.help mkheader Aug90 noao.artdata
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NAME
mkheader - Append/replace image header
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USAGE
mkheader images headers
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PARAMETERS
.ls images
List of images in which header information is to be added or modified.
.le
.ls header = "artdata$stdheader.dat"
List of images or header keyword data files.  If the list is shorter
than the input image list then the last entry is repeated.
If an image is given then the image header
is copied.  If a file is given then the FITS format cards are copied.
This only applies to new images.   The data file consists of lines
in FITS format with leading whitespace ignored.  A FITS card must begin
with an uppercase/numeric keyword.  Lines not beginning with a FITS
keyword such as comments or lower case are ignored.  The user keyword
output of \fBimheader\fR is an acceptable data file.
.le
.ls append = yes
Append to existing keywords?  If no then the existing header is replaced.
.le
.ls verbose = no
Verbose output?
.le
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DESCRIPTION
The image headers in the list of input images may be replaced or appended
with information from images or data files specified by the \fIheader\fR
parameter list.  If the header list is shorter than the list of images
to be modified the last header file is repeated.  Depending on the
value of the \fIappend\fR parameter, new parameters will be appended
or replace the existing image header parameters.

A header keyword data file consists of lines of FITS format cards.
Leading whitespace is ignored.  Lines not recognized as FITS cards
are ignored.  A valid FITS card is defined as beginning with a keyword
of up to 8 uppercase, digit, hyphen, or underscore characters.  If
less than 8 characters the remaining characters are blanks.  The
ninth character may be an equal sign but must be immediately followed
by a blank.  Such value cards should be in FITS format though no
attempt is made to enforce this.  Any other ninth character is also
acceptable and the line will be treated as a comment.  Note that this
way of recognizing FITS parameters excludes the case of comments
in which the first 8 characters are blank.  The reason for allowing
leading whitespace and eliminating the blank keyword case is so that
the long output of \fBimheader\fR may be used directly as input.

Header files are also used by several of the tasks in the artificial
data package with a standard default file "artdata$stdheader.dat".
To edit image headers also see \fBhedit\fR.
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EXAMPLES
1. Add some standard keywords from a file to an image.

.nf
    ar> type myheader
    # MY header list
    INSTRUME= 'bspec mark II'		/ B Spectrograph
    LENS    =                  3	/ Lens number
    FOCRATIO=                5.2        / Focal ratio
    ar> mkheader *.imh myheader
.fi

2. Copy an image header.

    ar> mkheader new dev$pix append-

3. Edit the image header with a text editor and replace the old header
with the edited header.

.nf
    ar> imheader myimage l+ > temp
    ar> edit temp
    ar> mkheader myimage temp append-
.fi
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SEE ALSO
hedit, mkobjects, mknoise, mk1dspec, mk2dspec
.endhelp
