% @(#)precesopto.hlq	17.1.1.1 (ESO-IPG) 01/25/02 17:54:57
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT   (c) 1991 European Southern Observatory
%.IDENT       precess.hlq
%.AUTHOR      A. Gemmo       Padova Department of Astronomy
%.KEYWORDS    MIDAS, help files, PRECESS/OPTOPUS
%.PURPOSE     On-line help file for the command: PRECESS/OPTOPUS
%.VERSION     1.0 10-SEP-1991 : Creation, AG
%------------------------------------------------------------------------
\se
SECTION./OPTO
\es\co
PRECESS/OPTOPUS                                   10-SEP-1991 AG
\oc\su
PRECESS/OPTOPUS [inp_tab] [new_equinox]
p	recess RA and DEC coordinates in table created by CREATE/OPTO.
\us\pu
Purpose:     
             Precess RA and DEC coordinates in table created by
             CREATE/OPTOPUS command to [new_equinox]. Precessed
	     coordinates are put in columns :RA and :DEC, while
	     the old ones are respectively in :OLDRA and :OLDDEC.
             Epoch of coordinates is updated in input table 
	     descriptors.
\up\sy
Syntax:      
             PRECESS/OPTOPUS [inp_tab] [new_equinox]
\ys\pa 
	     [inp_tab]    = table created by CREATE/OPTOPUS command.
			    Default name is "opto1.tbl".
\ap\pa 
	     [new_equi]   = New epoch of RA and DEC coordinates after
			    precession. Descriptor TABEQUI (see CREATE/
			    OPTOPUS command) is updated. Default is
			    2000.0 or epoch calculated from year,month,
			    day of the observation if these data have 
			    already been set by the SET/OPTO DATE=...
			    command (see description).
\ap\no
Note:        
             [new_equi] must be given in the fomat YEAR.yyyyy so, before
	     using this command it is convenient to set the date of the
	     observation by the SET/OPTOPUS command and then to use the
	     SHOW/OPTOPUS command to make sure all the parameters have
	     been correctly set: a value of the epoch corresponding to
	     date of the observation will be automatically displayed.
\on\exs
Examples:
\ex
	     PRECESS/OPTOPUS 
\xe\ex
	     PRECESS/OPTOPUS myoptotab
\xe\ex
	     PRECESS/OPTOPUS myoptotab 1991.76776
\xe\ex
	     PRECESS/OPTOPUS ? 1991.76776876345
\xe\sxe