Possible design of a FITS ASCII table containing WCS information

Here follows a draft schematic for the contents of the FITS header:
XTENSION= 'TABLE   '           / ASCII table extension
BITPIX  =                    8 / number of bits per data pixel
NAXIS   =                    2 / always 2 for a FITS table
NAXIS1  =                  xxx / number of chars needed to describe columns
NAXIS2  =                  yyy / number of rows of WCSs stored in the table
PCOUNT  =                    0 / required FITS extension keyword
GCOUNT  =                    1 / required FITS extension keyword
TFIELDS =                   nn / Number of columns in the table

EXTNAME = 'DEI_WCS'            / This table describes a group
DATE    = 'dd/mm/yy'           / Date of construction of grouping table
CTIME   = 'WkD CcYy Mon Dt Hr:Mn:Ss TZn' / Time of construction of table

COMMENT This document does not attempt to describe any particular
COMMENT ordering for these columns.  In real applications the columns
COMMENT need not be in any particular order.

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'CCDPOS'             / In which position was this CCD?

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'AMPPOS'             / In which position is this amplifier?

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'CTYPE1'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'CTYPE2'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'F10.3'              / Fortran 77 format of column
TTYPEn  = 'CRPIX1'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'F10.3'              / Fortran 77 format of column
TTYPEn  = 'CRPIX2'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'CRVAL1'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'CRVAL2'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'CDELT1'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'CDELT2'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'PC001001'           / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'PC002001'           / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'PC001002'           / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'PC002002'           / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'CUNIT1'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'CUNIT2'             / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'RADECSYS'           / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'F13.6'              / Fortran 77 format of column
TTYPEn  = 'EQUINOX'            / WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'F17.9'              / Fortran 77 format of column
TTYPEn  = 'MJD_WCS'            / UCO/Lick keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'A8'                 / Fortran 77 format of column
TTYPEn  = 'DOMAIN'             / DEI_WCS keyword

TBCOLn  =                    x / First character in column
TFORMn  = 'E16.13'             / Fortran 77 format of column
TTYPEn  = 'PROJP1'             / WCS keyword
COMMENT It is not clear that we will need the PROJPn WCS keywords,
COMMENT but it is clear that they could be stored in this fashion.

END
The header is padded with ASCII blanks such that it consists of a positive integer multiple of 2880 bytes (36 card images of 80 characters).

The semantics of the keywords/columns which are not derived from the draft WCS standard document are described in this data dictionary.


Back to the WCS table idea page.
Back to the DEIMOS home page.
Steve Allen <sla@ucolick.org>
$Date: 1996/08/19 06:11:11 $