RSS
Home
Halley's Comet Returns...sort of
Print
Email
RSS
Subscribe
For anyone interested in watching meteor showers, the Orionids may not be the strongest shower of the year, but they have an interesting lineage: they are dust particles thrown off by the famous Halley's Comet.
The Orionids emanate from the constellation Orion. They were first discovered by E. C. Herrick (Connecticut, USA) in 1839. Although he then noted activity was present from October 8 to 15, we now know that meteors from this shower can be seen throughout the month, with the actual peak of activity occurring on October 21.
This meteor shower became one of the most studied annual showers after the 1890s and one of the most intriguing early findings was the variability of the activity from one year to the next. The peak rates can be as little as 10 per hour or as high as 35 per hour. Even more interesting is that sometimes there is one distinct peak lasting a few hours, sometimes as many as three distinct peaks, and, on occasion, the shower will reach its peak and hold high rates for as long as three days! Because of this, astronomers generally recognize that the Orionids should be watched on the mornings of October 18 to 23.
The astronomer C. P. Olivier (Virginia, USA) noted in 1911 that the orbit of the Orionids was quite similar to the orbit of the Eta Aquarid meteor shower. This was an intriguing idea because it had already been determined that the latter shower was produced by the famous Halley's Comet. A debate followed because the orbit of Halley's Comet did not come close enough to Earth in October to produce such a strong shower. The debate continued for over 7 decades. Finally, in 1983, B. A. McIntosh (Ottawa, Canada) and A. Hajduk (Bratislava, Czechoslovakia) noted, "the meteoroids simply exist in orbits where the comet was many revolutions ago." Indeed, the orbit of the Orionids almost perfectly matched the orbit that Halley's Comet moved in about 2300 years ago.
The Orionids are a morning meteor shower, as the area of the sky where they emanate does not rise above the horizon until after midnight. The best time to observe will be from 1:00 a.m. until the beginning of morning twilight. There are some minor meteor showers producing activity at the same time as the Orionids, but the Orionids will generally be producing the fastest meteors. To enjoy the Orionids to the fullest, it is best to be as far from city lights as possible. The best equipment to use is a lawn chair that flattens out to allow a view of as much of the sky as possible. Don't stare at one area of the sky, but let your eyes drift about. Some of the brightest stars in the sky are visible at this time of the morning during October. Enjoy!
