Analemma

In astronomy, an analemma ( /ˌænəˈlɛmə/; from Greek ἀνάλημμα "pedestal of a sundial") is a curve representing the changing angular offset of a celestial body (usually the Sun) from its mean position on the celestial sphere as viewed from another celestial body (usually the Earth). The term is used when the observed body appears, as seen from the viewing body, to move in a way that is repeated at regular intervals, such as once a year or once a day. The analemma is then a closed curve, which does not change.