pro slshi_sbsp,stks,shftsl,ny1,ny2 ; routine to apply the spatial shifts of the image as a function ; of spectral pixel number to Stokes I only for purposes of finding ; the drift correction as called by thermd_sbsp.pro. When applied, these ; shifts rectify the images so that spectral variation is strictly ; along the spectral pixel direction. This process is known as removal ; of the spectral skew. ; INPUTS: stks - Stokes spectral images (spectral,along slit,4) ; shftsl - previously computed shifts to be applied ; ny1,ny2 - range of pixels along slit to shift (avoiding ; defects near the ends) ; OUTPUT: stks ; working arrays next power of two larger in length nyy = sizeof_sbsp(stks,2) nxx = sizeof_sbsp(stks,1) ; full spectral dimension of data for i = 0,20 do begin np2 = 2^i if np2 gt nyy then begin ntrp = np2 goto, kilroy endif endfor kilroy: sltvar = fltarr(ntrp) ; slit variation extended to next power of 2 nyb = ny2-ny1+1 ;for kk = 0,3 do begin ; loop over Stokes parameters kk = 0 for i = 0,nxx-1 do begin sltvar(*) = 0. sltvar(0:nyb-1) = stks(i,ny1:ny2,kk) ; extend the array rather than apodize sltvar = extend_sbsp(sltvar,0,nyb-1) fftera = fft(sltvar,-1) fftera = xshift_sbsp(fftera,-shftsl(i)) sltvar = float(fft(fftera,1)) stks(i,ny1:ny2,kk) = sltvar(0:nyb-1) endfor ;endfor end