Tanthauzo ndi Ntchito ya Sextant mu Kuyenda
Kuyenda panyanja kwakhala gawo lofunika kwambiri pa chitukuko cha anthu kwa zaka zikwi zambiri. Kuyambira nthawi zakale mpaka nthawi yamakono, kufufuza zapanyanja kwathandiza anthu kufufuza dziko lapansi, kuchita malonda, ndi kukhazikitsa mgwirizano pakati pa makontinenti. Chida chimodzi chomwe chakhala ndi gawo lofunika kwambiri pakuyenda panyanja ndi sextant. M'nkhaniyi, tikambirana za sextant, momwe imagwirira ntchito, ndi ntchito yake yayikulu pakuyenda.
Kumvetsetsa Sextant
Sextant ndi chida choyezera ngodya pakati pa zinthu ziwiri, nthawi zambiri pakati pa chinthu chakumwamba monga dzuwa, mwezi, nyenyezi, kapena dziko lapansi ndi mlengalenga. Dzina lakuti "sextant" limachokera ku liwu lachilatini lakuti "sextans," kutanthauza "gawo limodzi mwa magawo asanu ndi limodzi," chifukwa mzere wa chidacho nthawi zambiri umaphimba madigiri 60, kapena gawo limodzi mwa magawo asanu ndi limodzi a bwalo. Sextant ndi kusintha kwa quadrant yakale ndi astrolabe, zomwe zimagwiritsidwanso ntchito poyesa ma angles akumwamba.
Sextant inayamba kupangidwa m'zaka za m'ma 18 ndipo kuyambira pamenepo yakhala chida chofunikira kwambiri pakuyenda panyanja. Kupangidwa kwa sextant nthawi zambiri kumanenedwa kuti kunapangidwa ndi amuna awiri, John Hadley wa ku England ndi Thomas Godfrey wa ku United States, omwe adapanga chida ichi paokha cha m'ma 1731.
Momwe Sextant Imagwirira Ntchito
Mfundo yaikulu ya sextant ndi kuwunikira kowala. Chida ichi chili ndi magalasi awiri: galasi la horizon ndi galasi lolozera. Galasi la horizon limakhalabe lofanana ndi horizon, pomwe galasi lolozera limatha kusunthidwa kuti ligwirizane ndi chinthu chakumwamba chomwe chikuwonedwa.
Njira zoyambira zogwiritsira ntchito sextant ndi izi:
1. Kusintha Koyamba: Onetsetsani kuti sextant yayikidwa bwino. Wosintha ayenera kuyang'ana magalasi ndikuwonetsetsa kuti ali bwino.
2. Kuyang'ana Zinthu: Kudzera mu telesikopu yomwe ili pa sextant, woyendetsa sitima amaona kuwala kwa dziko lapansi ndi zinthu zakuthambo pamwamba.
3. Kusuntha Galasi Lolozera: Galasi lolozera limasunthidwa m'njira yoti chithunzi cha chinthu chakumwamba chikhale chofanana ndi thambo.
4. Kuwerenga Ngodya: Pambuyo poti chinthu chakumwamba ndi thambo lakumwamba zalumikizidwa kudzera mu telesikopu, ngodya pakati pa mizere iwiri ya maso imawerengedwa pa sikelo pa bow ya sextant.
5. Kukonza Zolakwika: Pali zolakwika zosiyanasiyana zomwe zingakhudze kuwerenga kwa ngodya, monga zolakwika za index, zolakwika zofala, ndi zolakwika za refraction, zomwe ziyenera kuganiziridwa ndi kukonzedwa.
Poyesa ngodya imeneyi panthawi inayake, woyendetsa sitimayo angagwiritse ntchito matebulo owonera zakuthambo kuti adziwe malo a sitimayo.
Ntchito ya Sextant mu Kuyenda
Sextant imagwiritsidwa ntchito kupereka chidziwitso chokhudza malo a sitimayo panyanja, komwe zizindikiro za dziko lapansi sizingakhalepo kapena sizingaoneke. Sextant ili ndi ntchito zingapo zazikulu zoyendera:
1. Kudziwa Latitude
Poyesa ngodya pakati pa dzuwa pachimake (malo okwera kwambiri kumwamba) ndi mlengalenga pogwiritsa ntchito sextant, oyendetsa sitima amatha kudziwa latitude ya sitimayo. Dzuwa likafika pamalo ake apamwamba kwambiri, ngodya imeneyi imadziwika kuti zenith angle. Ngodya yomwe yawonedwa imayerekezeredwa ndi matebulo a zakuthambo kuti idziwe latitude.
2. Dziwani Kutalika (Longitude)
Kudziwa kutalika kwa malo n'kovuta kwambiri kuposa latitude, chifukwa kumafuna kuyeza nthawi molondola. Pogwiritsa ntchito sextant poyesa ngodya pakati pa chinthu china chakumwamba ndi horizon panthawi inayake, komanso pogwiritsa ntchito matebulo a nthawi (monga Nautical Almanac), oyendetsa sitima amatha kudziwa kutalika kwa sitimayo. Mu nthawi isanafike ma chronometers olondola, kudziwa kutalika kwa malo kunali vuto lalikulu pakuyenda.
3. Dziwani Zinthu Zakumwamba
Ma sextant amathandizanso kuzindikira nyenyezi, mapulaneti, ndi zinthu zina zakuthambo zomwe zingagwiritsidwe ntchito ngati zizindikiro zoyendera. Podziwa malo a zinthu zakuthambo nthawi iliyonse, oyendetsa sitima amatha kupanga mamapu akuthambo ndikujambula malo a zombo panyanja.
4. Kupewa Zoopsa Zokhudza Kuyenda Panyanja
Podziwa bwino malo enieni a sitimayo, oyendetsa sitima amatha kusamala kuti apewe zoopsa monga miyala yam'madzi, zombo zina, ndi madzi osaya. Sextant imathandiza kukonzekera maulendo otetezeka komanso osavuta.
5. Kuphunzitsa ndi Kuphunzitsa
Masiku ano, sextant nthawi zambiri imagwiritsidwa ntchito pophunzitsa anthu za kayendedwe ka sitima komanso pophunzitsa anthu. Ngakhale kuti ukadaulo wamakono monga GPS walowa m'malo mwa sextant m'machitidwe a tsiku ndi tsiku, kumvetsetsa momwe sextant imagwirira ntchito kumakhalabe gawo lofunika kwambiri pa maphunziro a oyendetsa sitima ndi oyendetsa sitima. Imagwira ntchito ngati chothandizira ngati ukadaulo wamakono walephera.
Ubwino ndi Kuipa kwa Sextants
Kelebihan
1. Osadalira Ukadaulo Wamakono: Ma sextant safuna mabatire, ma satellite, kapena ma wailesi kuti agwire ntchito, zomwe zimapangitsa kuti azidalirika pakagwa ngozi.
2. Kulondola Kwambiri: Ndi luso ndi chidziwitso choyenera, sextant ingapereke zotsatira zolondola kwambiri podziwa malo otseguka panyanja.
3. Kulimba: Yopangidwa ndi zipangizo zapamwamba kwambiri, sextant ndi yolimba ndipo imatha kupirira nyengo zovuta za m'nyanja.
Kusowa
1. Kugwiritsa Ntchito Movuta: Kumafuna luso lapadera ndi maphunziro kuti mugwiritse ntchito bwino.
2. Kudalira Nyengo: Nyengo yoipa monga mitambo yokhuthala kapena chifunga ingasokoneze kuwona zinthu zakuthambo.
3. Malire a Nthawi: Miyeso nthawi zambiri imayenera kutengedwa nthawi zinazake, monga pamene dzuwa lili pachimake, zomwe zingachepetse kugwiritsa ntchito kwake.
Mapeto
Sextant ndi chida chosatha komanso chofunikira kwambiri choyendetsera sitima chomwe chathandiza oyendetsa sitima zapamadzi kwa zaka mazana ambiri. Ngakhale kuti ukadaulo wamakono wapereka zida zosavuta komanso zachangu zoyendetsera sitima, kudziwa momwe sextant imagwiritsidwira ntchito kumakhala kofunikira kwambiri komanso kofunikira, makamaka ngati njira ina pazochitika zadzidzidzi. Kaya ndi paulendo wamalonda, wankhondo, kapena wosangalatsa, sextant ikadali chizindikiro cha luso ndi kupirira m'dziko la kuyenda panyanja.
