Keywords: Fig1553.jpg Optical spectrum of the BL Lac object PG 1553+11 obtained with VLT + FORS1 Flux calibrated dereddened upper panel and normalized lower panel spectrum Other examples of optical spectra of BL Lacs can be fout at the web pages http //www oapd inaf it/zbllac/ en Image Fig1553 jpg Original Umpload 10 aug 2006 Rfalomo BL Lac Objects |