See Meteors From Halley’s Comet, Orionids Peak Monday Night

The annual Orionid meteor shower peaks overnight Monday, Oct. 21 when bits of Halley’s Comet will stream from a point above the figure of Orion the Hunter called the radiant. The map depicts the view around 5 a.m. local time. Stellarium

I’m embarrassed to admit this but I used to ignore the Orionids because I considered it a minor shower. But that changed several years back when I finally gave the shower its due. While no August Perseids, the Orionids were a delight. The flashed by so quickly I could hardly believe my eyes.

At peak, which will happen Monday night through Tuesday dawn (Oct. 21-22), you’d expect to see 15-20 meteors per hour under a dark, moonless sky. The real number will be a little lower because a somewhat-less-than-half-moon will shine off to the east in Cancer the Crab. Have a need for speed? What really sets the Orionids apart is their swiftness. These piercing javelins of light shoot across the sky at around 150,000 miles per hour or 67 km / sec, second only to the November’s Leonid meteor shower.

Orionids hail from Halley’s Comet. When Earth encounters the inbound leg of the comet’s orbit, we plow through the comet’s dust trail. Motes, particles, and tiny pebbles strike the atmosphere at high speed, flare, and create a shower of meteors. Halley’s position is shown at perihelion in 1986 and in the current year, 2019. Not to scale. Bob King

That’s why I finally bought into the Orionids. Although I’ve typically seen about a dozen per hour their speed amazes. That and the fact you’re looking at bits and pieces of Halley’s Comet further elevates the shower into something special. Each year, Earth crosses the orbit of the famous comet, first in May and again in late October. Scattered along the orbit like leaves on woodland trail are small fragments of Halley’s, boiled off during each close pass of the sun. The debris spreads out over time, so the Earth takes time to cross the entire stream. For that reason the Orionids last about a week, but the peak times, when we pass through the densest part of cloud, are the mornings of Oct. 21 and 22.

In May, the pieces radiate from a point in the constellation Aquarius and make the Eta Aquarid meteor shower, while in October they tear out of Orion. The Orionid radiant climbs above the southeastern horizon by 11:00 p.m. local time this week, so it’s possible to see a little of the shower in a dark sky. But the moon rises around 11:30, so I’d suggest waiting until between 2 a.m. and 6 a.m. (start of dawn) when the radiant is highest.

One Orionid (top) and a possible second flash across the scene that includes the Milky Way and the constellation Orion (bottom) photographed on Oct. 22, 2007. Orionids can appear anywhere in the sky; each trail points back to the radiant. Brocken Inaglory / CC BY-SA 3.0

The forecast for my region isn’t good, but if it were to clear I would be outside from 4-6 a.m. Tuesday morning when the radiant stands highest in the southern sky. I like a reclining lawn chair for comfort and would set it up to face south or southwest, away from the direction of the moon. Moongazing will hurt your night-vision and make it harder to see fainter meteors, but at least we only have to deal with a thick crescent. Full moons can put a big hurt in a meteor shower as it will for the Geminids in December.

Although the Orionids have been known to surprise with rates more than double the normal, expect a dozen over an hour or so. I think you’ll find it time well spent, plus you’ll get to see Orion stride majestically across the south the way it appears in January but without the bitter cold. If you have binoculars take a few minutes to observe the moon. It’s in an ideal phase for seeing craters along its upper right side called the terminator. Before full moon the terminator defines the line of advancing sunrise across the lunar surface; after full phase it becomes the line of sunset.

Meteor showers are fun and easy to watch. If you add a blanket to stay warm under and a hot cup of coffee or hot chocolate it’s practically a picnic!

1 Response

  1. Edward M Boll

    In what some scholars ate now saying is the oldest written Bible recording perhaps over 4000 years ago, we have in the book of Job, the constellation Orion mentioned in chapter 9 and 38.

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