Ukusitheka kwenyanga akuhlali kubukeka ngendlela efanayo. Ngezinye izikhathi iNyanga iba buthuntu kancane kuphela; ngezinye izikhathi ijika elimnyama libonakala sengathi liluma ingxenye yobuso bayo; kanti ngezinye izikhathi yonke idiski yenyanga iba bomvu ngokufiphele. Umehluko uncike endleleni iNyanga edlula ngayo esithunzini soMhlaba. Amagama amathathu—okusitheka kwenyanga okusemaphethelweni esithunzi, okuyingxenye nokuphelele—achaza ukuthi ingakanani iNyanga engena engxenyeni emnyama kakhulu yaleso sithunzi, ebizwa ngokuthi i-umbra. Ukuqonda ukuma kwalezi zinto kwenza kube lula ukubona okwenzekayo, ikakhulukazi lapho ushintsho lungabonakali kahle. Ukuze uthole izinsuku zokusitheka, izikhathi zokuqala nokuphela kwezigaba, ubude besikhathi kanye nezindawo lapho kubonakala khona, sebenzisa ikhathalogi ebukhoma yokusitheka kwenyanga.
UMhlaba wenza izinhlobo ezimbili zesithunzi
ILanga liwumthombo wokukhanya omkhulu, alilona iphuzu nje. Ngakho uMhlaba wenza indawo emaphakathi lapho ukukhanya kwelanga okuqondile kuvinjelwa khona, kanye nendawo engaphandle lapho kuvinjelwa khona ingxenye yokukhanya kwelanga kuphela. Isithunzi esimaphakathi yi-umbra; isithunzi sangaphandle esingacacile kangako yi-penumbra. Umngcele uncike ekumeni kwezinto: ku-penumbra, umuntu oseNyangeni usengabona ingxenye yeLanga, kuyilapho ku-umbra uMhlaba ulivala lonke iLanga.
Ukusitheka kwenyanga kungenzeka kuphela lapho kunenyanga egcwele, lapho uMhlaba uphakathi kweLanga neNyanga. Kodwa izikhathi eziningi inyanga egcwele idlula ngaphezu noma ngaphansi kwesithunzi soMhlaba ngoba umjikelezo weNyanga utsheke ngo-5.14 degrees uma uqhathaniswa ne-ecliptic, okuyindiza yomjikelezo woMhlaba ozungeza iLanga. Ukusitheka kwenzeka lapho inyanga egcwele iba seduze nendawo lapho lezi zindiza zemijikelezo zihlangana khona. Umhlahlandlela wezigaba zeNyanga uchaza ukuthi kungani isigaba seNyanga sincike endaweni ekuyo uma iqhathaniswa neLanga noMhlaba; uhlobo lokusitheka lona luncika endleleni iNyanga edlula ngayo esithunzini soMhlaba.
Okusemaphethelweni esithunzi: ukufiphala okusabalele nokungabonakali kahle
Lapho ukusitheka kwenyanga kusemaphethelweni esithunzi, iNyanga idlula ku-penumbra yoMhlaba kodwa ingangeni ku-umbra. Akukho mngcele omnyama ocacile onqamula idiski yenyanga. Kunalokho, ingxenye ethile noma yonke iNyanga ithola ukukhanya kwelanga okuqondile okuncane kancane, bese ibonakala ifiphele, ngokuvamile ohlangothini oluseduze ne-umbra. Kulula ukungakuqapheli lokhu, ikakhulukazi ekuqaleni noma ekupheleni komcimbi, lapho kuyiqephu elincane kuphela leNyanga eliku-penumbra.
Yingakho ukusitheka kwenyanga okusemaphethelweni esithunzi kungaba ukuhleleka kwezinto kwangempela, okungalinganiswa, kodwa kungabonakali kuhlaba umxhwele ngeso lenyama. Kungase kubonakale kangcono esithombeni kunalapho ubheka ngokushesha, kodwa ukulungisa okuzenzakalelayo kokuchayeka kwekhamera kunganxephezela ukufiphala kwenze kube nzima ukuqhathanisa izithombe. Uma uthatha izithombe, gcina indlela yokuthwebula nezilungiselelo zokuchayeka kungashintshi bese uziqhathanisa nesithombe osithathe ngaphambi noma ngemva kokusitheka. Ukusitheka kwenyanga okusemaphethelweni esithunzi akusho ukuthi iNyanga idlula efwini noma ukuthi ishintsha ukukhanya kwayo; kuwukuncipha kancane kancane kokukhanya kwelanga okubangelwa ukuthi uMhlaba uvale iLanga ngokwengxenye uma kubukwa useNyangeni.
Ngokwesibonelo, ukusitheka kwenyanga okusemaphethelweni esithunzi kwango-20 February 2027 kubhalwe ukuthi kuthathe imizuzu engu-241. Leso sikhathi eside asisho ukuthi iNyanga izobonakala imnyama ngokusobala amahora amane: ukufiphala kuyashintsha kancane kancane, futhi ingxenye ejule kakhulu ye-penumbra iyona okungenzeka ibonakale kunomngcele wayo wangaphandle ofiphele kancane. Ikhalenda likaFebruary 2027 elibukhoma linikeza izikhathi eziqondile zezigaba zeNyanga zaleyo nyanga, kanti ikhathalogi yokusitheka inikeza imininingwane yomcimbi.
Okuyingxenye: ijika elimnyama liqhubekela ngaphesheya kweNyanga
Ukusitheka kwenyanga okuyingxenye kwenzeka lapho ingxenye ethile yeNyanga ingena ku-umbra, kanti enye ingxenye isala ngaphandle kwayo. Uphawu olubonakala ngokucacile kakhulu yisifunda esimnyama kunazo zonke esinomngcele oyijika, esikhula sinqamule ubuso beNyanga. Umngcele we-umbra uyijika ngoba uMhlaba uyindilinga; ukusitheka kwenyanga kwasiza ababukeli ukuba babone leso simo kudala ngaphambi kokuba imikhumbi-mkhathi ikwazi ukuthwebula uMhlaba usemkhathini.
Isithunzi asiyona into eqinile ebekwe phezu kweNyanga, futhi umngcele waso awucijile ngokuphelele. Ukukhanya kwelanga okudlula emkhathini woMhlaba kwenza umngcele ungacaci. Noma kunjalo, umehluko phakathi kwengxenye ekhanyayo engaphandle kwe-umbra nengxenye efiphele engaphakathi kuyo uvame ukubonakala kakhulu kunokufiphala kokusitheka kwenyanga okusemaphethelweni esithunzi. INyanga ayinyamalali lapho kusitheka ingxenye yayo, futhi ingxenye eseyingaphandle kwe-umbra iyaqhubeka ikhanyiswa ukukhanya kwelanga okuqondile.
Ukuthi ingakanani iNyanga embozekayo kuyashintshashintsha kuye ngendlela ukusitheka okwenzeka ngayo. Ukudlula okungajulile ku-umbra kushiya inotshi encane emnyama kuphela; ukudlula okujule kakhulu kungamboza ingxenye enkulu yediski kodwa kungayimbozi yonke. Ukuhlukanisa izinhlobo kusekelwe endaweni yeNyanga esithunzini, hhayi ekutheni umbukeli uyakwazi yini ukubona umcimbi. Umkhathizwe wendawo, ukukhanya kwemini, isimo sezulu nendawo iNyanga ekuyo esibhakabhakeni konke kuyayithinta indlela ebonakala ngayo. Ideshibhodi yedolobha efana ne-ikhasi leNyanga laseLondon ibonisa izikhathi zokuphuma nokushona kweNyanga endaweni, ukuphakama kwayo, i-azimuth nesimo sezulu, okungasiza ekuhleleni ukubuka isibhakabhaka ngokujwayelekile.
Okuphelele: iNyanga ingena yonke ku-umbra
Ngesikhathi sokusitheka kwenyanga okuphelele, yonke idiski yenyanga idlula ingene ku-umbra yoMhlaba. INyanga isabonakala ngoba umkhathi woMhlaba ugoba okunye ukukhanya kwelanga kungene esithunzini. Njengoba lokho kukhanya kudlula emkhathini, amaza amafushane okukhanya okuluhlaza asakazeka kakhulu kunawabomvu. Ngakho-ke ukukhanya okusele okufinyelela eNyangeni kuvame ukuba bomvu noma kube owolintshi, bese ubuso beNyanga bukubuyisela kubabukeli abaseMhlabeni.
Inkulumo edumile ethi “inyanga yegazi” ibhekisela kulokhu kubonakala kwayo ibomvu okungenzeka, hhayi ohlotsheni oluhlukile lokusitheka noma kumbala othile oqinisekile. Ukusitheka okuphelele kungayenza ibukeke njengethusi, ibomvu njengezitini, insundu ngokufiphele noma imnyama kakhulu. Umbala nokukhanya kwayo kuncike ngokwengxenye ekutheni kungakanani ukukhanya kwelanga okuhlunga kudlule emkhathini woMhlaba; inkungu, amafu nezinhlayiya ezisemkhathini kungathinta ukukhanya okudlulayo. Ukusitheka okuphelele akusho ukuthi iNyanga iyanyamalala, nakuba kungase kube nzima ukuyibona uma isithunzi simnyama kakhulu noma isibhakabhaka sikhanya.
Isikhathi sokusitheka ngokuphelele yisikhathi lapho yonke iNyanga ingaphakathi ku-umbra. Ngaphambi nangemva kwaso, ukusitheka okuphelele kuhlanganisa nezigaba zokusitheka okuyingxenye, njengoba idiski yenyanga ingena iphinde iphume esithunzini esimnyama kakhulu. Njengesibonelo sosuku oluthile, ukusitheka kwenyanga okuphelele kwango-31 December 2028 kubhalwe ukuthi kwaba nemizuzu engu-71.3 yokusitheka ngokuphelele. Ukusitheka konke kuthatha isikhathi eside kunaleso sikhathi esiphakathi, ngakho ababukeli abakwazi ukubona ingxenye ethile yomcimbi kuphela bangase babone isigaba esiyingxenye.
Okufanele ukubheke ngesikhathi ubuka
Kuphephile ukubuka ukusitheka kwenyanga ngeso lenyama; ngokungafani nokusitheka kwelanga, akudingi izihlungi zokuzivikela. Izibonakude ezimbili ezincane zingasiza ukuhlola isithunzi esishintshayo, kodwa awuphoqelekile ukuzisebenzisa. Thola indawo lapho iNyanga ibonakala kahle khona bese uhlola ukuthi izobe ingaphezu komkhathizwe wendawo yangakini ngesikhathi somcimbi. Ikhathalogi yokusitheka inikeza ulwazi lokubonakala kwezindawo ezahlukene, kanti ikhalenda lezigaba zeNyanga lingakusiza uhlole izikhathi zezigaba zenyanga oyikhethile.
Lapho ukusitheka kusemaphethelweni esithunzi, bheka ukufiphala okuqhubekayo nokungalingani kunokulindela umngcele ocijile. Lapho kusitheka ingxenye, bheka umngcele we-umbra oyijika uhamba unqamula idiski. Ngesikhathi sokusitheka ngokuphelele, nika amehlo akho isikhathi sokujwayela ubumnyama, bese uqaphela ukuthi iNyanga ingase igcine umbala nemininingwane esikhundleni sokuba mnyama ngokulinganayo. Lo mehluko ubonakala kahle uma ubuka ukulandelana komcimbi kunokubheka isibhakabhaka kanye kuphela: ukuhamba kancane kwesithunzi yikho okuveza ukuthi ukusitheka kusemaphethelweni esithunzi, kuyingxenye noma kuphelele.