Lewis & Short

observĭto, āvi, v. freq. a. [observo], to watch carefully, to note, observe (class.): Assyrii.. trajectiones motusque stellarum observitaverunt, Cic. Div. 1, 1, 2: deorum voces, id. ib. 1, 45, 102: omnia, App. Deo Socr. p. 52, 31; id. M. 8, p. 208, 17: caerimonias, Massur. Sabin. ap. Gell. 10, 15, 26.