Orionids

(or-ÿ -ŏ-nidz, oh-rÿ ) An active meteor shower, radiant: RA 97°, dec +15°, that maximizes on Oct. 22 with a zenithal hourly rate of about 25. The activity has been observed to change by as much as a factor of four between one year and the next. The shower has been the center of controversy firstly because it was thought that the radiant was stationary during the three weeks of activity. This view has now been abandoned: all showers have radiants that move with respect to the stars as the Earth moves along its orbit. Secondly the shower is associated both with Halley's comet and the Eta Aquarids because of similarities in orbital elements.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Orionids

[ə′rī·ə‚nidz]

(astronomy)

A meteor shower seen in October in the northern hemisphere; its radiant lies in the constellation Orion.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Orionids

a meteor shower with its radiant in the constellation Orion. Linked with Halley’s comet, the Orionids are active every year in the second half of October. The Eta Aquarid meteor shower is also linked with Halley’s comet. The Eta Aqua-rids are active from the end of April to the beginning of May.

Mentioned in

Meteor Stream

References in periodicals archive

Unfortunately the Orionids, Leonids, and Geminids in 1997 will be largely hidden by moonlight.

Meteor showers

For visual observers, the familiar Orionids (ORI), which are particles shed by Comet Halley, mask the faster Epsilon Geminids (EGE), which had been suspected from sparse photographic data but are now confirmed.

New meteor showers discovered: as Earth circles the Sun, it crosses a rich and changing tangle of meteoroid streams. Automated cameras are mapping them better than ever

Delta Aquarids [e] Jul 29 Jul 21-Aug 29 22 36 Alpha Capricornids [f] Jul 30 Jul 15-Aug 25 20 28 Orionids [d] Oct 21 Oct 02-Nov 07 06 20 Southern Taurids [g] Nov 05 Oct 01-Nov 25 03 20 Northern Taurids Nov 12 Oct 01-Nov 25 04 00 Leonids [h] Nov 17 Nov 12-Nov 21 10 08 Alpha Monocerotids Nov 21 Nov 15-Nov 25 07 48 Dec.

Meteors

During the coming autumn observing season, moonlight will unfortunately interfere with the maxima of the Orionids and Leonids, with Full Moon occurring on October 23 and November 21, respectively.

This autumn's meteor activity

The Orionids, fragments of the periodic comet 1P/ Halley, are unusually swift.

Draconid meteor outburst? On the evening of October 8th, some places may get quite a show

Moonlight was no problem during the Orionids, with a broad maximum being recorded on October 21-23 when highest rates were about 40 m/h, slightly greater than usual.

Meteor section

The Eta Aquarids and the Orionids of October are the same meteoroid stream, shed by Comet Halley.

Big black asteroid in Libra: the largest asteroid you've probably never heard of is now unusually close

Sadly two of the autumn's main meteor showers, the Orionids (Oct 22) and the Leonids (Nov 18), are not favourable this year, due to the maximum nights being near to the full Moon.

Sky notes: 2010 October and November

[ILLUSTRATION OMITTED] Meteor Shower Day Shower Duration 21 Orionids Oct 02--Nov 07 -- Southern Taurids Oct 01--Nov 25 -- Northern Taurids Oct 01--Nov 25 Date of maximum activity.

October 2009