The Observatory in the years of T. Banachiewicz's management (19191954) 

In 1919 the post of the director of the Observatory
and the chair of astronomy have been taken by Prof.
Tadeusz Banachiewicz (18821954). Banachiewicz
accomplished his studies in astronomy at the Warsaw
University and obtained also there, in 1904, his degree
of the candidate of sciences; then he had two scientific
stays, one with K. Schwarzschild in Götingen and the
other in Pulkovo Observatory (Russia). In the years
19081909 Banachiewicz was a younger assistant at the
Warsaw Observatory; in 1910 he passed an examination to
the M. Sc. degree in astronomy at the Moscow University.
Then  until 1915 he was an assistant at the Engelhardt
Observatory in Kazan, where he made his excellent series
of heliometric observations of the Moon. In the years
19151918 Banachiewicz was initially an assistant at the Dorpat
(now Tartu) University, and later he obtained  as
Master of Science in astronomy (since 1917)  the post
of an associated  and finally  of an extraordinary
professor. His 35 years' activity at the Cracow Observatory resulted in many interesting achievements. He furnished the Observatory with larger observational instruments and, under his management, the Observatory became an international center of research in the field of eclipsing binaries and started publishing its own ephemeris. Banachiewicz founded in 1925 a scientific journal Acta Astronomica and was its editor in Cracow until his death. He published about 240 papers on astronomy, mathematics, mechanics, geodesy and geophysics; his scientific correspondence contains some 15000 letters. In celestial mechanics one can find the BanachiewiczOlbers method of determining parabolic orbits. Since 1925 Banachiewicz developed a kind of matrix calculus, called by him the cracovian calculus. Cracovians are matrices that are multiplied "column by column" and their algebra is radically different from that of matrices. Cracovian operations essentially facilitated arithmometric astronomical computations as well as some theoretical considerations. Owing the cracovians Banachiewicz discovered general formulae of spherical polygonometry, and simplified considerably the algorithm of the least squares method and the practice of solution the systems of linear equations. The cracovian calculus has found its numerous applications in spherical astronomy, celestial mechanics, determining orbits, geodesy and even in the static of building constructions. It is worth to note that the first orbit of Pluto has been determined in the Cracow Observatory. Banachiewicz had also in his scientific output many interesting ideas and practical implementations of observational methods. Let us note here e.g. his chronocinematographic camera (1927) for recording eclipses of the Sun and his method of geodedic application of positional observations of the Moon for connecting, over seas, continental triangulation networks. Banachiewicz was also a pioneer of radio astronomy in Poland. In a time he acted as a vicepresident of the International Astronomical Union and of the Baltic Commission for Geodesy, he was also the president of the Commission 17 of the IAU (Motion and Figure of the Moon), he had three doctorates honoris causa, he was also a member of many scientific societies. A number of Polish astronomers descended from Banachiewicz's laboratory (J. Witkowski, J. Mergentaler, E. Rybka, K. Kordylewski and S. Piotrowski). In 1920s Banachiewicz organizes a station if the Cracow Observatory on the Mt. Lubomir near Cracow. That station has been damaged by nazi troops in 1944. In 1953 Banachiewicz obtained from the military administration Fort Skala, a present abode of the Cracow Observatory. Banachiewicz died in 1954 