Orionids Peak Sunday, Oct. 21, Night to Pre-Dawn Monday, Oct. 22

Summary: The 2018 Orionids peak Sunday, Oct. 21, night to pre-dawn Monday, Oct. 22, in an annual display that generally begins Oct. 15 and ends around Oct. 29.

green and red Orionid shooting star; Monday, Oct. 22, 2007: Brocken Inaglory, CC BY SA 3.0 Unported, via Wikimedia Commons

The 2018 Orionids peak Sunday, Oct. 21, night to pre-dawn Monday, Oct. 22, in an annual display of shooting stars that usually runs from around Oct. 15 to around Oct. 29.

The American Meteor Society describes Orionid showers as swift. The Society clocks Orionid shooting star velocity at 41 miles per second (67 kilometers per second).

The Orionids normally produce peak rates of 20 to 25 shooting stars per hour. Exceptional years yield Perseid-style rates of 50 to 75 per hour.

NASA meteor expert Bill Cooke predicts a display “at the smaller end of the scale” per hour during the 2018 Orionids’ peak. He gives a visibility estimate of 15 to 20 meteors per hour for Space.com contributor Elizabeth Howell.

“The moon is going to mess with you,” Cooke tells Space.com.

EarthSky Tonight’s lead writer, Bruce McClure notes competing glare from the moon’s waxing gibbous phase during peak. Surface visibility of the lunar disk during the Orionid peak is estimated at 90 percent.

McClure suggests Friday night, Oct. 19, to pre-dawn Saturday, Oct. 20, as a less-moonlit date. Surface visibility is estimated at 75 percent for that date.

Meteor showers tend to exhibit buildups that precede and/or follow peaks. McClure shares that the Orionid peak’s broadness will inspire aficionados to survey the sky for three nights, from Friday night, Oct. 19, to dawn Saturday, Oct. 20; Saturday night, Oct. 20, to dawn, Sunday, Oct. 21; peak night, Sunday, Oct. 21, to pre-dawn Monday, Oct. 22.

American amateur astronomer Gary W. Kronk advises observers at mid-northern latitudes to look to the east-southeast beginning around 1 a.m. local time. Observers at mid-southern latitudes should look to the northeast around 2 a.m. local time.

The Orionid meteor shower derives its name from its apparent point of origin in Orion the Hunter constellation. Robert Lunsford, American Meteor Society’s weekly Meteor Activity Outlook columnist, identifies the radiant as 3 degrees northwest of Nu Orionis (ν Orionis; Nu Ori, ν Ori) and 9 degrees due north of Alpha Orionis (α Orionis; Alpha Ori, α Ori) in northeastern Orion. Alpha Orionis is Orion the Hunter’s second brightest star. The red supergiant’s traditional name is Betelgeuse (Arabic: yad al-jauza, “hand of al-Jauza [the Central One]”).

The Orionids’ parent body is Halley’s Comet. Officially designated as 1P/Halley, Comet Halley qualifies as a short-period comet with an orbital period of less than 200 years. NASA’s Jet Propulsion Laboratory (JPL) lists Comet Halley’s orbital period as 27,509.1290731861 days, or 75.32 years.

The Jet Propulsion Laboratory’s orbital diagram for Halley’s Comet places the famous comet at an Earth distance of 34.872 astronomical units (au) and a sun distance of 34.695 au at 23:00 (11 p.m.) Coordinated Universal Time (7 p.m. Eastern Daylight Time), Sunday, Oct. 21. One astronomical unit roughly equates to the distance from Earth to sun, with an exact length of 149,597,870,700 meters (about 150 million kilometers; 93 million miles). Halley’s Comet will be positioned in the outer solar system, beyond the orbit of Uranus.

The Orionids occur as the second of two annual meteor showers associated with Halley’s Comet. The Eta Aquarids appear as the year’s first Halley’s Comet-induced meteor shower. The Eta Aquarids usually display between mid-late April and mid-late May, from around April 19 to around May 28.

The Eta Aquarid meteor shower’s radiant is near Eta Aquarii (η Aqr, η Aquarii) in Aquarius the Cup Bearer, or Water Carrier, constellation. Eridanus the River, Cetus the Whale and Pisces the Fishes constellations separate Aquarius from Orion.

Amateur astronomer Edward Claudius Herrick (Feb. 24, 1811-June 11, 1862) of New Haven, Connecticut, is credited with discovery of the Orionids. He noted in The American Journal of Science and Arts for January 1839: “There are other seasons in the year at which meteors may possibly be found unusually numerous: some of these are, -- Oct. 8-15, June 10-20 . . . . Of this list, the two first appear the most worthy of attention.”

English astronomer Alexander Stewart Herschel (Feb. 5, 1836-June 18, 1907) is credited with providing the first precise observation of the Orionids on Oct. 18, 1864. He confirmed the shower’s Orion radiant Oct. 20, 1865.

The takeaways for the Globe at Night 2018 second Perseus and Grus campaigns, which simultaneously run from Thursday, Nov. 29, through Saturday, Dec. 8, are that both campaigns close as the second of two 2018 Hero and Crane campaigns and that their completion signals the end of Globe at Night’s 2018 campaigns in the Northern Hemisphere and the Southern Hemisphere.

orbital diagram for 1P/Halley, Sunday, Oct. 21, at 23:00 UTC (7 p.m. EDT): JPL’s Solar System Dynamics, May be used for any purpose without prior permission, via NASA Jet Propulsion Laboratory

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

green and red Orionid shooting star; Monday, Oct. 22, 2007: Brocken Inaglory, CC BY SA 3.0 Unported, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Orionid_meteor.jpg

orbital diagram for 1P/Halley, Sunday, Oct. 21, at 23:00 UTC (7 p.m. EDT): JPL’s Solar System Dynamics, May be used for any purpose without prior permission, via NASA Jet Propulsion Laboratory @ https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1P;old=0;orb=1;cov=0;log=0;cad=0#orb

For further information:

American Meteor Society. “Orionids.” American Meteor Society > Meteor Shower Calendar.
Available @ https://www.amsmeteors.org/meteor-showers/meteor-shower-calendar/

Herrick, Edward C. (Claudius). “Observations on the Shooting Stars of August 9th and 10th, 1840: Some Other Meteoric Periods.” American Journal of Science and Arts, vol. XXXIX (October 1840), no. II: 334. New Haven CT: G.L. Hamlen, 1839.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/30954800

Herrick, Edward C. (Claudius). “Report on the Shooting Stars of Dec. 7, 1838, With Remarks on Shooting Stars in General: There are other seasons in the year . . .” American Journal of Science and Arts, vol. XXXV (January 1839), no. II: 366. New Haven CT: B.L. Hamlen, 1839.
Available via Biodiversity Heritage Library @ https:// biodiversitylibrary.org/page/15636334

Howell, Elizabeth. “Orionid Meteor Shower 2018: When, Where & How to See It.” Space.com > Skywatching. Jan. 23, 2018.
Available @ https://www.space.com/34373-orionid-meteor-shower-guide.html

Jenniskens, Peter. Meteor Showers and Their Parent Comets. Cambridge, England: Cambridge University Press, 2006.

Kronk, Gary W. “Observing the Orioniids.” Meteor Showers Online.
Available @ http://www.meteorshowersonline.com/orionids.html

Kunitzsch, Paul. Arabische Sternnamen in Europa. Wiesbaden, Germany: Otto Harrassowitch, 1959.

Kunitzsch, Paul; and Tim Smart. Dictionary of Modern Star Names: A Short Guide to 254 Star Names and Their Derivations. Second revised edition. Cambridge MA: Sky Publishing, 2006.

Lunsford, Robert. Meteors and How to Observe Them. Astronomers’ Observing Guides. New York NY: Springer Science+Business Media, 2009.

Marriner, Derdriu. “May 2018 Lunar Perigee Happened Thursday, May 17, During Eta Aquarids.” Earth and Space News. Wednesday, May 23, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/05/may-2018-lunar-perigee-happened.html

Marriner, Derdriu. “Orionid Meteor Shower: Late October Peak of Debris From Comet Halley.” Earth and Space News. Saturday, Oct. 17, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/10/orionid-meteor-shower-late-october-peak.html

Marriner, Derdriu. “Perseid Meteor Shower Continues Through Late August.” Earth and Space News. Wednesday, Aug. 15, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/08/perseid-meteor-shower-continues-through.html

McClure, Bruce. “Orionid Meteor Shower This Weekend!” EarthSky > Tonight. Oct. 19, 2018.
Available @ http: //earthsky.org/?p=2147

“Moon Phases October 2018.” Calendar-12.com > Moon Calendar > 2018.
Available @ https://www.calendar-12.com/moon_calendar/2018/october

WeatherBug Meteorologists. “The Orionid Meteor Shower Peaks This Weekend.” WeatherBug > News. June 28, 2018.
Available @ https://www.weatherbug.com/news/The-Orionid-Meteor-Shower-Peaks-Tonight