Series include: 1) Scientific works (346 folders, 1894-1959). There are books and articles in astrobiology, photometrics, optics and optics of atmosphere, astrophysics, some problems of general astronomy, solar and lunar eclipses, on general problems of science. 2) From earlier period of activity the collection keeps the papers "O prilozhenii fotograficheskogo metoda Kapteina k opredeleniiu parallaksa iarkikh zvezd" ("On the Application of the Kaptein Method to Measure the Parallax of Bright Stars", 1907); "Primenenie svetofiltrov k izucheniiu poverkhnosti Marsa" ("The Application of the Light Filters for Observing the Mars Surface", 1911); "Mertsanie zvezd, ego zapis' i vosproizvedenie" ("Twinkling of Stars. Its Recodering and Reproduction", 1913); texts of his talks: "dispersii v mezhduzvezdnom prostranstve" ("Dispertions in Interstellar Space", 1896); "Novejshie issledovaniia po perenosu zarodyshej zhizni cherz mirovoe prostranstvo" ("Recent investigations of Possibility to Move Grems of Life through the Universe", 1925); Many works are devoted to the state, prospects and development of astrobiology. Texts of talks and records of discussions concerning the extraterrestrial life (1952; 1953); papers "Geotsentrizm v sovremennoj biologii" ("Geocentric Theory and Modern Biology", 1957); "O tungusskoj katastrofe 1908 g. i o sputnikakh planety Mars" ("About Tunguss Catastrohe of 1908 and the Mars Satellites", 1959); "O nauchnom znachenii zapuska iskusstvennogo sputnika Zemli" ("On the Scientific Value of the Launch of the Artificial Satellite of the Earth", 1959). 3) Drafts and calculations to scientific works; tables, descriptions of devices, technical documentation, photo picutres of various spectra, bibliography to different problems. 4) Programmes and notes to lecutres on astrophysics (1919-1927); diaries and journals of observations and measuements during astronomical expeditions of 1925 and 1936. 5) Reviews of works and activity of other persons (in general 40 folders). Among others V.A. Ambartsumian, N.A. Kozyrev, V. G. Fesenkov. 6) An article "Johann Kepler" (1946), an obituary "Serjei Pavlovich Gazenap" (1937), memories about A.A. Belopol'skii (1924-1954), N.N. Kalitin (1959), N.A. Morozov (1924-1954). 7) Popular articles to newspapers and magazines, autobiographical notes. 8) Materials about administrative activity (40 folders of 1918-1959); reports about scientific activity of Tikhov (1943-1944); documents related to the expeditions to Tashkent, Crimie, Ural (1920-1922); Kil'din island (1922-1925); Ivanovo (1945) and their preparations. Documents about activity in the Astronomical Council of the Academy of Sciences and in the Commission on the Physics of Planet at it, in the Commission on the Preparation and Conducting of the Observations of Solar Eclipse in 1941, about his activity in the Main Astronomic Observatory (GAO) and its Alma-Ata Department, in the All-Union Astronomo-Geodezic Sco. as chairman of its Kazakhstan branch, in heliotechnical Presidium of the Academy of Sciences of Kazakhstan, and others. Correspondences with editors concerning publication of his works, that with foreign astronomical societies (1937-1959). 9) Biographical materials (21 folders of 1856-1960). Albums with drawings of Tikhov's grandfather, artist G.A. Zubkovich (1856-1880); records (1950-1955); lists of publications (1928-1959); personal documents, diploma of scientific degrees and state awards, press-cuttings, reviews from abroad. 10) Photo pictures (33 folders of 1870-1960) including those of himself and his relatives (1870-1940s); photos from the Khar'kov conference of 1949 on the planets hysics and astronomical expidition of 1936. 11) Personal correspondence (437 folders of 1900-1960). Among correspondents there are A.A> Bogomolets, K.E. Voroshilov, A.F. Ioffe, L.A. Kassil', T. P. Kravets, O.A. Mel'nikov, N.A. Morozov, L.A. Orbeli, E.N. Pavlovskii, M.F. Subbotin, V.G. Fesenkov, A.L. Chizhevskii, G.A. Shain. 12) Papers by other persons (63 folders of 1903-1958). Articles, dissertations, journals and photos from expiditions by I.S. Actapovich, L.S. Berg, N.I. Idel'son, E.L. Krinov, G.N. Neujmin, B.V. Numerov, N.G. Ponomarev, and some others.