Mean power spectral density computed from 5000 50 ms-images for Capella on 2011 Oct. 16 using data from a single V-groove. The color-scale has been adjusted by discarding the zero-frequency peak (not visible in the image). The fitted peak positions are superposed as dashed white lines only on the left part of the image for better visibility. The (telluric) absorption line appearing at spectral channel number 147 is exactly vertical, showing that the distortion in the image has been effectively corrected. At least 27 different peaks are clearly visible out of the 36 expected ones.