HDU2
XTENSION= ‘IMAGE ‘ / Image extension
BITPIX = -64 / array data type
NAXIS = 2 / number of array dimensions
NAXIS1 = 4563 / wavelength pixel array
NAXIS2 = 2 / wavelength, R
PCOUNT = 0 / number of parameters
GCOUNT = 1 / number of groups
EXTNAME = ‘WAVE_ARRAY’ / extension name
UNIT = ‘Angstroem’ / unit of wavelength (vacuum)
END