PRO head_twin, fitshead, wave, time

  ; extract keywords from Calar-Alto - twin header and decode
  ; to obtain wavelength and timeing arrays


  nwave =  FXPAR(fitshead, 'NAXIS1')
  wave   = fltarr(nwave)


  w0 =  FXPAR(fitshead, 'WAVE_0')
  w1 =  FXPAR(fitshead, 'WAVE_1')
  w2 =  FXPAR(fitshead, 'WAVE_2')
  w3 =  FXPAR(fitshead, 'WAVE_3')
  w4 =  FXPAR(fitshead, 'WAVE_4')
  FOR iw = 0,nwave-1 DO BEGIN
   wave(iw) = w0 + w1*iw + w2*iw*iw + w3*iw*iw*iw + w4*iw*iw*iw*iw
  ENDFOR
  wave = alog10 (wave) 

  ntime = FXPAR(fitshead, 'NAXIS2')
  time  = dblarr(ntime)

  mjd = FXPAR(fitshead, 'MJD-OBS')
  jd  = FXPAR(fitshead, 'JUL-DATE')
  ut0 =  FXPAR(fitshead, 'TIME_STA')
  dt =  FXPAR(fitshead, 'TIME_STE')

  j0 = floor(jd-0.5) - 2452000.
  ;   print,jd,j0,ut0,dt
 

  FOR it = 0,ntime-1 DO BEGIN
    time(it) = j0 + ( ut0 + dt*it ) / 86400.
  ENDFOR



END