FXADDPAR: Required NAXIS keyword not found #2

IDLで主にHerschel reference survey のデータで起きる現象

（I often see this error message when I treat HRS data.）

エラーの詳細はこちら
（If you want to know more detail about this error see here）

ヘッダーを見ると（In the image header, there is）

XTENSION= 'IMAGE   '           / Java FITS: Wed Nov 10 18:15:02 GMT 2010
BITPIX  =                  -64
NAXIS   =                    2 / Dimensionality
NAXIS1  =                   99
NAXIS2  =                   99
PCOUNT  =                    0 / No extra parameters
GCOUNT  =                    1 / One group
LONGSTRN= 'OGIP 1.0'           / The OGIP long string convention may be used.
COMMENT This FITS file may contain long string keyword values that are
COMMENT continued over multiple keywords.  This convention uses the  '&'
COMMENT character at the end of a string which is then continued
COMMENT on subsequent keywords whose name = 'CONTINUE'.
          -------------- Herschel Structure Data--------------------
          Following fields are private to the structure of the
          Java object this HDU is representing.
EXTNAME = 'image   '           / name of this HDU
CLASS___= 'herschel.ia.dataset.ArrayDataset' / java representation
INFO____= 'Image   '
DATA____= 'herschel.ia.numeric.Double2d' / java Data
QTTY____= 'Jy/beam '           / Unit of the data
          -------------- Herschel Parameter Data--------------------
          All actual parameter names are converted to FITS compliant
          conventions. Note that the HIERARCH comments contain the
          appropriate key mapping
META_0  =                   99 / []
META_1  =                   99 / []
CRPIX1  =                 49.5 / [] WCS: Reference pixel position axis 1, uni&
COMMENT t=Scalar
CRPIX2  =                 49.5 / [] WCS: Reference pixel position axis 2, uni&
COMMENT t=Scalar
CRVAL1  =             185.4787 / [] WCS: First coordinate of reference pixel
CRVAL2  =                4.474 / [] WCS: Second coordinate of reference pixel
CDELT1  =   -0.001666666666667 / [] WCS: Pixel scale axis 1, unit=Angle
CDELT2  =    0.001666666666667 / [] WCS: Pixel scale axis 2, unit=Angle
CTYPE1  = 'RA---TAN'           / WCS: Projection type axis 1, default="LINEAR"
CTYPE2  = 'DEC--TAN'           / WCS: Projection type axis 2, default="LINEAR"
EQUINOX =               2000.0 / [] WCS: Equinox, unit=Duration
CROTA2  =                  0.0 / [] The Rotation angle
HIERARCH  key.META_0='naxis1'
HIERARCH  key.META_1='naxis2'
HIERARCH  key.CRPIX1='crpix1'
HIERARCH  key.CRPIX2='crpix2'
HIERARCH  key.CRVAL1='crval1'
HIERARCH  key.CRVAL2='crval2'
HIERARCH  key.CDELT1='cdelt1'
HIERARCH  key.CDELT2='cdelt2'
HIERARCH  key.CTYPE1='ctype1'
HIERARCH  key.CTYPE2='ctype2'
HIERARCH  key.EQUINOX='equinox'
HIERARCH  key.CROTA2='crota2'
END

解決方法（solution）

IDL> sxdelpar,h2,'XTENSION'

IDL> sxaddpar, h2, 'SIMPLE', 'T', before='BITPIX'

何をしているか（What you did with these lines）

'XTENSION'を消して（delete 'XTENSION' and）

'SIMPLE=T'を追加 （add 'SIMPLE=T'）