The annual Orionids meteor shower peaks this year on October 21st and the prospects are favourable as the three-day-old Moon will not interfere. Generally regarded as a strong shower, the Orionids is active between October 2nd and November 7th, with most meteors visible a few days before, during and after peak day. In the past rates of up to 70 meteors per hour have been observed, but currently the shower is not so active. A figure between 20 and 25 is now the norm.
The Orionids parent object is the most famous comet of all, Halley (1P/Halley). Of the two meteor showers associated with Halley, the Orionids is the more prolific. The other, weaker shower, is the Eta Aquariids (Eta Aquarids), which occurs during May. Although Halley is now in the outer Solar System and will not return to Earth until 2061, it's worth remembering that every Orionids meteor is a small part of the famous comet streaking through and burning up in the atmosphere.
The radiant of the Orionids is located in the northeastern part of Orion, close to the Gemini border. Since Orion straddles the celestial equator, it's one of the few annual showers that can be seen from all inhabited locations on Earth.
As previously mentioned, this is a good year as the three-day-old Moon won't interfere. The shower is also reliable and produces bright fast meteors that streak through the sky as they hit the atmosphere at 235,000 kilometres/hour (145,000 miles/hour). As with all annual meteors showers, it's best not to look directly at the radiant itself but scan a large area of sky surrounding it.
Orionids Data Table 2017
|Meteor shower name||Orionids|
|Meteor shower abbreviation||ORI|
|Activity||October 2nd -> November 7th|
|Peak Date||October 21st|
|RA (J2000)||6hr 20m|
|ZHR||20 to 25 (can vary between 20 and 70)|
|Notes||Most prolific meteor shower associated with Halley's Comet|
Comet 1P/Halley Data Table (at epoch February 17th, 1994)
|Classification||Halley-type comet (NEO)|
|Discoverer||Prehistoric, Edmond Halley first recognised the periodicity|
|Semi-major axis (AU)||17.8341|
|Orbital period (years)||75.3175|
|Longitude of ascending node (degrees)||58.4201|
|Last perihelion||February 9th, 1986|
|Next perihelion||July 28th, 2061|
|Notes||Halley's comet, the most famous of all comets|