PRO define_logw, wst, wdel, npix, w

  ; Define log lambda scale

  wen  = wst + npix * wdel
  wst = alog10 ( wst )
  wen = alog10 ( wen ) 
  dw  = (wen - wst) / (npix-1)  

  w=fltarr(npix)
  FOR i = 0,npix-1 DO BEGIN
  w(i) = wst + i*dw
  ENDFOR

END