I try to concolve two spectra using the CONVOL function. I am a beginner with IDL... my first spectrum is: FLUX2000 = fltarr(800,800) openr, 1,'rotational_profile_2000.dat' for I = 0, 798 DO BEGIN readf, 1, format='(A3,F6.3,A6,F6.3)', STAR,XX,BLANK,YY FLUX2000(I,I) = [XX,YY] ENDFOR CLOSE, 1 my second spectrum is: FLUXGJ1097 = fltarr(402,402) openr, 1,'corr_gj_1097_final.dat' readf, 1, line readf, 1, line readf, 1, line for I = 0, 400 DO BEGIN readf, 1, format='(A10,E11.5,E11.5)', STAR,XX,YY FLUXGJ1097(I,I) = [XX,YY] ENDFOR CLOSE, 1 I try to convolve the t wo spectra using: CONVOL250 = CONVOL(FLUXGJ1097,FLUX2000,/NORMALIZE) but I get an error when running my program: IDL> ROTATIONAL_PROFILES % CONVOL: Incompatible dimensions for Array and Kernel. % Execution halted at: ROTATIONAL_PROFILES 146 /home/houdebine/papers/rotation_8/rotational_profiles_gj_1097.pro % $MAIN$ can someone help ? thank you