Thian-bûn-ha̍k sī leh gián-kìu Tē-kîu ê tāi-khì-tsân guā-kháu-bīn ê tshenn-thé ham hiān-siōng (phenomena) ê kho-ha̍k, tshīunn tshenn, hi̍k-tshenn, tn̂g-bué-tshenn, gîn-hô, iah sī ki̍k-kng (aurora), ú-tīu bî-pho puē-kíng hok-siā (cosmic microwave backgroond radiation), tíng-tíng. Gián-kìu ê tiōng-tiám khah tsùn-būn tshenn-thé ê ián-huà, bu̍t-lí-ha̍k, huà-ha̍k, ham ūn-tōng (motion), kap ú-tīu tsái-īunn tsoo-sîng, huat-tián ê ú-tīu-lūn. Kuan-tshik thian-bûn-ha̍k (observational astronomy) mā ē-tit īng lâi kiám-giām bu̍t-lí-ha̍k ê ki-pún lí-lūn, pí-lūn kóng it-puann siong-tuì-lūn. Kuan-tshik--tio̍h ê thian-bûn hiān-siōng ē-tit īng lí-lūn thian-thé bu̍t-lí-ha̍k (astrophysics) lâi kái-sueh.
- Tsit phinn sī uì Hô-ló-pah-kho(Holopedia) ê : "Thian-bûn-ha̍k" kái lâi ê. Guân-pún ê tsok-tsiá tshiánn khuànn i êpian-tsi̍p li̍k-sú.