688:, the size of the object depends on the viewing distance. Under normal lighting conditions (light source ~ 1000 lumens at height 600–700 mm, viewing angle ~ 35 degrees) the angular size recognized by naked eye will be round 1 arc minute = 1/60 degrees = 0.0003 radians. At a viewing distance of 16" = ~ 400 mm, which is considered a normal reading distance in the US, the smallest object resolution will be ~ 0.116 mm. For inspection purposes laboratories use a viewing distance of 200–250 mm, which gives the smallest size of the object recognizable to the naked eye of ~0.058–0.072 mm (58–72 micrometers). The
328:
707:
50:
355:. Even a few hundred kilometers away from a metropolitan area where the sky can appear to be very dark, it is still the residual light pollution that sets the limit on the visibility of faint objects. For most people, these are likely to be the best observing conditions within their reach. Under such "typical" dark sky conditions, the naked eye can see stars with an
382:
had most probably been seen but could not be recognized as planets because they appear so faint even at maximum brightness; Uranus's magnitude varies from +5.3 to +5.9, and Vesta's from +5.2 to +8.5 (so that it is only visible near its opposition dates). Uranus, when discovered in 1781, was the first
611:
Many other things can be estimated without an instrument. If an arm is stretched the span of the hand corresponds to an angle of 18 to 20°. The distance of a person, just covered up by the outstretched thumbnail, is about 100 meters. The vertical can be estimated to about 2° and, in the northern
402:
and dust reduces this number somewhat. In the center of a city, where the naked-eye limiting magnitude due to extreme amounts of light pollution can be as low as 2, as few as 50 stars are visible. Colors can be seen but this is limited by the fact that the eye uses
520:
may be visible to the Naked eye only if
Neptune is at its maximum brightness (magnitude +7.8). The Sun and the Moon—the remaining noticeable naked-eye objects of the solar system—are sometimes added to make seven "planets". During daylight only the
860:
Wandell, B. (1995). "Foundations of Vision." Sinauer, Sunderland, MA as cited in
Neurobiology of Attention. (2005). Eds. Laurent Itti, Geraint Rees, and John K., Tsotos. Chapter 102, Elder, J.H. et al. Elsevier,
692:
of a measurement ranges from 0.1 to 0.3 mm and depends on the experience of the observer. The latter figure is the usual positional accuracy of faint details in maps and technical plans.
414:
and galaxies is much more strongly affected by light pollution than is that of planets and stars. Under typical dark conditions only a few such objects are visible. These include the
748:
is a significant problem for amateur astronomers but becomes less late at night when many lights are shut off. Air dust can be seen even far away from a city by its "light dome".
398:
human eye would see the about 5,600 stars brighter than +6 while in perfect dark sky conditions about 45,000 stars brighter than +8 might be visible. In practice, the atmospheric
603:, set a new record as the farthest object that can be seen from Earth with the naked eye. It occurred about 7.5 billion years ago, the light taking that long to reach Earth.
478:
in
Hercules are also visible with the naked eye under such conditions. Under really dark sky conditions, however, M33 is easy to see, even in direct vision. Many other
545:
can be spotted with the naked eye as long as one knows the exact position in which to look. Historically, the zenith of naked-eye astronomy was the work of
871:
549:(1546–1601). He built an extensive observatory to make precise measurements of the heavens without any instruments for magnification. In 1610,
730:
shows how the "blue quality" is degraded depending on the amount of air pollution and dust. The twinkling of a star is an indication of the
907:
482:
are also visible under such conditions. The most distant objects that have been seen by the naked eye are nearby bright galaxies such as
1181:
1101:
1171:
1085:
1019:
359:
up to +6. Under perfect dark sky conditions where all light pollution is absent, stars as faint as +8 might be visible.
114:
845:
86:
790:
133:
1201:
672:
an accuracy of 0.2 second is possible. This represents only 200 meters at the moon's distance of 385,000 km.
1182:
Detection of weak optical signals by the human visual system: Perspectives in
Neuroscience and in Quantum Physics
371:
93:
879:
322:
71:
166:
100:
585:
215:. Sky lore and various tests demonstrate an impressive variety of phenomena visible to the unaided eye.
660:
were calculated by Mayan astronomers, to within 5 to 10 minutes accuracy in the case of Venus and Mars.
231:
from distances of 25 cm (young people) to 50 cm (most people 50 years and older) to infinity.
67:
31:
82:
17:
455:
366:; however, some people have sharper vision than that. There is anecdotal evidence that people had
241:, approximately 0.017° or 0.0003 radians, which corresponds to 0.3 m at a 1 km distance.
508:
with the naked eye: Mercury, Venus, Mars, Jupiter, and Saturn. Under typical dark sky conditions
196:
60:
1069:
1061:
972:
915:
572:
Meteor showers are better observed by naked eye than with binoculars. Such showers include the
399:
264:(brightness) to ±10% or 1% of intensity – in a range between night and day of 1:10,000,000,000.
950:
936:
Zezong, Xi, "The
Discovery of Jupiter's Satellite Made by Gan De 2000 years Before Galileo",
835:
1011:
711:
466:
object and only visible at all if it is higher than 50° in the sky. The globular clusters
8:
739:
723:
715:
261:
192:
367:
1105:
911:
404:
356:
255:
234:
169:
107:
726:
is indicated by the fact that the Milky Way is visible. Comparing the zenith with the
327:
1081:
1015:
1004:
841:
786:
640:
628:
459:
451:
336:
316:
292:
Visual perception allows a person to gain much information about their surroundings:
158:
643:
measured all the basics of their respective time and calendar systems by naked eye:
1073:
681:
636:
501:
487:
423:
395:
281:
1155:
1206:
1038:
762:
745:
647:
the length of a year and a month to ±0.1 hour or to better than 1 minute (0.001%)
596:
562:
550:
491:
479:
352:
340:
37:"Bare eye" redirects here. For the bird genus commonly known as "bare-eyes", see
1077:
1161:
558:
471:
463:
435:
419:
181:
1127:
512:(magnitude +5.8) can be seen as well with averted vision, as can the asteroid
1195:
632:
427:
244:
204:
162:
431:
411:
285:
802:
735:
665:
600:
546:
483:
271:
757:
731:
701:
685:
495:
475:
439:
384:
300:
177:
38:
1102:"Night sky and its wonders - Naked eye astronomy | Hurtling Rock"
990:
247:(FOV): simultaneous visual perception in an area of about 160° × 175°.
1175:
767:
624:
613:
589:
581:
554:
467:
443:
388:
332:
238:
228:
188:
173:
49:
706:
689:
617:
577:
573:
447:
415:
267:
208:
1186:
1187:
The Naked-eye
Planets in the Night Sky (and how to identify them)
727:
651:
542:
534:
517:
513:
379:
212:
1066:
Astrophysics is Easy! An
Introduction for the Amateur Astronomer
872:"Light Pollution and Astronomy: How Dark Are Your Night Skies?"
783:
Sky
Phenomena: A Guide to Naked Eye Observation of the Heavens.
657:
538:
516:
at its brighter oppositions. Under perfect dark sky conditions
509:
375:
351:
The visibility of astronomical objects is strongly affected by
306:
luminosities and colors and their changes by time and direction
296:
the distances and 3-dimensional position of things and persons
277:
Interval estimations (for example at a plan on paper) to 3–5%.
669:
566:
530:
505:
200:
191:, the naked eye may be used to observe celestial events and
522:
344:
251:
616:
and using a protractor can give the observer's geographic
1165:
526:
270:
of 10–20' (3–6 m per 1 km), see the measurements of
331:
A photographic approximation of a naked eye view of the
1068:. Patrick Moore's Practical Astronomy Series. pp.
798:
Auge und Sehen – der lange Weg zu digitalem
Erkennen.
811:
592:
are other popular objects visible to the naked eye.
74:. Unsourced material may be challenged and removed.
1003:
362:The angular resolution of the naked eye is about 1
1001:
537:. Close to sunset and sunrise, bright stars like
529:are obvious naked eye objects, but in many cases
323:Limiting magnitude § In naked-eye visibility
1193:
668:by the moon can be observed. By using a digital
557:towards the sky. He immediately discovered the
905:
533:can be spotted in daylight and in rarer cases
391:) rather than being spotted by the naked eye.
829:
827:
606:
223:Some basic properties of the human eye are:
27:Human vision, unaided by optical instruments
1059:
833:
943:
695:
680:Observing a nearby small object without a
410:The visibility of diffuse objects such as
394:Theoretically, in a typical dark sky, the
995:
824:
675:
134:Learn how and when to remove this message
901:
899:
897:
705:
326:
714:, demonstrating clear atmosphere above
343:dramatically reduces the visibility of
14:
1194:
1033:
1031:
894:
834:Yanoff, Myron; Duker, Jay S. (2009).
734:of the air. This is of importance in
1178:Voyages (archived 22 February 2004).
335:from a small rural town (top) and a
72:adding citations to reliable sources
43:
1028:
218:
195:visible without equipment, such as
24:
710:The Milky Way is visible over the
504:can be recognized as planets from
25:
1218:
1149:
374:before telescopes were invented.
157:, is the practice of engaging in
906:John E. Bortle (February 2001).
806:, 20p., Vol.2000/8, Vienna 2000.
576:(10–12 August) and the December
303:) and the slope of plane objects
48:
1120:
1094:
1053:
650:the 24 hours of a day, and the
310:
59:needs additional citations for
983:
965:
953:. SIMBAD Astronomical Database
930:
878:. 18 July 2006. Archived from
864:
854:
840:. MOSBY Elsevier. p. 54.
620:, up to 1 degree of accuracy.
13:
1:
817:
813:Proceedings, Eisenstadt 1999.
775:
7:
1078:10.1007/978-1-84628-736-7_4
908:"The Bortle Dark-Sky Scale"
751:
586:International Space Station
280:Unconscious recognizing of
258:under a perfectly dark sky.
10:
1223:
699:
612:hemisphere, observing the
320:
314:
36:
32:Naked eye (disambiguation)
29:
837:Ophthalmology 3rd Edition
664:In a similar manner star
607:In geodesy and navigation
383:planet discovered using
1202:Observational astronomy
1132:ESO Picture of the Week
696:Environmental pollution
460:Triangulum Galaxy (M33)
407:to view fainter stars.
1168:and its constellations
1039:"Messier 81 naked-eye"
1002:S. J. O'Meara (1998).
719:
676:Small objects and maps
595:19 March 2008 A major
569:, among other things.
442:, the Ptolemy Cluster
348:
288:system" and reflexes).
1162:Naked-Eye Stargazing:
940:2 (3) (1982): 664–67.
709:
405:rods instead of cones
330:
321:Further information:
250:Ability to see faint
1172:Naked Eye Navigation
1108:on 21 September 2013
1060:Inglis Mike (2007).
1012:Cambridge University
785:FlorisBooks (208p),
712:Very Large Telescope
452:globular cluster M13
207:, and the brightest
68:improve this article
30:For other uses, see
1156:Naked Eye Observing
1006:The Messier Objects
912:Sky & Telescope
876:skyandtelescope.com
716:Paranal Observatory
656:the periods of the
977:astronomy-mall.com
720:
357:apparent magnitude
349:
235:Angular resolution
170:optical instrument
1087:978-1-85233-890-9
1041:. 10 January 1997
1021:978-0-521-55332-2
809:Kahmen H. (Ed.):
793:, Edinburgh 1993.
633:ancient Egyptians
446:near the tail of
337:metropolitan area
317:Naked-eye planets
159:visual perception
144:
143:
136:
118:
16:(Redirected from
1214:
1143:
1142:
1140:
1138:
1124:
1118:
1117:
1115:
1113:
1104:. Archived from
1098:
1092:
1091:
1057:
1051:
1050:
1048:
1046:
1035:
1026:
1025:
1009:
999:
993:
987:
981:
980:
973:"Aintno Catalog"
969:
963:
962:
960:
958:
947:
941:
934:
928:
927:
925:
923:
918:on 23 March 2009
914:. Archived from
903:
892:
891:
889:
887:
882:on 31 March 2014
868:
862:
858:
852:
851:
831:
742:" of astronomy.
682:magnifying glass
559:moons of Jupiter
424:Andromeda Galaxy
372:moons of Jupiter
365:
219:Basic properties
167:light-collecting
139:
132:
128:
125:
119:
117:
76:
52:
44:
21:
1222:
1221:
1217:
1216:
1215:
1213:
1212:
1211:
1192:
1191:
1152:
1147:
1146:
1136:
1134:
1126:
1125:
1121:
1111:
1109:
1100:
1099:
1095:
1088:
1058:
1054:
1044:
1042:
1037:
1036:
1029:
1022:
1000:
996:
988:
984:
971:
970:
966:
956:
954:
949:
948:
944:
938:Chinese Physics
935:
931:
921:
919:
904:
895:
885:
883:
870:
869:
865:
859:
855:
848:
832:
825:
820:
778:
763:Satellite flare
754:
746:Light pollution
704:
698:
678:
637:ancient Indians
609:
599:(GRB) known as
597:gamma-ray burst
584:per night, the
551:Galileo Galilei
492:Sculptor Galaxy
480:Messier objects
462:is a difficult
363:
353:light pollution
341:Light pollution
325:
319:
313:
237:: about 1
221:
140:
129:
123:
120:
77:
75:
65:
53:
42:
35:
28:
23:
22:
15:
12:
11:
5:
1220:
1210:
1209:
1204:
1190:
1189:
1184:
1179:
1169:
1159:
1151:
1150:External links
1148:
1145:
1144:
1119:
1093:
1086:
1052:
1027:
1020:
994:
982:
964:
942:
929:
893:
863:
853:
847:978-0444511416
846:
822:
821:
819:
816:
815:
814:
807:
800:Astro Journal
796:Gerstbach G.:
794:
781:Davidson, N.:
777:
774:
773:
772:
771:
770:
760:
753:
750:
697:
694:
677:
674:
662:
661:
654:
648:
608:
605:
472:Canes Venatici
464:averted vision
436:Omega Centauri
312:
309:
308:
307:
304:
299:the vertical (
297:
290:
289:
278:
275:
265:
259:
248:
242:
232:
220:
217:
205:meteor showers
182:eye protection
149:, also called
142:
141:
56:
54:
47:
26:
9:
6:
4:
3:
2:
1219:
1208:
1205:
1203:
1200:
1199:
1197:
1188:
1185:
1183:
1180:
1177:
1173:
1170:
1167:
1164:Learning the
1163:
1160:
1157:
1154:
1153:
1133:
1129:
1128:"Mars, 2099?"
1123:
1107:
1103:
1097:
1089:
1083:
1079:
1075:
1071:
1067:
1063:
1056:
1040:
1034:
1032:
1023:
1017:
1013:
1010:. Cambridge:
1008:
1007:
998:
992:
986:
978:
974:
968:
952:
946:
939:
933:
917:
913:
909:
902:
900:
898:
881:
877:
873:
867:
857:
849:
843:
839:
838:
830:
828:
823:
812:
808:
805:
804:
799:
795:
792:
791:0-86315-168-X
788:
784:
780:
779:
769:
766:
765:
764:
761:
759:
756:
755:
749:
747:
743:
741:
738:and for the "
737:
733:
729:
725:
717:
713:
708:
703:
693:
691:
687:
683:
673:
671:
667:
659:
655:
653:
649:
646:
645:
644:
642:
638:
634:
630:
626:
621:
619:
615:
604:
602:
598:
593:
591:
587:
583:
579:
575:
570:
568:
564:
560:
556:
552:
548:
544:
540:
536:
532:
528:
524:
519:
515:
511:
507:
503:
499:
497:
493:
489:
488:Bode's Galaxy
485:
481:
477:
473:
469:
465:
461:
457:
453:
449:
445:
441:
437:
433:
429:
428:Carina Nebula
425:
421:
417:
413:
412:star clusters
408:
406:
401:
397:
392:
390:
386:
381:
377:
373:
370:the Galilean
369:
360:
358:
354:
346:
342:
338:
334:
329:
324:
318:
305:
302:
298:
295:
294:
293:
287:
283:
279:
276:
273:
269:
266:
263:
260:
257:
253:
249:
246:
245:Field of view
243:
240:
236:
233:
230:
226:
225:
224:
216:
214:
210:
206:
202:
198:
194:
190:
185:
183:
179:
175:
171:
168:
164:
161:unaided by a
160:
156:
152:
148:
138:
135:
127:
116:
113:
109:
106:
102:
99:
95:
92:
88:
85: –
84:
80:
79:Find sources:
73:
69:
63:
62:
57:This article
55:
51:
46:
45:
40:
33:
19:
1158:in Astronomy
1135:. Retrieved
1131:
1122:
1112:12 September
1110:. Retrieved
1106:the original
1096:
1065:
1055:
1043:. Retrieved
1005:
997:
985:
976:
967:
955:. Retrieved
945:
937:
932:
920:. Retrieved
916:the original
884:. Retrieved
880:the original
875:
866:
856:
836:
810:
801:
797:
782:
744:
721:
679:
666:occultations
663:
622:
610:
594:
571:
502:Five planets
500:
432:Orion Nebula
409:
396:dark adapted
393:
361:
350:
311:In astronomy
291:
222:
211:, including
197:conjunctions
186:
172:, such as a
154:
150:
146:
145:
130:
121:
111:
104:
97:
90:
78:
66:Please help
61:verification
58:
1045:13 November
951:"Vmag<6"
922:18 November
803:Sternenbote
736:meteorology
625:Babylonians
601:GRB 080319B
580:. Some 100
547:Tycho Brahe
484:Centaurus A
272:Tycho Brahe
155:unaided eye
124:August 2012
83:"Naked eye"
1196:Categories
1062:"Galaxies"
991:Messier 81
957:3 December
818:References
776:Literature
758:Macrograph
732:turbulence
724:atmosphere
702:Visibility
700:See also:
686:microscope
582:satellites
553:pointed a
496:Messier 83
440:47 Tucanae
420:h/χ Persei
400:extinction
385:technology
339:(bottom).
315:See also:
301:plumb line
284:(that is "
268:Symmetries
262:Photometry
199:, passing
178:microscope
163:magnifying
94:newspapers
39:Phlegopsis
1176:Polynesia
768:ISS flare
652:equinoxes
614:Pole Star
590:Milky Way
555:telescope
444:Messier 7
389:telescope
333:night sky
256:magnitude
254:up to +8
239:arcminute
229:autofocus
209:asteroids
189:astronomy
174:telescope
147:Naked eye
18:Naked-eye
886:6 August
752:See also
722:A clean
690:accuracy
618:latitude
588:and the
578:Geminids
574:Perseids
561:and the
541:or even
456:Hercules
450:and the
448:Scorpius
416:Pleiades
282:movement
151:bare eye
1137:25 June
1070:157–189
728:horizon
658:planets
641:Chinese
543:Canopus
535:Jupiter
518:Neptune
213:4 Vesta
193:objects
108:scholar
1207:Vision
1084:
1018:
989:SEDS,
844:
789:
740:seeing
639:, and
629:Mayans
563:phases
539:Sirius
510:Uranus
494:, and
458:. The
430:, the
426:, the
422:, the
376:Uranus
227:Quick
201:comets
110:
103:
96:
89:
81:
684:or a
670:clock
567:Venus
531:Venus
514:Vesta
506:Earth
380:Vesta
345:stars
286:alarm
252:stars
180:, or
115:JSTOR
101:books
1139:2012
1114:2013
1082:ISBN
1047:2022
1016:ISBN
959:2009
924:2009
888:2013
861:Inc.
842:ISBN
787:ISBN
623:The
525:and
523:Moon
476:M 92
474:and
378:and
368:seen
87:news
1166:Sky
1074:doi
565:of
527:Sun
470:in
468:M 3
454:in
387:(a
187:In
176:or
153:or
70:by
1198::
1174:,
1130:.
1080:.
1072:.
1064:.
1030:^
1014:.
975:.
910:.
896:^
874:.
826:^
718:.
635:,
631:,
627:,
498:.
490:,
486:,
438:,
434:,
418:,
203:,
184:.
165:,
1141:.
1116:.
1090:.
1076::
1049:.
1024:.
979:.
961:.
926:.
890:.
850:.
364:′
347:.
274:.
137:)
131:(
126:)
122:(
112:·
105:·
98:·
91:·
64:.
41:.
34:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
