ɪn diːtˈeɪld stˈʌdiz, ðə dᵻɹˈɛkʃənəl ɹᵻflˈɛktəns pɹˈɑːpɚɾiz ʌv ɐstɹənˈɑːmɪkəl bˈɑːdiz ɑːɹ ˈɔfən ɛkspɹˈɛst ɪn tˈɜːmz ʌvðə fˈaɪv hˈæpk pɚɹˈæmɪɾɚz wˌɪtʃ sˈɛmaɪɛmpˈɪɹɪkli dᵻskɹˈaɪb ðə vˌɛɹɪˈeɪʃən ʌv ælbˈiːdoʊ wɪð fˈeɪz ˈæŋɡəl, ɪŋklˈuːdɪŋ ɐ kˌæɹɪktɚɹaɪzˈeɪʃən ʌvðɪ ˌɑːpəzˈɪʃən ɪfˈɛkt ʌv ɹᵻɡˈɑːlɪθ sˈɜːfɪsᵻz.
In detailed studies, the directional reflectance properties of astronomical bodies are often expressed in terms of the five Hapke parameters which semi-empirically describe the variation of albedo with phase angle, including a characterization of the opposition effect of regolith surfaces.