97:
645:
88:, against the stellar background each day. This is called the radiant's diurnal drift, and is to a large degree due to the Earth's own orbital motion around the Sun, which also proceeds at nearly one degree a day. As the radiant is determined by the superposition of the motions of Earth and meteoroid, the changing orbital direction of the Earth towards the east causes the radiant to move to the east as well.
20:
66:
of the meteor paths, which are parallel lines in three-dimensional space, as seen from the perspective of the observer, who views a two-dimensional projection against the sky. The geometric effect is identical to
206:
147:, then few if any meteors will be observed. This is because the atmosphere shields the Earth from most of the debris, and only those meteors which happen to be travelling exactly (or very near)
120:, a meteor shower results. Because all of the debris is moving in roughly the same direction, the meteors which strike the atmosphere all "point" back to the direction of the comet's path.
81:
Shower meteors may appear a short time before the radiant has risen in the observer's eastern sky. The radiant in such cases is above the horizon at the meteor's altitude.
62:
Meteor paths appear at random locations in the sky, but the apparent paths of two or more meteors from the same shower will diverge from the radiant. The radiant is the
210:
242:
167:
810:
820:
235:
84:
During the active period of most showers, the radiant moves nearly one degree eastwards, parallel to the
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873:
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228:
56:
852:
805:
185:
96:
835:
143:
The radiant is an important factor in observation. If the radiant point is at or below the
8:
55:, for example, are meteors which appear to come from a point within the constellation of
74:
A meteor that does not point back to the known radiant for a given shower is known as a
765:
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24:
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from which (from the point of view of a terrestrial observer) the paths of
750:
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112:. This dust continues to move along the comet's wake, and when the
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Celestial point in the sky from which meteors appear to originate
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186:"IAUC 3881: 1983 TB AND THE GEMINID METEORS; 1983 SA; KR Aur"
113:
109:
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Geminid meteors, clearly showing the position of the radiant
19:
171:
105:
104:Meteor showers are mostly caused by the trails of
865:
183:
236:
71:, where parallel sunbeams appear to diverge.
188:. International Astronomical Union Circular
78:and is not considered part of that shower.
243:
229:
207:"Exploding Clays Drive Geminids Sky Show?"
151:to the Earth's surface will be viewable.
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18:
177:
866:
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168:Earth Observatory Glossary: Radiant
13:
643:
250:
127:are a shower caused by the object
14:
885:
811:International Meteor Organization
108:and debris left in the wake of a
27:, with the radiant marked by 'ᴏ'
566:Sextantids (Daytime Sextantids)
184:Brian G. Marsden (1983-10-25).
383:Cassiopeids (beta Cassiopeids)
199:
161:
138:
1:
821:North American Meteor Network
563:Serpentids (kappa Serpentids)
154:
209:. 2010-10-12. Archived from
7:
131:, which is thought to be a
10:
890:
520:September epsilon Perseids
45:celestial point in the sky
843:
794:
638:
437:Eridanids (eta Eridanids)
429:Doradids (gamma Doradids)
258:
51:appear to originate. The
296:Southern Delta Aquariids
91:
801:American Meteor Society
496:Normids (gamma Normids)
853:List of meteor showers
806:Earth-grazing fireball
648:
468:(Dec. Leonis Minorids)
371:Daytime Capri.-Sagitt.
101:
28:
647:
558:South omega Scorpiids
555:North omega Scorpiids
318:Daytime eps. Arietids
286:North delta Aquariids
123:As an exception, the
99:
22:
836:Zenithal Hourly Rate
321:Daytime May Arietids
292:South iota Aquariids
289:North iota Aquariids
308:South June Aquilids
116:moves through such
716:July 31 – August 1
649:
490:alpha Monocerotids
443:(epsilon Geminids)
400:omicron Centaurids
367:alpha Capricornids
339:Nov. iota Aurigids
133:Palladian asteroid
102:
29:
861:
860:
816:Meteor procession
531:Piscis Austrinids
528:(July Phoenicids)
270:Antihelion Source
881:
849:
826:Population index
646:
617:lambda Virginids
586:Southern Taurids
581:Northern Taurids
418:Comae Berenicids
395:theta Centaurids
390:alpha Centaurids
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238:
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197:
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69:crepuscular rays
37:apparent radiant
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857:
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629:March Virginids
611:theta Virginids
605:gamma Virginids
602:alpha Virginids
552:alpha Scorpiids
466:Leonis Minorids
283:kappa Aquariids
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64:vanishing point
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874:Meteor showers
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795:Related topics
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776:December 13–14
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766:November 21–22
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358:delta Cancrids
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352:Canis-Minorids
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335:delta Aurigids
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331:alpha Aurigids
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252:Meteor showers
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213:on 2010-10-17.
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626:psi Virginids
625:
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608:eta Virginids
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541:Puppid-Velids
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516:zeta Perseids
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455:sigma Hydrids
452:
449:
448:tau Herculids
445:
442:
439:
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425:
424:kappa Cygnids
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398:
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363:Capricornids
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338:
336:
333:
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329:
328:
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320:
317:
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312:
307:
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300:tau Aquariids
299:
297:
294:
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285:
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279:eta Aquariids
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129:3200 Phaethon
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50:
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42:
41:meteor shower
38:
34:
26:
25:meteor shower
21:
830:
771:December 5–6
639:By peak date
623:pi Virginids
620:mu Virginids
576:beta Taurids
485:Monocerotids
409:omega Cetids
378:eta Carinids
346:June Bootids
211:the original
201:
190:. Retrieved
179:
163:
142:
122:
103:
83:
80:
75:
73:
61:
36:
32:
30:
786:December 22
781:December 15
761:November 18
756:November 12
726:September 1
676:April 22–23
663:February 10
545:Quadrantids
479:June Lyrids
446:Herculids (
386:Centaurids
266:Andromedids
139:Observation
23:Image of a
751:November 9
746:October 22
741:October 21
736:October 10
706:July 28–29
658:February 8
549:Scorpiids
536:pi Puppids
526:Phoenicids
476:eta Lyrids
376:Carinids (
356:Cancrids (
192:2011-07-05
155:References
149:tangential
731:October 8
721:August 13
653:January 4
598:Virginids
534:Puppids (
453:Hydrids (
433:Draconids
422:Cygnids (
412:pi Cetids
344:Bootids (
305:Aquilids
274:Aquariids
868:Category
848:See also
681:April 26
671:April 17
667:March 14
574:Daytime
514:Daytime
510:Perseids
505:Pegasids
500:Orionids
441:Geminids
327:Aurigids
314:Arietids
125:Geminids
86:ecliptic
76:sporadic
53:Perseids
831:Radiant
711:July 30
701:July 13
696:June 27
570:Taurids
461:Leonids
406:Cetids
259:By name
145:horizon
57:Perseus
49:meteors
43:is the
33:radiant
691:June 7
593:Ursids
472:Lyrids
118:debris
686:May 6
114:Earth
110:comet
92:Cause
39:of a
174:.gov
172:NASA
106:dust
31:The
170:on
35:or
870::
135:.
59:.
538:)
457:)
450:)
426:)
380:)
360:)
348:)
244:e
237:t
230:v
195:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
