TITLE: GCN CIRCULAR NUMBER: 17694 SUBJECT: GRB 150413A: Tautenburg observations DATE: 15/04/13 19:50:02 GMT FROM: Sylvio Klose at TLS Tautenburg S. Klose, S. Schmidl, B. Stecklum, A. Nicuesa Guelbenzu, D. A. Kann, and F. Ludwig (TLS Tautenburg) report: Tautenburg observed the afterglow of GRB 150413A (Markwardt et al., GCN 17688; Ivanov et al., GCN 17689; Tyurina et al., GCN 17690; Serino et al., GCN 17691; Schmalz et al., GCN 17692; Xu et al., GCN 17693) with the 1.34m Schmidt telescope under good weather conditions. At a mean time of 19:23 UT we measure a preliminary magnitude of R = 17.2 +/- 0.1, calibrated against the USNO B1 star #1618-0098185 (Xu et al.). Observations are continuing.