Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
항성일은 별의 위치가 같은 날을 의미합니다.hangseongil-eun byeol-ui wichi-ga gat-eun nal-eul uimi-hamnida.A sidereal day refers to a day when the position of the stars is the same.