Halley On Fire! Orionids Peak This Week

The annual Orionid meteor shower is active all week, peaking Friday morning October 21st. If you're up before dawn, you might just see these Halley's Comet castoffs come to life.

Spark of Halley in the Hunter

A bright Orionid makes a dash near the star Bellatrix in northern Orion during the 2014 shower.
Bob King

Christmas may come only once a year, but dust from Halley's Comet fires up the night sky twice: first in May during the Eta Aquarid meteor shower and this week when the Orionid shower peaks on the mornings of October 20th and 21st.

Meteor showers beautifully illustrate the more-bang-for-your-buck concept. A one-gram fragment of Halley slamming into Earth's atmosphere at a typical speed of around 148,000 mph (238,000 km/h) can produce a jaw-dropping fireball.

Nature ensures that even tiny rocks possess surprising power as long as they're moving fast. This energy of motion or kinetic energy is transferred to the atoms and molecules in the particle's path, briefly ionizing them. When the atoms return to their rest states, they emit light in the form of a meteor, or as my daughters would put it:  "Look, Daddy, a shooting star!"

Many shower meteoroids range in size from 1 mm to 1 cm (1/2 inch), and since most originate from comets, the material isn't rock solid but fluffy and friable. Perhaps you've witnessed a meteor that splits or break into pieces as it streaks through the air. When fragile bits strike the atmosphere at such high speeds, they might as well be hitting a brick wall. Pieces go flying.

Double Dusty Encounters

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. Perturbations by planets and the Sun have caused the particles to spread out into a ribbon centered on Halley's orbit. Halley's position is shown at perihelion in 1986 and in the current year, 2016. Not to scale.
Bob King

In May, the Earth crosses the outbound leg of Halley's orbit, and in October, the inbound leg. Halley returns to the Sun's vicinity every 76 years, gets roasted by sunlight, and makes a fresh deposit of motes, granules and fragments along its path, ensuring a supply of meteoroids for generations to come.

I love the ease of meteor watching. While it's important to be as comfortable as possible whenever you're out under the night sky, meteor showers provide an opportunity to spoil yourself with a few creature comforts. How about a nice reclining chair to pamper the back and a sleeping bag to stay cozy and warm? While you're at it, a mug of hot tea or coffee would fit right in along with a pair of earbuds and your favorite music. Or listen instead to the late leaves clattering in the breeze before November sets them free.

Orionid radiant near Betelgeuse

Orionid meteors, created by bits of debris from Halley's Comet, appear to radiate from a point near the upraised club or Orion. The shower is active through October 25th but reaches maximum on the 21st.
Sky & Telescope illustration

I normally make a mental tally of how many meteors I see and keep a camera by my side equipped with an intervalometer to maximize my chances of catching a meteor without having to attend to the shutter button. If you'd prefer a more rigorous approach, there's room for that, too. The American Meteor Society conducts a Visual Observing Program to keep track of changing activity in traditional showers as well as assist in the discovery of new ones. Use this basic form to record your meteor sightings.

Needles in a Starry Sky

Amateur astronomer Phil Hart of Australia composited a fine display of Orionids in 2011 into this stunning single image. All Orionid meteors, no matter where they appear in the sky, will point back to the radiant in northern Orion. 
Phil Hart

Where and When to Look

The Orionids start twitching as early as the first week in October but don't peak until Friday morning October 21st. Under a dark, moonless sky you'd typically catch about 20 meteors an hour radiating from the club of Orion high in the southern sky, but this year that number will be halved by the last-quarter Moon.

Don't let that stop you from taking time out this coming week to give Halley its due. Orionids are among the fastest of shower meteors; even if a few flash by, you'll be impressed by their swiftness. They normally peak when the radiant is highest, about an hour or two before the start of dawn (3:30–5:30 a.m.).

Make sure to face east or southwest, so you're not looking directly at the Moon. To do so would compromise your night vision and reduce the shower's visibility further. Then just settle in and watch the parade of winter stars overhead get peppered with pieces of Halley. If the sky is cloudy or you simply can't afford to lose the sleep, SLOOH will live broadcast the shower online starting at 8 p.m. EDT October 20th.

This year's relative dearth of meteors will help us better appreciate the 2017 show, when no Moon will trouble the sky. Good luck, and please stop back to share your observations!

13 thoughts on “Halley On Fire! Orionids Peak This Week

  1. Graham-Wolf

    Thanks for the timely reminder, Bob.
    Hopefully, the weather will oblige, down here at 46 South, New Zealand!

    Sad to report that Soviet Comet guru:- Klim Churyumov had a fatal stroke just a few days ago, whilst at a Conference near Kharkiv (check out the BAA Comet Section eulogy). Was in his late 70’s and highly regarded world-wide. Co discovered 67p (Rosetta Mission comet) amongst others. A mentor and hero to a whole generation of Ukranian astronomers:- particularly my T.A. colleague Alexander Baransky. Klim was also involved with the Vega-Halley Mission in the 1980’s. RIP to a really wonderful guy.

    Regards
    Graham W. Wolf (NZ)

    1. Bob KingBob King Post author

      You’re welcome Graham-Wolf. That is sad news about Klim. I thought I heard a rumor, so I appreciate the details you shared. How fortunate at least he got to experience the complete mission to his comet. (One of my very favorite comets by the way for sentimental reasons.)

  2. Graham-Wolf

    Hello again, Bob.
    Orionid season rather spoilt by overcast skies down here at 46 South, NZ. Did get a couple of hours observing in on Oct 21st, but counts were a little low, as waning Moon in the same quadrant (causing some lunar pollution). 1 pale yellow fireball seen (Mv -3)… a mild bonus.

    Bob:- 29p/SW1 may be about to outburst again.
    Has been steady at ~ Mv 17 all month (Seiichi Yoshida via Jean Paul Soulier), but has now climbed some 4Mv in last 2 days. I’ve clocked it as consistently fainter than Mv 15 all month, then Chris Wyatt at Walcha, NSW, logged it on Oct 23.41 UT as Mv 14.1, 0.3 arcmin coma, DC=8 (semi-stellar). A little later (Oct 23.46 UT, in barely 1 hr of clear skies between overcasts) I got Mv 14.0, 0.5 arcmin coma, DC=6 (Green island Guest Observatory (G.G.O.), Dunedin, NZ. Chris again logged the following at Oct 24.42 UT:- Mv 13.8, 0.4 arcmin coma, DC=5/6.

    Chris was using a 25cm f5 GSO Research-Grade dielectric-coated Dob at 167x. I was using a loaned 30cm equivalent of the same instrument, at 400x with SV15 “Superview” and Barlow projection (10.4 arcmin FOV). My Mlim is Mv15.0 to 15.4 within 30 deg of the Zenith, at 400x. I used an AAVSO-VSP custom generated chart (2df Mlim 15, centred near Nunki in Sgr), but you may prefer other options. Is this latest “effort” by 29p/SW1 a “damp squib”, or the precursor to another “eruption”? We should all find out in a few days! Been personally rained out last day and a half. Electrical storms and hail due here, in another 3 to 4 hours. Good hunting, Bob!

    Graham W. Wolf, NZ

    1. Bob KingBob King Post author

      Graham-Wolf,
      That small coma along with a DC=6 sounds like a possible minor eruption. Do let me and our other readers know if it spikes further. Let’s hope so. Thanks for updating!

  3. Graham-Wolf

    Totally agreed, Bob.
    29p/SW1 appears to have had a minor eruption, for now.
    Back home during weekend, after being away for several days far North, for an AGM.
    Had a quick look at 29p, last 2 nights in a row ~ local midnight at 46 South, NZ. Mvs seem to be in the high 12’s, so maybe, this was a damp squib after all. Gonzalez reported it on Oct 26.80 UT at Mv 12.7 0.2 arcmin coma, DC7 (LIADA Website). I’m praying for a bigger spike in about a week or so. We’ll see!
    Regards from Graham Wolf:- 46 South, NZ.

  4. Graham-Wolf

    Hi Bob.
    Another update on 29p SW1.

    Chris Wyatt at Walcha, NSW; and I (Green Island Guest Observatory (G.G.O.) NZ) both observed the comet. Chris used a 25cm f5 Dob, myself a borrowed 30cm f5 Dob… both with enhanced dielectric coatings. Chris got Nov 01.42 UT Mv 12.9, 0.5 arcmin coma, DC2, I got Nov 01.45 UT Mv 12.8, 0.7 arcmin coma, DC2. He got Mv 13.0 the night before (Oct 31st) Chris used 83x, I used 300x. My ZLM at the G.G.O. was + 6.0. 29p seems to hovering in the high 12’s and has yet to spike again. Let’s wait and see if it goes “gang-busters”, soon…

    Currently rebuilding and tweaking a trashed 2nd hand 12cm equatorial Newt. OTA is fine… cleaned the optics, now working on the mechanicals (in the daytime, of course). Previous owner wrote it off. It’s getting a “resuscitation” from me. It’ll be ready to attack the cosmos soon,
    Graham Wolf at 46 South, NZ

    1. Bob KingBob King Post author

      Graham-Wolf,
      Although I see the coma’s expanding and the comet no doubt beginning to fade, do let us know if 29P breaks 12th magnitude again. Thanks!

  5. Graham-Wolf

    Hi Bob

    Chris Wyatt just e-reported in a few short hrs ago. He travelled south, and used the 35cm SCT at Armidale Observatory, at Armidale NSW. Here’s his latest data. Nov 2.48UT, Mv 13.0, 0.8 arcmin coma, DC2/3, Mag=122x. I was clouded out last night to ~ 2am local time, today, and was frankly too “shattered” to get out of bed. We can safely assume that 29p is currently holding steady at ~ Mv 13. When it does goes off, we’ll all soon know!! Keep up the great work, Bob.
    Graham Wolf at 46 South, NZ.

  6. Graham-Wolf

    Hello Bob.

    Seiichi Yoshida (Japan) reports 29p at Mv 12.3 on Nov 4.40UT, with his 40cm Dob at 144x. I got a similar reading, the following night ~ local midnight. Tried this morning at ~ 2am NZDT, but the Moon was at First Quarter and still high enough to pollute the adjacent quadrant, down to a ZLM ~ 4. We’ll have to wait another fortnight, for the Last Quarter Moon to rise in the morning hours, to visually re-acquire the comet. Regards from 46South, NZ. Graham Wolf.

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