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352:. Along with beheading Medusa, Perseus performed other heroic deeds such as saving princess Andromeda who was chained to a rock as a sacrifice to a sea monster, Cetus. The gods commemorated Perseus by placing him among the stars, with the head of Medusa in one hand and the jeweled sword in the other. The Double Cluster represents the jeweled handle of his sword.
332:, which peaks annually around August 12 or 13. Although easy to locate in the northern sky, observing the Double Cluster in its two parts requires optical aid. They are described as being an "awe-inspiring" and "breathtaking" sight, and are often cited as a target in astronomy observer's guides.
375:
Currie, Thayne; Hernandez, Jesus; Irwin, Jonathan; Kenyon, Scott J.; Tokarz, Susan; Balog, Zoltan; Bragg, Ann; Berlind, Perry; Calkins, Mike (2010). "The
Stellar Population of h and χ Persei: Cluster properties, membership, and the intrinsic colors and temperatures of stars".
207:
NGC 869 has a mass of 4,700 solar masses and NGC 884 weighs in at 3,700 solar masses; both clusters are surrounded with a very extensive halo of stars, with a total mass for the complex of at least 20,000 solar masses. They form the core of the
258:
cataloged the object (a patch of light in
Perseus) as early as 130 BCE. To Bedouin Arabs the cluster marked the tail of the smaller of two fish they visualized in this area, and it was shown on illustrations in
324:. This northern location renders this object invisible from locations south of about 30º south latitude, such as New Zealand, most of Australia and South Africa. The Double Cluster is approximately the
226:, with NGC 869 approaching Earth at a speed of 39 km/s (24 mi/s) and NGC 884 approaching at a similar speed of 38 km/s (24 mi/s). Their hottest main sequence stars are of
294:(1603). It is sometimes claimed that Bayer did not resolve the pair into two patches of nebulosity, and that χ refers to the Double Cluster and h to a nearby star. Bayer's
269:. However, the true nature of the Double Cluster was not discovered until the invention of the telescope, many centuries later. In the early 19th century
1505:
273:
was the first to recognize the object as two separate clusters. The Double
Cluster is not included in Messier's catalog, but is included in the
825:
432:
Keller, Stefan C.; Grebel, Eva K.; Miller, Grant J.; Yoss, Kenneth M. (2001). "UBVI and Hα photometry of the h and χ Persei cluster".
28:
477:
Kharchenko, N.V.; Piskunov, A.E.; Röser, S.; Schilbach, E.; Scholz, R.-D. (2005). "Astrophysical parameters of
Galactic open clusters".
1411:
567:
1426:
724:
188:. Both visible with the naked eye, NGC 869 and NGC 884 lie at a distance of about 7,500 light years in the
298:
chart for
Perseus does not show them as nebulous objects, but his chart for Cassiopeia does, and they are described as
215:
Based on their individual stars, the clusters are relatively young, both 14 million years old. In comparison, the
184:(often designated h Persei and χ (chi) Persei, respectively), which are close together in the constellation
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818:
790:
782:
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320:(continuously above the horizon) from most northern temperate latitudes. It is in proximity to the constellation
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778:
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1500:
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304:
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222:
There are more than 300 blue-white super-giant stars in each of the clusters. The clusters are also
559:
321:
1495:
1449:
798:
1315:
632:
O'Meara, Stephen James; Green, Daniel W.E. (February 2003). "The mystery of the Double
Cluster".
609:
325:
185:
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260:
157:
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8:
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Star Tales – Andromeda Galaxy and the Double
Cluster in al-Sufi's Book of the Fixed Stars
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385:
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127:
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have an estimated age ranging from 75 million years to 150 million years.
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238:, AD Persei, FZ Persei, V403 Persei, and V439 Persei.
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Perseus was a famous hero of Greek mythology, a son of the Greek god
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The Double
Cluster in Perseus (lower left of center, wide angle view)
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234:stars, all variable and all around 8th magnitude:
1482:
631:
672:Chaple, Glenn (January 2011). "A double take".
636:. Vol. 105, no. 2. pp. 116–119.
576:
819:
339:The Double Cluster in Perseus, visible light.
553:
1506:Astronomical objects known since antiquity
1412:Catalogue of Nebulae and Clusters of Stars
826:
812:
16:Open clusters in the constellation Perseus
665:
490:
445:
389:
308:, which was assembled with Bayer's help.
230:B0. NGC 884 includes five prominent
682:
651:. McDonald & Woodward. p. 240.
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378:The Astrophysical Journal Supplement
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284:h Persei and χ Persei by
13:
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709:
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1454:
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212:association of young hot stars.
27:
743:. Dark Atmospheres Photography.
611:Star Tales – The Double Cluster
554:O'Meara, Stephen James (2002).
640:
625:
470:
41:(below) with north to the left
1:
1427:Revised New General Catalogue
355:
277:of popular deep-sky objects.
202:
753:Astronomy Picture of the Day
343:
305:Coelum Stellatum Christianum
108:Apparent dimensions (V)
7:
678:. Vol. 39, no. 1.
408:10.1088/0067-0049/186/2/191
311:
10:
1522:
560:Cambridge University Press
509:10.1051/0004-6361:20042523
479:Astronomy and Astrophysics
241:
47:Observation data (J2000.0
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26:
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755:. NASA. 4 December 2009.
741:"Perseus Double Cluster"
434:The Astronomical Journal
119:Physical characteristics
647:Wagman, Morton (2003).
501:2005A&A...438.1163K
1432:Herschel 400 Catalogue
340:
316:The Double Cluster is
251:
1501:Asterisms (astronomy)
1417:New General Catalogue
338:
330:Perseid meteor shower
261:Abd al-Rahman al-Sufi
249:
158:List of open clusters
749:"The Double Cluster"
692:Star Tales – Perseus
556:The Caldwell Objects
57:Right ascension
33:The Double Cluster,
799:Articles and images
456:2001AJ....122..248K
400:2010ApJS..186..191C
266:Book of Fixed Stars
835:Caldwell catalogue
761:Double Cluster on
341:
280:The clusters were
275:Caldwell catalogue
252:
173:) consists of the
124:Other designations
98:Apparent magnitude
1478:
1477:
1407:Messier Catalogue
634:Sky and Telescope
586:. Caldwell Club.
569:978-0-521-82796-6
254:Greek astronomer
163:
162:
1513:
1496:Caldwell objects
1468:
1458:
1457:
1448:
1447:
828:
821:
814:
805:
804:
756:
744:
736:
731:. Archived from
725:"Double Cluster"
720:
717:"Double Cluster"
704:
703:
701:
700:
695:. Online edition
686:
680:
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669:
663:
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614:. Online edition
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536:. Online edition
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492:astro-ph/0501674
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447:astro-ph/0104179
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1422:Index Catalogue
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300:Nebulosa Duplex
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88:(2,290 and 2340
84:7,460 and 7,640
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735:on 2007-08-20.
729:AstroPhoto.net
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710:External links
708:
706:
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689:Ridpath, Ian.
681:
664:
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639:
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608:Ridpath, Ian.
600:
584:"Introduction"
575:
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530:Ridpath, Ian.
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464:10.1086/321139
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302:in Schiller's
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232:red supergiant
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167:Double Cluster
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1491:Open clusters
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228:spectral type
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175:open clusters
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141:Constellation
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733:the original
728:
697:. Retrieved
691:
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673:
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616:. Retrieved
610:
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591:. Retrieved
587:
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538:. Retrieved
532:
525:
482:
478:
472:
437:
433:
381:
377:
347:
315:
303:
299:
295:
289:
286:Johann Bayer
279:
264:
253:
221:
214:
206:
170:
166:
164:
154:Open cluster
135:Associations
37:(above) and
593:8 September
485:(3): 1163.
318:circumpolar
296:Uranometria
291:Uranometria
224:blueshifted
210:Perseus OB1
190:Perseus Arm
171:Caldwell 14
103:3.7 and 3.8
67:Declination
1485:Categories
791:Astrophoto
783:Hydrogen α
699:2021-09-19
658:0939923785
649:Lost Stars
618:2024-02-24
540:2021-09-19
440:(1): 248.
384:(2): 191.
356:References
322:Cassiopeia
282:designated
256:Hipparchus
203:Membership
152:See also:
675:Astronomy
391:0911.5514
344:Mythology
236:RS Persei
194:Milky Way
100: (V)
61:2 20
1450:Category
1400:See also
416:16454332
312:Location
217:Pleiades
130: 14
128:Caldwell
80:Distance
1460:Commons
795:Sky Map
763:WikiSky
719:. SEDS.
517:9079873
497:Bibcode
452:Bibcode
396:Bibcode
328:of the
326:radiant
288:in his
242:History
192:of the
186:Perseus
182:NGC 884
178:NGC 869
146:Perseus
39:NGC 884
35:NGC 869
1470:Portal
655:
566:
515:
414:
197:galaxy
71:57° 08
787:X-Ray
775:GALEX
513:S2CID
487:arXiv
442:arXiv
412:S2CID
386:arXiv
49:epoch
1391:C109
1386:C108
1381:C107
1376:C106
1371:C105
1366:C104
1361:C103
1356:C102
1351:C101
1346:C100
843:List
779:IRAS
771:SDSS
767:DSS2
653:ISBN
595:2006
564:ISBN
350:Zeus
180:and
165:The
1341:C99
1336:C98
1331:C97
1326:C96
1321:C95
1316:C94
1311:C93
1306:C92
1301:C91
1296:C90
1291:C89
1286:C88
1281:C87
1276:C86
1271:C85
1266:C84
1261:C83
1256:C82
1251:C81
1246:C80
1241:C79
1236:C78
1231:C77
1226:C76
1221:C75
1216:C74
1211:C73
1206:C72
1201:C71
1196:C70
1191:C69
1186:C68
1181:C67
1176:C66
1171:C65
1166:C64
1161:C63
1156:C62
1151:C61
1146:C60
1141:C59
1136:C58
1131:C57
1126:C56
1121:C55
1116:C54
1111:C53
1106:C52
1101:C51
1096:C50
1091:C49
1086:C48
1081:C47
1076:C46
1071:C45
1066:C44
1061:C43
1056:C42
1051:C41
1046:C40
1041:C39
1036:C38
1031:C37
1026:C36
1021:C35
1016:C34
1011:C33
1006:C32
1001:C31
996:C30
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