Jesuit astronomer, born Moravia August 20, 1719; died Heidelberg, Germany, April 16, 1783. He taught mathematics at the University of Heidelberg, constructed and took charge of astronomical observatories at Mannheim and Schwetzingen, and conducted scientific research in Paris and Saint Petersburg. He was a member of numerous learned societies. His claims of having discovered stars, evidently due to an optical illusion, caused much controversy. He wrote several astronomical treatises.