Ukusitheka kweNyanga akusoloko kungumboniso ofanayo. Ngamanye amaxesha iNyanga iba mfiliba kancinane kuphela; ngamanye amaxesha igophe elimnyama libonakala ngathi liluma inxalenye yayo; yaye ngamanye amaxesha yonke idiski yeNyanga iba bomvu bumdaka. Umahluko uxhomekeke kwindlela iNyanga ewela ngayo kumthunzi woMhlaba. La magama mathathu—ukusitheka kwi-penumbra, okuyinxenye nokupheleleyo—achaza ukuba ingakanani inxalenye yeNyanga engena kweyona ndawo imnyama yaloo mthunzi, ebizwa ngokuba yi-umbra. Ukuqonda ukuma kwezi zinto kwenza kube lula ukuqaphela okwenzekayo, ingakumbi xa utshintsho lungabonakali lula. Ukuze ufumane imihla yokusitheka, amaxesha okuqala nokuphela kwezigaba, ubude bexesha nokubonakala kwaso kwiindawo ezahlukeneyo, sebenzisa ikhathalogu yokusitheka kweNyanga ehlaziywa ngexesha langoku.
UMhlaba wenza iindidi ezimbini zemithunzi
ILanga ngumthombo wokukhanya obanzi, aliyonto nje eyichaphaza. Ngenxa yoko, uMhlaba wenza indawo esembindini apho ukukhanya kweLanga kungafikeleliyo, kwakunye nendawo engaphandle apho inxalenye kuphela yeLanga ivalekileyo. Umthunzi osembindini yi-umbra; umthunzi othambileyo ongaphandle yi-penumbra. Umda ophakathi kwazo umiselwa yindlela ezimi ngayo ezi zinto: kwi-penumbra, umntu obukeleyo oseNyangeni ebeya kukwazi ukubona inxalenye yeLanga, kanti kwi-umbra uMhlaba ubeya kulivala ngokupheleleyo iLanga.
Ukusitheka kweNyanga kunokwenzeka kuphela xa kukho inyanga epheleleyo, xa uMhlaba uphakathi kweLanga neNyanga. Kodwa uninzi lweenyanga ezipheleleyo ludlula ngaphezu okanye ngaphantsi komthunzi woMhlaba kuba umjikelo weNyanga uthambekele ngee-degrees eziyi-5.14 xa uthelekiswa ne-ecliptic, inqwelo-moya yomjikelo woMhlaba ojikeleza iLanga. Ukusitheka kwenzeka xa inyanga epheleleyo isondele kwindawo ezinqumla kuyo ezi nqwelo-moya zemijikelo. Isikhokelo sezigaba zeNyanga sichaza ukuba kutheni isigaba seNyanga sixhomekeke kwindawo yayo xa ithelekiswa neLanga noMhlaba; uhlobo lokusitheka lona luxhomekeke kwindlela ehamba ngayo iNyanga kumthunzi woMhlaba.
Ukusitheka kwi-penumbra: ukufiphala okuthambileyo nokusasazekileyo
Xa iNyanga isitheka kwi-penumbra, idlula kwi-penumbra yoMhlaba kodwa ingafikeleli kwi-umbra. Akukho mda umnyama ucace gca unqumla idiski yeNyanga. Kunoko, inxalenye okanye yonke iNyanga ifumana ukukhanya kweLanga okuthe ngqo okuncinane, ize ibonakale ngathi inomthunzi omncinane, ngokuqhelekileyo kwicala elikufutshane ne-umbra. Kulula ukungaluqapheli olu tshintsho, ingakumbi ekuqaleni okanye ekupheleni kweso siganeko, xa inxalenye encinane kuphela yeNyanga ikwi-penumbra.
Yiyo loo nto ukusitheka kweNyanga kwi-penumbra kunokuba kukudibana kwezinto zasemajukujukwini okwenzeka ngokwenene nokunokulinganiswa, kodwa kungabonakali kumangalisa xa ukujonga ngeliso lenyama. Kunokubonakala ngakumbi efotweni kunokuba kubonakale xa ukrobe nje ngokukhawuleza, kodwa ukuseta okuzenzekelayo kwekhamera kunokulungelelanisa ukukhanya kuze kwenze kube nzima ukuthelekisa imifanekiso. Ukuba uyafota, gcina indlela omi ngayo ifoto nezicwangciso zokukhanya zingatshintshi, uze uyithelekise nefoto oyithathe ngaphambi okanye emva kokusitheka. Ukusitheka kwi-penumbra akuthethi ukuba iNyanga idlula kwilifu okanye itshintsha ukukhanya kwayo; kukuncipha kancinci kokukhanya kweLanga okubangelwa kukuba uMhlaba ulivala ngokuyinxenye iLanga xa ujonge eNyangeni.
Ngokomzekelo, ukusitheka kweNyanga kwi-penumbra nge-20 Februwari 2027 kuboniswe njengokuthatha imizuzu eyi-241. Eli xesha lide alithethi ukuba iNyanga iya kubonakala imnyama ngokucacileyo kangangeeyure ezine: umthunzi utshintsha ngokuthe ngcembe, yaye eyona ndawo inzulu ye-penumbra isenokubonakala ngakumbi kunomphetho wayo ongaphandle ongacacanga. Ikhalenda kaFebruwari 2027 ehlaziywa ngexesha langoku inika amaxesha achanekileyo ezigaba zeNyanga kuloo nyanga, kanti ikhathalogu yokusitheka inika iinkcukacha zesiganeko.
Ukusitheka okuyinxenye: igophe elimnyama lihamba linqamle iNyanga
Ukusitheka kweNyanga okuyinxenye kwenzeka xa inxalenye ethile yeNyanga ingena kwi-umbra, ngoxa enye inxalenye ihleli ngaphandle kwayo. Olona phawu lubonakala lula ligophe elimnyama ngokucacileyo elikhula linqamle ubuso beNyanga. Umda we-umbra ugobile kuba uMhlaba ungqukuva; ukusitheka kweNyanga kwanceda ababukeli baqonda loo milo kwakude kudala ngaphambi kokuba iziphekepheke zikwazi ukufota uMhlaba usemajukujukwini.
Umthunzi awuyonto eqinileyo ebekwe phezu kweNyanga, yaye umda wawo awucaci gca. Ukukhanya kweLanga okudlula kwiatmosfera yoMhlaba kuyawuthambisa loo mda. Sekunjalo, umahluko phakathi kwenxalenye ekhanyayo engaphandle kwe-umbra nenxalenye emfiliba engaphakathi kuyo udla ngokubonakala ngakumbi kunesithunzi sokusitheka kwi-penumbra. INyanga ayipheli xa isitheka ngokuyinxenye, yaye inxalenye eseleyo ngaphandle kwe-umbra iyaqhubeka ikhanyiswa kukukhanya kweLanga okuthe ngqo.
Ingakanani inxalenye yeNyanga egqunywayo iyahluka ngokwendlela esihamba ngayo isiganeko sokusitheka. Ukungena nje kancinci kwi-umbra kushiya inotshi encinane emnyama; ukungena nzulu kunokugquma uninzi lwediski kodwa kungayigqumi yonke. Olu didi luxhomekeke kwindawo ekuyo iNyanga emthunzini, kungekhona ekubeni umntu obukeleyo angasibona na isiganeko. Umda wendawo obonakalayo, ukukhanya kwemini, imozulu nendawo ekuyo iNyanga esibhakabhakeni zonke zichaphazela ukubonakala kwayo. Ideshibhodi yesixeko efana ne-iphepha leNyanga laseLondon ibonisa ukuphuma nokutshona kweNyanga kwalapho, ukuphakama kwayo, i-azimuth nemozulu, nto leyo enokunceda ekucwangciseni ukubukela isibhakabhaka ngokubanzi.
Ukusitheka okupheleleyo: iNyanga ingena yonke kwi-umbra
Xa iNyanga isitheka ngokupheleleyo, yonke idiski yayo idlula ngaphakathi kwe-umbra yoMhlaba. INyanga isabonakala kuba iatmosfera yoMhlaba igoba inxalenye yokukhanya kweLanga kuze kungene emthunzini. Njengoko oko kukhanya kudlula kwiatmosfera, amaza amafutshane okukhanya aluhlaza asasazeka ngamandla ngakumbi kunalawo abomvu. Ngenxa yoko, ukukhanya okuseleyo okufikelela eNyangeni kudla ngokuba bomvu okanye kubeorenji, yaye umphezulu weNyanga ukubuyisela oko kukhanya kubabukeli abaseMhlabeni.
Ibinzana elidumileyo elithi “inyanga yegazi” libhekisela kule mbonakalo inokuba bomvu, alibhekiseli kuhlobo olwahlukileyo lokusitheka okanye kumbala oqinisekileyo. Ukusitheka okupheleleyo kunokwenza iNyanga ibonakale inombala wobhedu, ibomvu njengezitena, imdaka bumdaka okanye imnyama kakhulu. Umbala nokuqaqamba kwayo kuxhomekeke, ngokuyinxenye, kubungakanani bokukhanya kweLanga okudlula kwiatmosfera yoMhlaba; inkungu, amafu namasuntswana akwiatmosfera zinokuchaphazela ukukhanya okudlulayo. Ukusitheka okupheleleyo akuthethi ukuba iNyanga iyanyamalala, nangona kunokuba nzima ukuyibona ukuba umthunzi umnyama kakhulu okanye isibhakabhaka siqaqambile.
Ixesha lokusitheka ngokupheleleyo lelo xesha apho iNyanga yonke ingaphakathi kwi-umbra. Ngaphambi nasemva kwalo, ukusitheka okupheleleyo kuquka izigaba zokusitheka okuyinxenye, njengoko idiski yeNyanga ingena ize iphume kowona mthunzi umnyama. Njengomzekelo onomhla othile, ukusitheka kweNyanga ngokupheleleyo nge-31 Disemba 2028 kuboniswe njengexesha lokusitheka ngokupheleleyo elithatha imizuzu eyi-71.3. Ulandelelwano olupheleleyo lokusitheka luthatha ixesha elide kunelo xesha lisembindini, ngoko ke ababukeli abakwaziyo ukubona inxalenye yesiganeko kuphela basenokubona isigaba esithile sokusitheka okuyinxenye.
Izinto omawuzijonge xa ubukele
Kukhuselekile ukubukela ukusitheka kweNyanga ngeliso lenyama; ngokungafaniyo nokusitheka kweLanga, akufuneki zixhobo zokucoca ukukhanya ezikhuselayo. Iibinotyhulari zinokwenza kube lula ukuhlola utshintsho lomthunzi, kodwa akunyanzelekanga ukuba uzisebenzise. Fumana indawo onokuyibona kakuhle kuyo iNyanga uze ujonge ukuba iya kuba ngaphezu komda wendawo ohlala kuyo na ngexesha lesiganeko. Ikhathalogu yokusitheka inika iinkcukacha zokubonakala ngokweendawo, kanti ikhalenda yezigaba zeNyanga inokukunceda uhlole amaxesha ezigaba kwinyanga oyikhethileyo.
Xa ukusitheka kukwi-penumbra, jonga ukufiphala okuthe chu nokungalinganiyo, kunokuba ulindele umda ocace gca. Xa kusitheka ngokuyinxenye, jonga umda ogobileyo we-umbra njengoko uhamba unqumla idiski. Xa kusitheka ngokupheleleyo, nika amehlo akho ixesha lokuziqhelanisa nobumnyama, uze uqaphele ukuba iNyanga isenokugcina umbala neenkcukacha zayo endaweni yokuba ibe mnyama ngokufanayo. Le yantlukwano ibonakala ngakumbi xa ubukela ulandelelwano lonke kunokuba ukrobe esibhakabhakeni kube kanye: kukuhamba kancinci komthunzi okubonisa ukuba ukusitheka kukwi-penumbra, kuyinxenye okanye kuphelele.