ETIDOLI ShABU RUZ

ETIDOLI ShABU RUZ, lahzaeet, ki dar on markazi qursi Oftob hangomi harakati zohirii solonaash az rui ekliptika ekvatori osmoniro meburad. Dar ruzhoi etidol davomati ruz dar tamomi Zamin (gayr az nohiyahoi nazdiqutbi) ba davomati shab taqriban barobar ast. Dar natijai refraksiya va nisbatan kalon budani diametri kunjii Oftob davomati ruz yo shab az 12 soat ba yakchand daqiqa farq mekunadu bas. Nuqtae, ki dar on Oftob hangomi harakati khud az Nimkurai janubi ba Nimkurai shimoli ekvatorro meburad, nuqtai etidoli bahori va nuqtae, ki dar on Oftob hangomi harakati khud az Nimkurai shimoli ba Nimkurai janubi ekvatorro meburad, nuqtai etidoli tiramohi nomida meshavad. Azbaski fosilai vaqti bayni du guzarishi payopai Oftob az hamon yak nuqtai E. sh. r. (soli tropiki) bo davomati solhoi taqvimi muvofiqat namekunad, lahzahoi E. sh. r. sol ba sol nisbat ba sarshavii shaboruzii taqvimi digar meshavad. Lahzahoi E. sh. r. dar soli muqarrari nazar ba soli peshin 5 s 48 daq 46 son dertar va dar soli kabisa ba 18 s 11 daq 14 son peshtar ba vuqu mepayvandad; az in sabab E. sh. r. ba du shaboruzi payopay rost omadanash mumkin. Alhol (nimai duyumi a. 20) Oftob az nuqtai etidoli bahori 20 va 21 mart (in lahza sarshavii bahori astronomi dar Nimkurai shimoli hisob meshavad) va az nuqtai etidoli tiramohi boshad 23 sent. (sarshavii tiramohi astronomi dar Nimkurai janubi) meguzarad; sanahoi dodashuda az rui solshumorii nav va ogozi shaboruz bo vaqti Moskva doda shudaand.

Gipparkh (a. 2 to m.) muayyan kard, ki nuqtahoi E. sh. r. dar tuli eklipitka muqobili harakati solonai namoyoni Oftob ohista-ohista joy ivaz mekunad. In joyivazkuni dar natijai prosessiyai mehvari charkhzanii Zamin ba vujud meoyad va davrash taqr. 26000 sol ast. S. 1737 J. Bradley hodisai nutasiyai mehvari Zaminro kashf kard. Dar natijai nutasiya nuqtahoi E. sh. r. nisbat ba mavqei miyonaashon dar har 18,6 sol yak bor purra melappand (mavqei miyonai E. sh. r. tavassuti B joyivazkunii prosessioniashon muaiyan karda meshavad). Ba tagyiri mavqei nuqtahoi E. sh. r. tagyiri koordinatahoi osmonii jirmho vobaastaand. Dar fehristi sitoraho joi sitoraho baroi mavqei muayyani nuqtai etidoli bahori va davri takrorshavii in etidol doda meshavad.