Michele Rajna

Michele Rajna (September 28, 1854 – September 29, 1920) was an Italian mathematician and astronomer. He led astronomy at the University of Bologna for nearly two decades, publishing studies of eclipses, Earth's magnetic field, and geodetic astronomy. He was the director of the Observatory of Bologna from 1903 until his death.

Early life and education

Rajna was born in Sondrio, a city in the Kingdom of Lombardy–Venetia in the Austrian Empire, in 1854. He was the second-born son of Eugenio Paolo Rajna and Costanza Simonetta. His older brother Pio Rajna, born 1847, was an Italian philologist and literary critic who later served in the Senate of the Kingdom of Italy.

He attended Ghislieri College in Pavia, where he studied under astronomer Giovanni Schiaparelli at the Brera Astronomical Observatory. Rajna attended the University of Pavia, graduating with a doctorate in mathematics in 1878.

Career Upon graduating from the University of Pavia, Rajna joined the Brera Astronomical Observatory in 1878. In 1882, he was appointed Third Astronomer at the observatory and recognized for his mathematical work on Cartesian coordinate calculation by an invitation to join the Italian Geodetic Commission. He directed the Observatory of Bologna until his death, attempting unsuccessfully to have it transferred to Villa Aldini, a more suitable position on a nearby hill. A branch was later built in Loiano in 1933 by his successor, Guido Horn d'Arturo.

Rajna's work focused primarily on geodetic astronomy and the influence of solar activity on Earth's magnetic field. He found a method to graphically predict solar eclipses in 1891. He published a volume of logarithm tables to five decimals with Otto Müller through Hoepli Editore in 1883 which became one of the most commonly used computational aids in Italy for decades. It was republished in 1886 and again in 1891. Rajna also published a volume calculating the true geographical local time of any place in Italy. He was a member of the Italian National Academy.

After frequent periods of depression and illness, Rajna died on September 20, 1920, in Teglio, Italy.