Txhawm rau saib lub ntuj tsis yog nrog lub qhov muag liab qab, tab sis dhau los ntawm lub tsom iav tiag tiag, ntau tus muaj lub siab xav. Tab sis tsis yog txhua tus tau txais mus rau qhov yuav cov khoom kim. Txhawm rau yuav lub tsom iav raj thiab tsis txhob poob siab nyob rau hmo ntuj, tsis tas siv nyiaj ntxiv, koj yuav tsum xam seb lub tsom iav raj yog dab tsi thiab seb lawv sib txawv li cas.
Thaum xaiv tsom iav, xyuam xim rau lub tsom iav tsom hom (refractor, reflector, catadioptric), mount (alt-azimuth, equatorial, auto-aiming (khoos phis tawj), Dobson), lub ntsej muag lens thiab focal ntev. Thiab tam sim no hais txog tag nrho cov no hauv cov lus yooj yooj yim thiab to taub.
Refractors (lens) thiab tsom iav (daim iav) tsis txawv ntau hauv nqe, tab sis lawv muaj ntau tus lej sib txawv. Nws yog qhov yooj yim los soj ntsuam ob qho tib si thaj av thiab thaj chaw hauv qhov refractor, thiab nyob rau hauv lub zog duab saib yog tig rau sab hauv, yog li nws yuav tsis xis saib cov khoom hauv av. Tsis tas li ntawd reflectors yog qhov muag qis dua qhov tsis cuam tshuam, yog li lawv xav tau lub taub loj dua. Lwm qhov tsis zoo ntawm qhov pom kev zoo yog tias lawv tsis ua siab ntev tsis zoo txav tsis zoo, thiab yog li ntawd lawv yuav tsum tau kho kom tsis tu ncua (teeb tsa daim iav) thiab ntxuav. Tab sis reflectors kuj muaj lub meej mom - tsis zoo li cov refractor, lawv tsis muaj chromatic aberrations (uas peb pom zoo li halos dawb lias).
Catadioptric (iav-tsom iav) tsom iav tsom iav muaj qhov loj tshaj plaws ntawm qhov ntev tshaj plaws ntawm qhov loj me me, uas yog, lawv tau cog lus me me. Hauv lawv, koj tuaj yeem saib lub hli, ntiaj teb, lub hnub qub, nrog rau nebulae thiab galaxies uas muaj qhov kev nplij siab zoo ib yam. Tab sis nws cov nqi yuav twb tau ntau dua li cov reflectors thiab refractors.
Tam sim no hais txog cov nce. Alt-azimuth yog qhov yooj yim tshaj plaws, tsis tas yuav muaj kev txawj tshwj xeeb, coj tsis hnyav, pheej yig thiab siv tau txawb heev. Tab sis nws muaj qhov cuam tshuam tseem ceeb: ntawm lub roob, koj tuaj yeem tsuas saib cov khoom ntawm lub zenith (koj tsis tuaj yeem taug qab cov khoom txav txav, tsuas yog kho dua tshiab thiab nthuav tawm) thiab nws tsis raug yoog rau astrophotography.
Lub vaj huam sib luag ntawm cov kab hluav taws xob yooj yim dua: tom qab tsom mus rau ntawm ib qho khoom, koj tuaj yeem coj nws kev taug kev nrog tsuas yog ib tus kov, thiab nws tseem yooj yim dua kom pom cov khoom ploj ntawm nws. Thiab vim tias muaj qhov cuav tawm tsam, koj tuaj yeem txuas lub koob yees duab digital thiab coj cov duab ntawm qhov chaw. Tab sis xws li lub mount nyhav dua thiab ntau dua tus nqi.
Khoos phib tawj (hluav taws xob, pib kev taw qhia) - siv tau yooj yim (tsuas yog thawj lub tsom iav hluav taws xob tso yog xav tau), muaj lub hauv paus los ntawm qhov koj tuaj yeem xaiv cov khoom, muaj cov chaw taws teeb tswj thiab muaj peev xwm hloov kho cov ntaub ntawv. Txhawm rau ua haujlwm nrog lub tsom iav ntawm saum lub roob, tsis muaj kev paub txog lub hnub qub ntawm lub hnub qub, vim nws yuav pom thiab tsom rau tus kwv uas nws muaj nyob hauv nws lub chaw khaws ntaub ntawv.
Dobson yog chav ua noj pem teb tsim los soj ntsuam cov khoom sab nraum peb lub hnub ci (galaxies, nebulae). Nws ruaj khov thiab loj heev. Tab sis koj yuav tsis tuaj yeem saib qhov chaw ze nrog kev pab ntawm ib lub roob.
Muaj ob yam ntxiv los xav txog thaum xaiv tsom iav tsom.
Qhov siab kawg uas siv tau ntawm lub tsom iav ntev yog suav raws li txoj kab uas hla ntawm lub lens muab khoo los ntawm ob. Tab sis nws yuav tsum tau coj mus rau hauv tus account tias qhov loj dua lub lens lub ntsej muag, qhov ci dua thiab pom tseeb daim duab yuav. Hauv focal ntev cuam tshuam rau cov magnification thiab saib kev nplij siab. Qhov ntev ntawm qhov focal ntev, nws yuav yooj yim dua rau kev soj ntsuam, txij li txo qis kev pom tseeb ntawm lub qhov muag yuav pom zoo txo qhov chaw pom thiab xis nyob.
