid meteor shower sometimes goes by the name Giacobinids.
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.
Can you see the Draconids from the Southern Hemisphere? It’s possible. But if you’re so far south that the radiant point in the constellation Draco doesn’t rise above your horizon, or rises only briefly, you won’t catch many.
As seen from the Southern Hemisphere, you would have to be rather close to the equator in order to see Draco’s stars. Suppose you live in northern Australia – say Darwin, in northern Australia – which is at 12 degrees south latitude. If so, you’d be able to see the stars Rastaban and Eltanin very close to your north-northwest horizon at nightfall in early October (given an unobstructed northern horizon). These stars would set at fairly early evening, and you wouldn’t see the head of Draco again until nightfall the following evening.
Why early evening? It’s because, no matter where you live worldwide, the head of Draco reaches upper transit (highest point in your sky) at around 5 p.m. local time in early October.
Thus from latitudes in the Southern Hemisphere – even those as far north as northern Australia – you would have a very narrow window for seeing meteors. If you’re in the Southern Hemisphere, and you’re really wanting to see a Draconid, try looking as soon as it gets really dark on October 7 and 8, and don’t expect much.
Bottom line: In 2018, the Draconid meteor shower – also called the Giacobinids – will probably produce the most meteors on the evening of October 8. Try the evenings of October 7 and 9 also. Don’t wait until after midnight. Watch as soon as it gets dark outside. Find a dark country sky and as much open sky as possible.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.