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Orionid meteors, debris from Comet Halley, visible tonight

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Tonight for October 20, 2014

The object in the picture isn’t a meteor. It’s the most famous of all comets, Comet Halley, the parent of the Orionid meteor shower. The Orionid meteors are expected to produce the greatest number of meteors tonight, especially in the dark hours before dawn tomorrow morning (Tuesday, October 21).

The meteors look like streaks of light in the night sky. They’re sometimes called shooting stars. Fortunately, in 2014, the slim waning crescent moon rising shortly before sunrise won’t obtrude on this year’s Orionid meteor shower.

October 2014 guide to the five visible planets

Comet Halley – the Orionid’s parent object, pictured at the top of this post – last visited Earth in 1986. As the comet moves through space, it leaves debris in its wake that strikes Earth’s atmosphere most fully around October 20-22. Around this time every year, Earth is more or less intersecting the comet’s orbit.

The cometary debris left behind by Comet Halley – bits of ice, dust and rubble – create the Orionid meteor shower.

Photo from Goldpaint Photography of the 2011 Orionid meteor shower at Middle Falls, near Mount Shasta, California. It’s a composite consisting of every meteor captured during the night and includes the Milky Way crashing into the illuminated falls. The image was Grand Prize Winner of Outdoor Photographer Magazine’s 3rd Annual Great Outdoors Photography Contest and published in their July 2012 issue. Notice there is more than one shower happening here. More from Goldpaint Photography here.

Fortunately, the thin waning crescent moon rising shortly before sunrise won't intrude on this year's Orionid meteor shower.

Fortunately, the thin waning crescent moon rising shortly before sunrise won’t intrude on this year’s Orionid meteor shower.

Orion meteor shower radiant in the constellation Orion

The best time to watch this shower will be between the hours of midnight and dawn – regardless of time zone. Oftentimes, 10 to 15 meteors per hour can be seen on a dark, moonless night. This year, the lunar crescent caps a night of meteor watching by rising in the east as darkness gives way to dawn. Good chance that you’ll see earthshine on the night side of the moon.

See Sirius, nighttime’s brightest star before dawn

If the meteors originate from Comet Halley, why are they called the Orionids? The answer is that meteors in annual showers are named for the point in our sky from which they appear to radiate. The radiant point for the Orionids is in the direction of the constellation Orion the Hunter. Hence the name Orionids.

Even one meteor can be a thrill. Bring along a blanket or lawn chair – after midnight or before dawn – and lie back comfortably while gazing upward. Although a somewhat modest shower, these swift-moving meteors are sometimes bright, occasionally leaving a persistent train – a glowing streak that lingers momentarily after the meteor has gone!

EarthSky’s meteor guide for 2014

How high up are meteors?

How do astronomers predict meteor showers?