Date of Birth: 04/04/1867
Place of birth: St. Petersburg
Alexander Ivanov (4 (16) April 1867, St. Petersburg - November 23, 1939) - Russian (Soviet) astronomer astrometrist, corresponding member of the Academy of Sciences of the USSR (1925). In 1889 he graduated from St. Petersburg University and was left with him to prepare for a professorship. Since 1890, at the invitation of AF Bredikhina worked at the Pulkovo observatory observer on a large vertical circle in 1901-1911 - in the main chamber of weights and measures. In 1908-1929 years - professor of St. Petersburg (Leningrad) University, in 1913-1919 - as director of the University Observatory, which has established regular publication of its proceedings. In the years 1918-1919 - Rector of the University of Petrograd. In 1919-1930 years - the director of the Pulkovo Observatory. Since 1930 - Deputy Director of the All-Union Scientific Research Institute of Metrology them. Mendeleev.
The main scientific works are devoted to celestial mechanics and practical astronomy. According to observations on a large vertical circle at Pulkovo was three directories absolute declination of stars, investigated the variability of Pulkovo latitude. He studied the resonant cases of motion of small planets under the influence of the gravitational field of Jupiter. He studied the motion of the minor planet Gerda (Observations 1872-1934 years). More investigated the precession of the Earth is not completely spherical under the influence of gravity of the Moon and the Sun, was the amount of compression of the Earth, equal to 1: 297.2, which is close to the modern value. Based on the analysis of the measurements of gravity in many areas of the earth surface concluded that the asymmetry of the Northern and Southern Hemispheres. Much has been done to improve Soviet-time service information. Author of textbooks on the general, spherical, practical and theoretical astronomy. One of the founders of the Russian Astronomical Society and its chairman in 1906-1910, 1913.