set term png set size 1.8 set grid set out '2-3.png' S = (16-1)*3600 + (47+2.2)*60 + 10 t(x) = S + x B=(24*3-6)*3600 E=(24*3+6)*3600 set xdata time set format x "%H:%M" set title \ 'log10 ( voltage at PV panel / 0.1 mV ) on 2/3 July 2006, Kravi hora, Brno' set xlabel 'Local solar time, being 57.8 min less then CEST' plot [B:E] '30-.txt' using ($1 + S):(log10($2)+4) ,\ 'casy2.tab' using (24*2*3600+$1):($2+1) with impulses title \ 'Sunset and Sun at -6, -12, -15 degrees and vice versa'