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

2018 September Epsilon Perseids Peak Sunday, Sept. 9

Summary: The 2018 September Epsilon Perseids peak Sunday night, Sept. 9, as a monthlong minor annual meteor shower.

Outbursts of the September Epsilon Perseids occurred in 2008 and in 2013. Calculations by Nippon Meteor Society’s Mikiya Sato suggest a possible outburst in 2018: UK Meteor Network @UKMeteorNetwork, via Twitter Sep. 11, 2013

The 2018 September Epsilon Perseids peak Sunday night, Sept. 9, as a monthlong minor annual meteor shower that the International Meteor Organization (IMO) describes as a “primarily northern-hemisphere shower.”

NASA’s Meteoroid Environment Office at Marshall Space Flight Center in Huntsville, north central Alabama, places peak time Sunday, Sept. 9, 2018, at 16:44 Coordinated Universal Time (12:44 p.m. Eastern Daylight Time). Dr. Jürgen Rendtel of northeastern Germany’s Leibniz Institute for Astrophysics Potsdam (AIP) starts the Sept. 9 maximum at 16:00 UTC (12 p.m. EDT). He also notes that meteor specialist Mikiya Sato has calculated a possible outburst, or intense shower, at 19:12 UTC (3:12 p.m. EDT) for the 2018 maximum date.

The International Meteor Organization’s 2018 Meteor Shower Calendar suggests good viewing for observers at mid-northern latitudes as of 22:00 or 23:00 UTC (6 to 7 p.m. EDT). The United Kingdom’s Society for Popular Astronomy’s sky chart orients UK observers toward September Epsilon Perseid tracking in the east-northeastern sky as of “the middle of the night” and “thereafter all night.”

A meteor shower’s peak often benefits adjacent dates with increased rates. Peter Jenniskens, senior research scientist at The Seti Institute and at NASA Ames Research Center in Mountain View, California, identifies the September Epsilon Perseid meteor shower’s maximum as occurring annually from about Sept. 9 to Sept. 12.

The Epsilon Perseid meteor shower’s annual display mostly occurs in September. The International Meteor Organization assigns annual activity dates of Sept. 5 to Sept. 21 to the Epsilon Perseids (ε-Perseids). Robert Lunsford, The American Meteor Society’s Weekly Meteor Activity Outlook columnist, placed activity dates at Sunday, Sept. 3, to Tuesday, Oct. 3, for 2017 and at Monday, Sept. 5, through Wednesday, Sept. 28, for 2016. The American Meteor Society (AMS) gave activity dates of Tuesday, Sept. 5, to Thursday, Sept. 28, for the September Epsilon Perseids in the society’s 2017 Meteor Shower List.

The September Epsilon Perseid (SPE) shower produces bright meteors that move swiftly across the sky. SPE meteors attain entry velocities of around 64 kilometers per second (around 40 miles per second).

Zenithal hourly rate (ZHR) indicates ideal observable rates under optimal radiant and sky conditions. The American Meteor Society and The International Meteor Organization calculate a zenithal hourly rate of five shower members per hour for the September Epsilon Perseids. Apart from the shower’s peak date, a rate of one or less per hour is expected.

The September Epsilon Perseid meteor shower’s peak occurs under ideal lunar conditions. Retired NASA astrophysicist Fred Espenak clocks the moon as turning new at 18:01 UTC (2:01 p.m. EDT) Sunday, Sept. 9. New moon invisibility continues into Monday, Sept. 10.

The dates surrounding the September Epsilon Perseid meteor shower’s peak also are conducive for meteor spotting. The waning crescent phase that precedes the peak date’s new moon dwindles from 8 percent surface visibility of the lunar disk Friday, Sept. 7, down to 3 percent surface visibility Saturday, Sept. 8. The waxing crescent phase that succeeds Sunday and Monday’s new moon offers a slivery surface visibility of only 5 percent for Tuesday, Sept. 11, and 11 percent for Wednesday, Sept. 12.

The September Epsilon Perseid meteor shower’s name reflects an apparent point of origin, known as the shower’s radiant, in Perseus the Hero constellation. A backward tracing of the shower’s meteors in the sky ends near Epsilon Persei (ε Persei; Epsilon Per, ε Per) in the Hero’s constellation.

A meteor shower’s radiant drifts daily about one degree eastward. Radiant diurnal drift parallels Earth’s orbital progression of about one degree per day around the sun.

The September Epsilon Perseid meteor shower’s peak date finds the radiant near Algol (Beta Persei, β Persei; Beta Per, β Per). The three-star system is the second brightest star in Perseus the Hero constellation.

The takeaway for the 2018 September Epsilon Perseid meteor shower’s peak Sunday night, Sept. 9, is that the minor annual shower shoots bright, swift meteors across the Northern Hemisphere’s autumn skies.

September Epsilon Perseid meteor shower’s radiant is in Perseus the Hero constellation; screenshot at 00:01:04 of NASA Jet Propulsion Laboratory’s video Sep. 1, 2016, “What’s Up -- September 2016”: 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:

Outbursts of the September Epsilon Perseids occurred in 2008 and in 2013. Calculations by Nippon Meteor Society’s Mikiya Sato suggest a possible outburst in 2018: UK Meteor Network @UKMeteorNetwork, via Twitter Sep. 11, 2013, @ https://twitter.com/UKMeteorNetwork/status/377925122310410240

September Epsilon Perseid meteor shower’s radiant is in Perseus the Hero constellation; screenshot at 00:01:04 of NASA Jet Propulsion Laboratory’s video Sep. 1, 2016, “What’s Up -- September 2016”: May be used for any purpose without prior permission, via NASA Jet Propulsion Laboratory @ https://www.jpl.nasa.gov/video/details.php?id=1439

For further information:

“2017 Meteor Shower List.” American Meteor Society > Meteor Showers.
Available @ https://www.amsmeteors.org/meteor-showers/2017-meteor-shower-list/

“2018 Alpha Aurigids and September Perseids.” Society for Popular Astronomy > Meteor Showers.
Available @ https://www.popastro.com/main_spa1/meteor/2018-alpha-aurigids-and-september-perseids/

“2018 International Geophysical Calendar (Final).” Space Weather NOW > ISES (International Space Environment Service) > Information.
Available @ http://www.spaceweather.org/ISES/info/geocal/2018.html

Espenak, Fred. “Phases of the Moon: 2001 to 2100.” Astro Pixels > Ephemeris > Moon.
Available @ http://astropixels.com/ephemeris/phasescat/phases2001.html

Gajdoš, Štefan; Juraj Tóth; Leonard Kornoš; Jakub Koukal; and Roman Piffl. “The September epsilon Perseids in 2013.” WGN, Journal of the International Meteor Organization, vol. 42, no. 2 (April 2014): 48-56. Hove, Belgium: International Meteor Organization.
Available @ https://www.imo.net/publications/wgn/

Jenniskens, P. (Peter). “The Established Meteor Showers.” NASA Ames Research Center/SETI (Search for Extraterrestrial Intelligence) CAMS (Cameras for Allsky Meteor Surveillance).
Available via NASA/SETI CAMS @ http://cams.seti.org/maps.html

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

Johannink, Carl. “Activity of the September Perseids.” eMeteorNews, Sept. 15, 2016. Available @ https://www.meteornews.net/2016/09/15/activity-september-perseids/

Lunsford, Robert, coord. “ALPO Meteors Section.” ALPO Association of Lunar & Planetary Observers > Observing Sections.
Available @ http://www.alpo-astronomy.org/meteor/

Lunsford, Robert. “Meteor Activity Outlook for September 2-8, 2017.” American Meteor Society. Aug. 30, 2017.
Available @ https://www.amsmeteors.org/2017/08/meteor-activity-outlook-for-september-2-8-2017/

Lunsford, Robert. “Meteor Activity Outlook for September 9-15, 2017.” American Meteor Society. Sept. 8, 2017.
Available @ https://www.amsmeteors.org/2017/09/meteor-activity-outlook-for-september-9-15-2017/

Lunsford, Robert. “Meteor Activity Outlook for September 16-22, 2017.” American Meteor Society. Sept. 15, 2017.
Available @ https://www.amsmeteors.org/2017/09/meteor-activity-outlook-for-september-16-22-2017/

Lunsford, Robert. “Meteor Activity Outlook for September 23-29, 2017.” American Meteor Society. Sept. 22, 2017.
Available @ https://www.amsmeteors.org/2017/09/meteor-activity-outlook-for-september-23-29-2017/

Lunsford, Robert. “Meteor Activity Outlook for September 30-October 6, 2017.” American Meteor Society. Sept. 29, 2017.
Available @ https://www.amsmeteors.org/2017/09/meteor-activity-outlook-for-september-30-october-6-2017/

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

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

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

Moorhead, Althea; Bill Cooke; and Danielle Moser. “The 2018 Meteor Shower Activity Forecast for Earth Orbit.” NASA Technical Reports Servers. Oct. 13, 2017.
Available via NASA Technical Reports Server (NTRS) @ https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170012378.pdf

Rendtel, Jürgen; Esko Lyytinen; Sirko Molau; and Geert Barentsen. “Peculiar Activity of the September ε-Perseids on 2013 September 9.” WGN, vol. 42, no. 2 (April 2014): 40-47. Hove, Belgium: International Meteor Organization.
Available @ https://www.imo.net/publications/wgn/

Rendtel, Jürgen, ed. “September ε-Perseids (208 SPE).” International Meteor Organization 2016 Meteor Shower Calendar: 13.
Available @ https://www.imo.net/files/meteor-shower/cal2016.pdf

Rendtel, Jürgen, ed. “September ε-Perseids (208 SPE).” International Meteor Organization 2018 Meteor Shower Calendar: 13.
Available @ https://www.imo.net/files/meteor-shower/cal2018.pdf

UK Meteor Network @UKMeteorNetwork. “And here is September Perseid outburst from our station in Ireland, thanks Steve.” Twitter. Sept. 11, 2013.
Available @ https://twitter.com/UKMeteorNetwork/status/377925122310410240

Whitworth, N. John. “September Perseids Meteor Shower.” Universe Guide > Meteor Showers.
Available @ https://www.universeguide.com/meteorshower/septemberperseids