SHARONOV, VSEVOLOD VASILIEVICH

(b. St. Petersburg, Russia, 10 March 1901; d. Leningrad, U.S.S.R., 26 November 1964)

astronomy, geophysics.

Sharonov was the son of an Imperial opera singer. After graduating from the Gymnasium in 1918, he entered the Faculty of Physics and Mathematics of Petrograd University, from which he graduated only in 1926 after having served in the Red Army (1919–1924). From his youth Sharonov systematically conducted various astronomical observations, particularly of sunspots. While still a student he headed the section of solar research of the Russian Society of Amateurs of Astronomy and published instructions for conducting observations throughout the country; the results were then sent to Sharonov. He later recounted his experiences in Solntse i ego nablyudenia (“The Sun and Observations of It”: 1948, 1953).

As a graduate student (1926–1929) at the Leningrad Astronomical Institute (now the Institute of Theoretical Astronomy of the Soviet Academy of Sciences) Sharonov conducted a substantial part of his experimental work at the State Optical Institute in Leningrad and at the Pulkovo, Simeiz, Tashkent, and Leningrad University observatories. He defended his dissertation, on the theory and application of the photometric wedge, in October 1929. After working at the Tashkent observatory, he returned to Leningrad in 1930 as senior scientific worker. In 1932 Sharonov organized a photometric laboratory at the University of Leningrad (later the Laboratory of Planetary Astronomy) and carried out important projects on absolute photometry, on the colorimetry of the moon and planets, and on atmospheric optics. He devised and tested a number of photometric instruments for solving the problem of “visibility of distant objects and sources of light,” In December 1940 Sharonov defended his doctoral dissertation, on “indexes of visibility.”

From 1938 to 1941 Sharonov was a docent at Leningrad University, and from 1941 to 1944 he directed the astrophysics laboratory of the part of Leningrad University evacuated to Yelabuga, Tatar A.S.S.R. From 1944 he was professor at Leningrad University and, from 1951, director of its astronomical observatory.

Having studied the photometric wedge as the most convenient instrument for astronomical and geophysical observations, Sharonov worked from 1930 to 1936 at the Institute of Air Surveys on problems of aerophotometry applied to the aerial photographic survey of landscapes under various conditions of illumination and visibility. The original instruments that he developed for this purpose included an aeroexponometer, a sensitoscope, a sensitoscope, a haze measurer, an epsilometer, a diaphanometer, a universal wedge photometer, and a visual colorimeter. He used them in his photometrical laboratory and on expeditions to measure the transparency of the atmosphere and the visibility of distant objects. One group of his works was devoted to methods of spectrophotometry applied to the measurement of the color of the clear sky and to the determination of the solar light constant, which he found to be 135,000 lux.

Sharonov applied the absolute methods of photometry and colorimetry to study the lunar surface and the solar corona, which he observed successfully during seven total solar eclipses (1936–1963). He published tables and graphs of the variation in several photometric properties of more than 100 objects on the lunar surface. Comparing them with analogous investigations of rock and mineral specimens, he found confirming evidence of the “meteor-slag theory” advanced by his wife, N. N. Sytinskaya. According to this theory, almost all lunar rocks are covered with porous, spongy layers formed by the caking of particles that result from the fall of meteoric bodies, the latter being accompanied by explosions and sharp local rises in temperature.

Sharonov observed the oppositions of Mars at Tashkent in 1939, 1956, and 1958. His photometric and colorimetric research on the planets was summarized in Fotometricheskie issledovania prirody planet i sputnikov (“Photometric Research on the Nature of the Planets and Satellites”; 1954), Priroda planet (“The Nature of the Planets”: 1958), and Planeta Venera (“The Planet Venus”; 1965). He also developed the hypothesis that the surface of Mars is covered with limonite dust.

Sharonov was in charge of the Soviet study of noctilucent clouds for the International Geophysical Year in 1957–1959.

BIBLIOGRAPHY

I. Original Works. Sharonov’s more than 200 basic writings include “Issledovanie fotometricheskogo klina” (“Research on the Photometric Wedge”), in Trudy Tashkentskoi astronomicheskoi observatorii, 3 (1930), 84–100; “O sisteme i nomenklature astronomicheskikj svetovykh velichin” (“On the System and Nomenclature of Astronomical Light Quantities”), in Astronomicheskii zhurnal, 9 , nos. 1–2 (1932), 82–101; “O kharakteristikath otrazhatelnoy sposbnosti nebesnykh tel” (“On the Properties of the Reflecting Capacity of Heavenly Bodies”), Ibid, 11 , no. 5 (1934), 473–483; “On the Determination of the Absolute Reflectivity of the Moon and Planetary Surface,” in Trudy Astronomicheskoi osbservatorii Leningradskogo gosudarstvenogo universiteta, 6 (1936), 26–33; “A Simple Method of Checking the Purkinje Effect in Variable Star Observations,” in Variable Stars, 5 no. 3 (1936), 68–70; “Absolute Photographic Photometry of Saturn’s Disk,” in Poulkovo Observatory Circular, nos. 26–27 (1939), 37–51; “Opyt izmerenia absolyutnykh znacheny koeffitsientov yarkosit razlichnkh unchastkov lunnoy poverkhnosti” (“Experiment in Measuring the Absolute Values of the Coefficients of Brightness of VArious Parts of the Lunar Surface”) in Trudy Astronomicheskoi observatorii Leningradskogo gosudarstvennogo universiteta, 10 (1939), 28–60; and “Universalny klinovoy fotometr” (“Universal Wedge Photometer”) Ibid, 72–81 repr, in Uchenye zapiski Leningradskogo universiteta, no. 31, Math Ser., no. 3.

Later works are “Absolute Photographic Photometry and Colorimetry of Jupiter’s Disk at the Opposition of 1928,” in Poulkovo Observatory Circular, no. 30(1940), 48–64; “Problemy absolyutnoy fotometrii tel solnechnoy sistemy” (“Problems of Absolute Photometry of Bodies in the Solar System”), in Uchenzye zapiski Lennigradskogo Universiteta, no. 53 (1940), 5–36; “Osveshchennost v lunnye nochi” (“Illumination on Moonlit Nights”), in Astronomicheskie zhurnal, 20 no. 1 (1943), 21–33; Vidimost dalekikh predmetov i ogney (“The Visibility of Distant Objects and Sources of Light”; Moscow-Leningrad, 1944); lzmerenie i raschet vidimosti dalekikh predmetov (“Measurement and Calculation of Visibilites of Distant Objects”; Moscow-Leningrad. 1947); Mars (Moscow-Leningrad, 1947); “Diafanoskop, ego teroira, issledovanie i primenenie” (The Diaphanometer, Its Theory Research, and Use”), in Trudy Glavnoi geofizicheskoi observatorii imeni A. I.Voeikova (1948), no 11, 73–110; and “Opyt absolyutnoy fotometrii serebristykh oblakov” (“Experiment on the Absolute Photometry of Noctilucent Clouds”), in Nauchy byuleten Leningradskogo universiteta, no. 22 (1948), 5–16.

See also “Issledovanie otrazhatelnoy sposobnosti lunnoy poverkhnosti” (Research on the Reflecting Capacities of the Lunar Surface”), in Trudy Astronomicheskoi observatorii Leningradskogo gosudartvennogo universiteta, 16 (1952),114–154,written with N.N.sytinskaya:“‘ Yavlenie Lomonosov’ i ego znachenie dlya astronomii”(“‘ Lomonosov’s phenomenon’ and Its Importance for astronomy”),in astrnomicheskii zhurnal,29 ,no.6(1952),728–737; “problema fotometricheskikh bablyudeny lunnykh zatmeny” (“The Problem of Photometric Observations During Lunar Eclipes”). in Vestnik Leningradskogo Universiteta, no. 2 (1953), 47–61; “Fotometricheskie issledovania prirody planet i sputnikov” (“Photometric Researchs on the Nature of Planets and Satellites”), in Uspekhi astronomicheskikh nauk, 6 (1954), 181–249, which has a bibliography of 256 titles; and “Fotometricheskie i kolorimetricheskie sravenia poverkhnosti Marsa s obraztsami limonita i gornykh porod krasnotsvetnykh tolshch” (Photometric and Colorimetric Comparisons of the Surface of Mars with Specimens of Limonite and of Rock From the Red Layers”), in lzvestiya Komissii po fizike planet Astrosoveta Akademii nauk SSSR, no. 2 (1960), 30.

II. Secondary Literature. See the obituary in Astronomicheskii tsirkulyar, Byuro astronomicheskikh soobshchenni, Akademiya nauk SSSR, no. 311 (1964); V. A. Bronshten, “Leningradky issledovatel planet” (“Leningrad Investigator of the Planets”), in Zemlya i vselenaya, no. 5 (1969), 70–70; Izvestiya Komissii po fizike planet Astrosoveta Akademii nauk SSSR, no. 5 (1965), 105–111; L. N. Radlova, in Astronomicheskii Kalendar na 1966 (Moscow, 1965), 242–245, with portrait; and Uchenye zapiski Leningradskogo universiteta no. 328 (1965), 175–177.

P. G. Kulikovsky