First column: examples of z > 2 quasars classified as STAR by the BOSS pipeline. The overall shape of the spectrum is similar to the spectrum of F stars. Second column: examples of stars identified as QSO by the BOSS pipeline. Strong absorption lines or wiggles in the spectrum can mimic quasar features. Third colum: examples of z > 2 quasars for which the BOSS pipeline provides an inaccurate redshift estimate that must be corrected during the visual inspection. The pipeline is confused by the strong absorption lines. The spectra were boxcar median smoothed over 5 pixels.