NAME

esohdr -- translate ESO WFI raw headers for use with MSCRED

SYNOPSIS

ESO WFI raw headers are modified for use with MSCRED. This includes renaming all HIERARCH keywords, renaming the extension names, setting the observation type, setting all the geometry keywords, and setting a first astrometric solution.

USAGE

esohdr input

PARAMETERS

input

List of raw ESO multiextension (MEF) files to be modified. This task knows if a file has been previously modified so it is ok to include such files in a wildcard template.

querytype = yes

The current headers do not contain an indication as to the type of observation (zero, dark flat, or object). If this parameter is yes then a query will be made for the observation type.

namps = 1

Number of amps per CCD.

ntransient = 2

Number of bad transient columns. This number of columns following the prescan will be excluded from the TRIMSEC keyword. Note that DATASEC will still include the all CCD columns.

wcsdb = "esowfi$lib/wcs.db"

Database file containing the world coordinate system (WCS) information.

redo = no

Redo a previously modified header? If no then only files without the ESOHDR keyword will be operated upon. If yes then those files previously modified will be modified again. This skips the step which transforms the HIERARCH keywords since these were removed the first time. It also skips the RA keyword update.

obstype

This is the parameter used to query for the observation type if querytype is yes. This parameter only allows a selection from a set of choices which may be abbreviated. The value set for this parameter does not matter since it is queried. However, if the parameter is specified explicitly on the command line then there will be no query and the value will be used for all files.

DESCRIPTION

ESOHDR provides a header translation of raw WFI multiextension format (MEF) files so that the MSCRED task may be used. The translation includes renaming the HIERARCH keywords, adding keywords used by MSCRED, and setting an initial astrometric solution.

The task first checks for the keyword ESOHDR in the primary header to determine if the task has been run previously. Depending on the redo parameter files with the keyword will be ignored or the translation will be done again excluding the steps of renaming the HIERARCH keywords and converting the RA keyword from degrees to hours.

The HIERARCH convention keywords are converted to simple FITS keywords for access by IRAF and other software not supporting the HIERARCH format. The renaming consists of removing the first three words (HIERARCH, ESO, and the next word), concatenating the rest of the words, and truncating (if necessary) to 8 characters. For example,

    "HIERARCH ESO INS FILT NAME" --> "FILTNAME"

IRAF supports an inheritance convention for merging the primary header keywords with the extension keywords. This means IRAF tasks that operate on extensions will see a complete set of keywords automatically. The ESOHDR task sets the INHERIT keyword to provide this feature.

Next the observation type is queried if desired. This is done because the current headers don't include information allowing the automatic identification of the observation type. The observation type is set in the primary header keyword FRAMTYPE.

Each extension is modified to provide the keywords used by MSCRED. The geometry of the readout -- the size, direction, location of overscan and prescan, etc. -- is determined from other information in the header. Also the extension names are modified to a shorter and more convenient form. The names are "im#" where # is the CCD number (1-8).

In the last step the RA keyword, which is given in degrees in the raw ESO primary header, is converted to hours, which is what is expected by MSCRED. This is only done once. The RA and DEC keywords are then used to define the tangent point of the world coordinate system for the mosaic exposure. The other terms of the linear WCS are set from an astrometric solution specified in a database file. A default database file is provided.

EXAMPLES

1. Set the headers for a set of raw ESO files.

    cl> esohdr *.fits

REVISIONS

ESOHDR - Vexternal package

First release.

SEE ALSO

mscred package documentation