The passive modelocking of a cw rhodamine 6G dye laser over the spectral range 570 to 600 nm using 2-(p-dimethylaminostyryl)-benzthiazolylethyliodide (DASBTI) as the saturable absorber is reported. In a simple linear cavity with broad band reflecting mirrors, pulses as short as 520 fs were measured using standard second harmonic generation autocorrelation techniques.