Continuing EVN monitoring of HST-1 in the jet of M87

1INAF Istituto di Radioastronomia, Via Gobetti 101, 40129 Bologna, Italy 2National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, 181-8588 Tokyo, Japan 3Dipartimento di Fisica e Astronomia, Universita di Bologna, via Ranzani 1, I-40127 Bologna, Italy 4Instituto de Astrofisica de Andalucia, CSIC, Apartado 3004, 18080 Granada, Spain 5Washington University, St. Louis, MO 63130, USA 6Department of Physics, University of Trento, I-I38050 Povo, Trento, Italy 7Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352, USA 8Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510 Kanagawa, Japan 9Korea Astronomy and Space Science Institute (KASI), 776 Daedeokdae-ro, Yuseong-gu, Daejeon 305-348, Korea E-mail: kazuhiro.hada@nao.ac.jp