set output './vband_a.ps' 
set term postscript color enhanced 'Helvetica,18'  
set grid 
set key top right 
set ylabel 'Transmission ' 
set xlabel 'Wavelength (Angstroms) ' 
set title 'Johnson-Cousins V-band filter ' 
plot [4500:7000][0.0:1.1]     './bess_v_pass.dat'     using 1:2  with lines lt 1 lc 1 lw 3 t 'Bessell V'  ,   './equiv_v_pass.dat'    using 1:2  with lines lt 2 lc -1 lw 3 t 'equiv rect'   
set output 
quit 
