Meteor showers occur as Earth’s orbit of the Sun takes it through the stream of debris and dust left behind by comets. This debris hits our atmosphere and burns up, creating bright meteors that streak across the sky. In the case of the Orionids, the comet in question is the famous 1P/Halley.
While stargazers should not expect to see a return of Halley’s Comet in the sky until about 2061 (it last visited Earth in 1986), its dusty trail hits our planet’s atmosphere every October, most fully around the 21st and 22nd, making this the peak time to observe Orionids.
At its peak, the Orionid meteor shower offers a zenithal hourly rate (ZHR) of about 20-25.
The ZHR is a means of categorising the level of activity of a meteor shower and equates to how many meteors one might expect to see under perfect conditions when the radiant – the point from which the meteors seem to emanate – is directly overhead.
However, these numbers are guides and observers should in reality only expect to see a fraction of the ZHR.
While the Orionids’ ZHR might seem rather low in comparison to more spectacular showers of the year like August’s Perseids (up to 200) or the Geminids (120) in December, there is still a good chance of spotting a meteor or two during the period the Orionids are active.
How to see an Orionid
The Orionid meteor shower gets its name from the fact that its radiant is the constellation of Orion.
Locate Orion in the night sky and look away from the radiant, rather than directly at it, and you might be able to spot one or two flying in the opposite direction.
The best time to do your observing is between midnight and just before dawn, looking about two thirds up in the sky.
Use your naked eye, as binoculars or a telescope will merely narrow your field of vision, and find a place that is dark and away from the light pollution of cities and towns, provided it is safe to do so.
If you are lucky enough to live under dark skies and can observe from the comfort of your own garden, turn off the lights in your house so that they don’t spoil the view.
Wherever you do your observing, your eyes will take about 20 minutes or more to fully adapt to the dark and increase your chances of seeing a meteor.
The best advice is to simply look up!
Staring at the sky can be an awful strain on your neck during a long observing session, so reclining chairs are an advantage.
Considering we are approaching the colder months and observing involves a lot of standing or sitting still for long periods, be sure to wrap up warm and bring some snacks and drinks to keep your energy up.
Finally, meteor watching is best done with family and friends, as observing with companions makes those long observing sessions in the cold, early hours much more appealing!
If you manage to photograph any Orionid meteors this year, be sure to share with us via our Hotshots gallery or our Facebook and Twitter pages.