RAGtime 13 is the latest of a series annually held in Opava, Czech Republic, on subjects related to Relativistic Astrophysics. It will be held in the period 14th-16th September, 2011 in Opava. The conference room is located in the lounge of the building"Hradecka 17", Opava. The organizational backup is provided by The Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, in the framework of Research Project MSM 4781305903 and Centre for Theoretical Astrophysics LC06014.