Until the October Revolution, the official time in Moscow corresponded to GMT+02:30:17 (according to the longitude of the Astronomical Observatory of Moscow State University). In 1919 the Council of People's Commissars of the RSFSR introduced the system of time zones in the country, while Moscow was assigned to the second administrative time zone, the time of which should correspond to GMT+02:00. Other zones east of the 37.5° meridian to Arkhangelsk, Vologda, Yaroslavl, Kostroma, Ivanovo, Vladimir, Ryazan, Tula, Lipetsk, Voronezh and Rostov-on-Don were also included in the second belt.