Aquarids


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Related to Aquarids: d Aquarids

meteor shower

meteor shower, increase in the number of meteors observed in a particular part of the sky. The trails of the meteors of a meteor shower all appear to be traceable back to a single point in the sky, known as the radiant point, or radiant. A shower is named for the constellation in which its radiant is located, e.g., the Lyrids appear to come from a point in Lyra, the Perseids from Perseus, and the Orionids from Orion.

Meteor showers usually occur annually and with varying intensity. While the average counting rate of meteors for the entire sky is between 5 and 10 per hr, an observer may see twice this number in one part of the sky during a shower, depending on atmospheric conditions and the degree of darkness, and in the case of the Perseids, possibly more than 100 in an hour. The Leonids produce spectacular displays roughly every 33 years, as they did during the meteor storm of 1966 (with a peak of a thousand a minute) and the intense shower of 2001 (with a peak of several thousand an hour). The Taurids, though not intense in number of meteors, is noted for the spectacular fireballs it displays.

Most meteor showers are closely associated with comets. When a comet approaches the sun, a swarm of particles is shed along its orbit. If this orbit intersects that of the earth, a meteor shower will be observed. The shower will be particularly intense in those years when the original comet would have been observed. The Geminids are an exception; they are associated with the asteroid 3200 Phaethon. The Andromedids are associated with Biela's comet, the Eta Aquarids and Orionids with Halley's comet, the Leonids with Comet Tempel-Tuttle, the Lyrids with Comet Thatcher, the Perseids with Comet Swift-Tuttle, and the Taurids with Comet Encke. Some of the better-known meteor showers and their approximate peak dates are: Lyrids, Apr. 21; Perseids, Aug. 12; Orionids, Oct. 20; Taurids, Nov. 4; Leonids, Nov. 16; Geminids, Dec. 13.

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Aquarids

(ak -wă-ridz) Either of two active meteor showers: the Eta Aquarids, radiant: RA 336°, dec 0°, maximize on May 6, having a peak duration of 10 days and a zenithal hourly rate (ZHR) of 45; the Delta Aquarids, double radiant: RA 340°, dec –17° and 0°, maximize on July 28 and Aug. 7, have a peak duration of about 20 days, and a ZHR of about 19 and 10. The Eta Aquarids have an orbit that is closely aligned to that of Halley's comet. They are observed near the descending node of the comet's orbit.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Aquarids

 

meteor showers whose radiants are located in the Big Dipper. The most important aquarids are the Eta Aquarids (visible every year at the end of April and beginning of May), which are connected with Halley’s Comet, and the Delta Aquarids (visible every year at the end of July and beginning of August).

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
In an online article, the US National Aeronautics and Space Administration (Nasa) said the Delta Aquarids were best viewed in the southern hemisphere and the southern latitudes of the northern hemisphere.
Experts say this is a very good year to look out for the Eta Aquarid meteors because the moon will be at a thin, waning crescent phase, and just 20-percent illuminated and providing little interference for viewing these swift streaks of light.
Almanac d h Event 01 01:00 Moon near Regulus (5.7[degrees]N) 04 19:26 Moon near Spica (1.5[degrees]N) 04 20:08 Eta Aquarid Shower (ZHR = 60) 06 05:33 Moon at perigee (357 000 km) 06 05:35 Full Moon (diameter 33.7') 07 11:43 Moon at ascending node 07 19:00 Moon near Antares (5.0[degrees]S) 08 08:18 Moon max.
Eta Aquarids are known for their speed and will be traveling at about 148,000 mph while entering Earth's atmosphere.
According to space.com, the Eta Aquarids do not produce as many meteors per hour as the more famous Perseid meteor shower in August, but they are just as bright, if not brighter.
In an online article, the US National Aeronautics and Space Administration said the Delta Aquarids are best viewed in the southern hemisphere and the southern latitudes of the northern hemisphere.
Several minor, long-lasting meteor showers with radiants in the southern sky are active during July, including the Alpha Capricornids, Piscis Austrinids, and Northern and Southern Delta Aquarids. All are weak, but together they increase the chance that a meteor you see late on a July night will be coming out of the south.
(2) He published numerous accounts of his meteor work in the English Mechanic, including a thorough analysis of his observations of the 1907 Aquarids. (97) He reported on 3 fireballs 'brighter than Venus' that were seen in the skies over Belgium in 1908 May.
of Showers Observed and duration Total Time showers observed hrs Tim Cooper (2) Pi Puppids (1.0), eta Aquarids (8.5) 9.5 Dudley Field (3) Alpha Crucids (2.1), Pi Puppids 7.6 (3.1), alpha Capricornids (2.4) Koos van Zyl (1) Alpha Crucids (6.3) 6.3 Karen Koch (2) Alpha Crucids (2.3), Alpha 5.3 Centaurids (3.0) Magda Streicher (1) Eta Aquarids (2.2) 2.2 Kos Coronaios (1) Alpha Centaurids (0.5) 0.5 Total 31.4 Table 2.
But the small green fireballs were actually part of the Delta Aquarids meteor shower, usually visible from mid-July to midAugust.