Basic Information on puthd

Task: puthd
Purpose: Change the value of or add a single header item
Categories: utility

        PUTHD is a MIRIAD task to add or modify an item in the "header"
        of an image or uv dataset.  The item CANNOT be an array or any
        other complex data structure, it must be a single entity.  To
        modify such complex data structures, specialized programs are
        available.
 

Key: in
        The name of an item within a data set.  This is given in the
        form as in the example:
           puthd in=dataset/item

Key: value
        The value to be placed in the item.  Note only single values can
        be given, no arrays.
 
        An optional second units argument can be given to convert the
        value before the item is stored.  Possible units are "degrees",
        "arcminutes", "arcseconds", "time", "hours", "hms", and "dms"
        (with mininum match).  Times are given in the standard Miriad
        form and are stored as Julian dates.  Angular units are
        converted if necessary and stored in radians.  bpa, being the
        exception, is stored in degrees, but value is still interpreted
        as radians unless you specify "degrees" as the unit.

Key: type
        The data type of the argument.  Values can be 'integer', 'real',
        'double' and 'ascii'.  The default is determined from the format
        of the value parameter or from the type of the item if it was
        already present.  Normally you can allow this parameter to
        default.
 
        PUTHD will complain when you change the datatype, but otherwise
        allow you to do so.