The Draconid meteor shower will again be visible tonight in the northern hemisphere.
The meteor shower occurs when dust from Comet Giacobini-Zinner enters Earth’s atmosphere and ionizes, creating a “shooting star” look.
The meteors appear to come out of the constellation Draco (the dragon) and the flurry of them will appear highest in the sky shortly after sunset. As night advances the spectacle drops below the horizon.
The Draconids can be unpredictable in their intensity. Astronomers have not predicted a noteworthy display from the Draconids this year, but in some years the number of meteors is impressive. In 2011 more than 600 per hour were visible.
The reason for 2011’s display was that Comet Giacobini-Zimmer was at the perihelion of its orbit around the sun.
Earth’s moon is not likely to be much of an impediment to viewing the meteors, as it is in waxing crescent phase now.
Observers will have the best opportunity to see meteors if they choose a viewing location far from city lights.
Graphic courtesy EarthSky.org.
If you can get outside and beneath a dark night sky in the wee hours of Sunday morning, the reward might be a chance to see remnants of Halley’s comet.
The annual Orionid meteor shower will peak at 10 pm MDT, but the best viewing of the spectacle will happen in the hours between midnight on Saturday night and dawn on Sunday.
“Halley’s Comet is very much alive and well,” Dr. William J. Cooke, the lead scientist at NASA’s Meteoroid Environment Office, said. “Like all comets, it sheds debris as it approaches the Sun. Ice sublimates to gas, which frees bits of rock to escape the comet’s surface and form streams of material in its wake. Over time, some of these particles will collide with Earth and produce the Orion meteor shower we see now.”
Halley’s comet, which has been observed by humans since 240 BC, was last visible in 1986. It won’t be seen again until 2061.
There’s a bonus to staying up late or waking up before dawn, too. You should be able to see Jupiter to the northeast of Orion. The solar system’s largest planet will be brighter than Sirius.
If you are out close to dawn you can look for Venus in the eastern sky. Earth’s neighbor will be even brighter than Jupiter.
One fun way to enjoy the Orionid meteor shower is to locate the region of the heavens that appears to be its source. You don’t have to do this to see the “shooting stars,” though, since they will appear throughout the sky.
If you want to find the constellation that looks like the fountainhead of the meteors, begin by locating Sirius. Sirius is the brightest star in the night sky and will be to the southwest of the meteor shower’s namesake, Orion.
Once you find Orion, locate the three stars in the middle of the image. They make up Orion’s Belt. The meteors will seem to come from the rectangle that surrounds this region of the constellation.
The Orionids are somewhat unusual in that the number of meteors visible each year is fairly constant.
“This is because the Orionid stream is fairly wide (10 million miles or so) and not concentrated like the Leonids or Perseids,” Cooke said. “Because it is wide, the material is more evenly distributed, which explains the steady rates.”
Cooke noted that the rate of meteors can vary by factor of 3.
“The low is 20 per hour, and rates over 60 per hour have also been observed,” he said. “The past few years have seen Orionid rates on the higher side.”
You can continue to see a dwindling array of shooting stars in the early morning sky through Nov. 14. The Orionids start to appear in early October.
The next significant meteor shower happens in December. The Geminids, which peak around Dec. 12, are even more spectacular than the Orionids.
“It has the best rates of any annual shower, usually topping 100 per hour,” Cooke said.
For night sky enthusiasts, 2012 promises to start with a shower. A meteor shower, that is.
The Quadrantids meteor shower will peak on Tuesday night. The peak is short, with viewers able to see as many as 130 meteors flashing across the sky.
A lesser number, perhaps as many as 50 in an hour, may be seen until sometime shortly before dawn on Wednesday morning.
Viewers should look for a place far from city lights to observe the phenomenon, which appears to the eye to originate in the constellation Bootes.
In fact, the Quadrantids come from an asteroid called 2003 EH1, which scientists think is part of a comet that broke apart in the late fifteenth century.
The meteor shower gets its name from a defunct constellation called Quadrans Muralis, which used to show up on star maps between Bootes, Draco, Hercules, and Ursa Major. Quadrans Muralis ceased to be a recognized constellation in 1922, when the International Astronomical Union adopted the modern list of 88 constellations.
The Quadrantids are not visible in the southern hemisphere, and the weather during the northern winter can make it difficult for viewers to see them.
For this reason NASA’s Ames Research Center conducted an airborne mission to observe the shower in January 2008. Scientists flew from San Jose, California over the North Pole and back in a Gulfstream jet to determine when the Quadrantids peak and how the meteors disperse.