Documentation 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 argument can be given to
   cause conversion of the value before the item is written. Possible
   values for the units are "time", "arcmin", "arcsec", "hours", "hms"
   and "dms". Times are given in the standard Miriad form and are
   converted to Julian dates. An angular unit causes conversion to
   radians.

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.