  <!--
  In the case of this file there are two kinds of WCS.
  One kind gives the transformations from CCD pixels to the final
  coordinate systems.
  The other kind gives the transformations from amplifier pixels
  to its CCD coordinates.
  None of these is the transformation from FITS pixels to the final
  coordinate system.

  The transformation from FITS pixels to the final coordinate systems
  is computed by concatenating other WCS transformations from FITS
  pixels to amplifier pixels (which are created in real-time as part
  of the pixel reading and descrambling) with the static WCS
  transformations that are described in this file.

  The transformation from FITS pixels to amplifier pixels depends on
  prescan and binning factors which can vary from one readout to the
  next.  The image acquisition software must determine the FITS to
  amplifier transformation and concatenate it with the amplifier to
  final transformation before writing it to the header of a FITS
  IMAGE.
  -->
  <!ELEMENT     wcs
    (
	WCSDEPs?,
	WCSAXES?,
	CRPIXj* ,
	CRVALi* ,
	CDi_j*  ,
	WCSNAME?,
	CUNITi* ,
	CRDERi* ,
	CSYERi* ,
	CTYPEi* ,
	PVi_m*  ,
	CelCooSys?
    )
  >
    <!ATTLIST   wcs             Owner           IDREF   #REQUIRED >
    <!ATTLIST   wcs             version         CDATA   " "       >
  <!ELEMENT     WCSAXES         EMPTY >
    <!ATTLIST   WCSAXES         value           CDATA   #REQUIRED >
  <!ELEMENT     CRPIXj          EMPTY >
    <!ATTLIST   CRPIXj          j               CDATA   #REQUIRED >
    <!ATTLIST   CRPIXj          value           CDATA   "0."      >
  <!ELEMENT     CRVALi          EMPTY >
    <!ATTLIST   CRVALi          i               CDATA   #REQUIRED >
    <!ATTLIST   CRVALi          value           CDATA   "0."      >
  <!ELEMENT     CUNITi          EMPTY >
    <!ATTLIST   CUNITi          i               CDATA   #REQUIRED >
    <!ATTLIST   CUNITi          value           CDATA   " "       >
  <!ELEMENT     CDi_j           EMPTY >
    <!ATTLIST   CDi_j           i               CDATA   #REQUIRED >
    <!ATTLIST   CDi_j           j               CDATA   #REQUIRED >
    <!ATTLIST   CDi_j           value           CDATA   #REQUIRED >
  <!ELEMENT     CRDERi          EMPTY >
    <!ATTLIST   CRDERi          i               CDATA   #REQUIRED >
    <!ATTLIST   CRDERi          value           CDATA   "0."      >
  <!ELEMENT     CSYERi          EMPTY >
    <!ATTLIST   CSYERi          i               CDATA   #REQUIRED >
    <!ATTLIST   CSYERi          value           CDATA   "0."      >
  <!ELEMENT     CTYPEi          EMPTY >
    <!ATTLIST   CTYPEi          i               CDATA   #REQUIRED >
    <!ATTLIST   CTYPEi          value           CDATA   " "       >
  <!ELEMENT     PVi_m           EMPTY >
    <!ATTLIST   PVi_m           i               CDATA   #REQUIRED >
    <!ATTLIST   PVi_m           m               CDATA   #REQUIRED >
    <!ATTLIST   PVi_m           value           CDATA   #REQUIRED >
  <!ELEMENT     WCSNAME         EMPTY >
    <!ATTLIST   WCSNAME         value           CDATA   #REQUIRED >
    <!ATTLIST   WCSNAME         comment         CDATA   #IMPLIED >
  <!ELEMENT     WCSDEPs         EMPTY >
    <!ATTLIST   WCSDEPs         value           CDATA   #REQUIRED >
  <!ELEMENT     CelCooSys
    (
	LONPOLE,
	LATPOLE,
	EQUINOX?,
	MJD_OBS?,
	RADESYS?
    )
  >
  <!ELEMENT     LONPOLE         EMPTY >
    <!ATTLIST   LONPOLE         value           CDATA   #REQUIRED >
  <!ELEMENT     LATPOLE         EMPTY >
    <!ATTLIST   LATPOLE         value           CDATA   #REQUIRED >
  <!ELEMENT     EQUINOX         EMPTY >
    <!ATTLIST   EQUINOX         value           CDATA   #REQUIRED >
  <!--
  MJD-OBS is global to an observation and should agree for all
  versions of WCS
  -->
  <!ELEMENT     MJD_OBS         EMPTY >
    <!ATTLIST   MJD_OBS         value           CDATA   #REQUIRED >
  <!ELEMENT     RADESYS         EMPTY >
    <!ATTLIST   RADESYS         value           CDATA   #REQUIRED >

<!--
########################################################################
-->

<!--
Here follow some locally defined general entities.
-->
<!ENTITY        CD2ident        SYSTEM  "CD2ident.xml"  >
<!ENTITY        CD2flipX        SYSTEM  "CD2flipX.xml"  >
<!ENTITY        CD2flipY        SYSTEM  "CD2flipY.xml"  >
<!ENTITY        CD2flipXY       SYSTEM  "CD2flipXY.xml" >