Nutasiya

Nutasiya (lotini nutatio — lappish) dar mekhanika, harakati lappandai jismi sakht hangomi dar atrofi mehvari khud davr zadani jism; in guna harakat dar mehvari davrzanii khususii jism ba vuchud meoyad va har qadare ki jism bo surati kalon davr zanad, basomadi lappishi nutasionii on hamon qadar ziyod, amplitudaash kam mesha­vad. Nutasiya bo presessiya dar yak vaqt ba amal meoyad. Hangomi Nutasiya kunji bayni mehvari davrzanii khususii jism va mehvare, ki dar atrofi on pre­sessiya ba amal meoyad, tagyir meyobad. Nazariyai Nutasiya ba muodilahoi dinamikii Eyler asos yoftaast.

Nutasiyai astronomi dar lappishhoi khurdi mehvari Zamin zuhur meyobad. Ba ha­rakati shaboruzii Zamin quvvahoi kashishi Oftob va Moh tasir merasonand. Mehvari davrzanii shabo- ruzii Zamin tamoyuli khudashro nisbat ba ekliptika tagyir nadoda ha- rakatashro davom medihad, zero quvvahoi presessionii Oftob va Moh niz tagyir yofta meistand. Nutasiyai davrzanii mehvari Zaminro soli 1737 astronomi anglis J. Bradley kashf kardaast. Davri in guna lashshshhoi nutasioni ba 18,6 sol, yane ba dav­ri girehhoi madori harakati Moh barobar ast. Dar sferai osmon qutb ellipsi nutasionie mekashad, ki nimtirhoyash 9″21 va 6″86 meboshad. Qimati Nutaisyaro soli 1953 astronomi amerikoi E. Vulard daryoftaast.