EQUATORIAL SUNDIAL Russian patent published in 2003 - IPC

FIELD: instruments determining time by the Sun. SUBSTANCE: equatorial sundial has base which upper part includes plane parallel to plane of celestial equator and is fitted with elements fixing dial. Summer time gnomon is installed on upper surface of dial, in center of circumference of reading scale of summer time and lower surface of dial carries winter time gnomon mounted in center of circumference of reading scale of winter time. Center of circumference of reading scale of winter time is displaced with reference to center of circumference of summer time by value ( 0.5-1.0 )R where R is radius of circumference of reading scale of winter time. Reading scale of summer time has displacement diagram of reading point of local time relative to shadow cast by gnomon. EFFECT: capability of time reading in winter season, increased convenience of sundial handling and accuracy of local solar time reading. 5 cl, 5 dwg