High Quality Content by WIKIPEDIA articles! The SK-42 reference system also known as the Krasovsky ellipsoid, is a coordinate system established in the Soviet Union in 1942 as Systema koordinat (Russian: 1942 ), and provides parameters which are linked to the geocentric Cartesian coordinate system PZ-90. It was used in geodetic calculations, notably in military mapping and determining state borders. Feodosy Nikolaevich Krasovsky was a Russian and later Soviet astronomer and geodesist. He was born in Galich. In 1900 he graduated from the Mezhevoy (land surveying) Institute in Moscow; in 1907 he began working as a lecturer there.