On this day 146 years ago, on April 16, 1879 (March 25, 1879 in the lunar calendar), Danish astronomer Hans Rau was born. Hans Emil Rau (April 16, 1879-October 16, 1918) was a Danish astronomer. Law started astronomical observations while studying at the University of Copenhagen in Denmark. After graduating in 1906, he worked at the Treptuo Observatory in Berlin and later at the Hesholm Observatory in Copenhagen. Law's main academic contribution lies in his study of Mars and Jupiter. In addition, his research scope includes the measurement of constellations, variable stars, the color of planets, the observation of comets, sunspots and Saturn's moons. In 1900, he published a report on the orbital prediction of never-discovered supraneptunian objects. A crater on Mars is named after him. Died of Spanish flu in 1918. Comments: The loss of the Spanish flu is huge.