In 1883 he became a professor in Prague and was the ninth director of the Klementinum observatory. There, on 27 November 1885, he took the first known photograph of a meteor. He set up observing stations in Prague and Jena (to observe the Andromedids shower of that year, which turned out to be very intense), and caught a 7mm-long trail on a plate in Prague.
In collaboration with Friedrich Küstner, he made measurements of the height of the pole. During their investigations they also discovered polar motion, the movement of the Earth's polar axis relative to the crust.