Iduna

Ngokomchazamkhathi, Iduna liyindikimba esemkhathini ezungeza umzulane, umzulane osichwe noma eye indikimba efana nayo, eyiduna ngokwayo. Amaduna ngokuvamile abizwa ngokuthi inyanga, okuyibizo elilsuselwa enyangeni yoMhlaba.

Kuzungezohlelo lwelanga, kunemizulane eyisithupha enamaduna, sewewonke amaduna akulemizulane, cishe angama-419, futhi wonke azungeza indikimba ethile. Izindikimba zimkhothi ezibizwa ogqayinyanga ngokuthi imizulane esichwe, zonke zinamaduna: Orcus, uNochoko, uNohunga, Quaoar, uNoviyo, Gonggong, kanye noNogxada.

Amagama asetshenziswayo
Iduna lokuqala elaziwayo kusukela endulo iNyanga, kodwa abanye babecabanga ukuthi inkanyezi noma "ngomzulane" kwaze kwaba ilapho uKhopenikasi ethula incwadi ethi De revolutionibus orbium coelestium ngonyaka we-1543. Amaduna ayangabhekwa njengesigaba kwaze kwaba ilapho uGalelio evubukula izinyanga zikaMkhulukhulwana. Naye uGalelio wayebiza lamaduna ngokuthi imizulane (Planetæ), kodwa abanye abavubukuli babekhetha amanye amagama ukuze bawahlukanise nezindikimba ayizungezayo.

Umuntu wokuqala owasebenzisa elithi "iduna" (satellite) ukuze achazise indikimba ezungeza enye kwaba ugqayinyanga waseJalimani uJohannes Kepler, encwajaneni yakhe ethi Narratio de Observatis a se quatuor Iouis satellitibus erronibus ("Isilandiso NgamaDuna Amane kaMkhulukhulwana Aqashelwe") ngonyaka we-1610. Leli gama walithatha kwelesiLathini elithi satelles, elisho inceku, inhlomeli, ngesiZulu ebizwa ngokuthi iDuna ehlezi iseduze neNkosi njengnsila yayo. Wasebenzisa elithi iDuna ngoba lezindikimba zihlezi zihambisana nomzulane eziwuzungezayo emkhathini.

NgesiZulu elithi iDuna liyafaneleka ukuze libhekisele ezindikimbeni ezisemkhathini ezizungeza umzulane, ukuze kugwemeke ukuthinziyela kwalelo elithi iNyanga, njengoba libuye lisho nomelaphi kanye nongoti. Bese elithi "isivoko" lona libhekisele kuma satellite wokuzakhela afana neSputnik okwaba yisivoko sokuqala esakhiwe abantu, ukuzungeza uMhlaba. Okusho ukuthi:
IDuna - natural satellite
Isivoko - artificial satellite 

Elithi iduna nelithi uMhlaba angasetshenziswa ngokushintshana njengoba cishe asho okufana, kodwa elithi iduna lihlanganisa zonke izindikimba ezizungeza imizulane kuhlanganisa neNyanga. 
Bese izindikimba ezakhiwe abantu ezizungeza indikimba esemkhathini zona zibizwe izivoko, okuyigama elisuselwa kwelithi imvoko elisho izindawo ezichazwa ngokuthi phecelezi 'satellite'. Ngakho elithi izivoko lisho izinguxa zokuzungeza indikimba esemkhathini

 Incasiselo yelithi iNyanga 

Awukho umkhawula ophansi ochaza ukuthi iNyanga liyinto enjani, njengoba noma iyiphi indikimba esemkhathini ezungeza umzulane wozungezohlelo lweLanga, noma incane kangakanani kuthiwa iNyanga, nakuba izindikimba ezincane eziyondweni zikaNomaxhama, zona zibizwa ngokuthi 'izinyangana'. Izinyangana nezinyanga zemihlatshana ezizungeza imihlatshana njengo-Dactyl, nazo kuthiwa izinyangana.

Umkhawulo ophezulu nawo uyathinziyela. Izindikimba ezimbili ziyachaziswa ngokuthi umzulane olukhonko kunokuthi umzulae neduna lawo. Imihlatshana efana no-90 Antiope nayo ibhekwa njengemihlatshana elikhonko, kodwa ayikaze yaba nencasiselo yokuthi iyini inyanga..