Project     : SDAC
                   
 Name        : WASK
               
 Purpose     : This procedure generates a dialog response widget.
               
 Category    : WIDGET
               
 Explanation : 
 wask brings up a widget that asks a question that can be answered
 with a yes or no.  Caller supplies question in a string argument.
 answer = 0/1 meaning no/yes is returned.

               
 Use         :   wask, answer=a_answer [, question=question, group_leader=group ]                


 Examples    :
	 wask, quest='  Define new background intervals?  ', $
                  answer=getnewback, group_leader=base

    
 Inputs      : 
               
 Opt. Inputs : None
               
 Outputs     : None

 Opt. Outputs: None
               
 Keywords    : ANSWER (output)- 1 for yes button and 0 for no.
		QUESTION (input)- Question for response.  Becomes Widget Title.
		GROUP_LEADER - widget group leader.
 Calls	      : ***
	WASK_EVENT, XMANAGER
 Common      : None
               
 Restrictions: 
               
 Side effects: None.
               
 Prev. Hist  :

 Modified    : 
 AKT 11/92

 Checks whether a window has been created (window_in variable exists)
 and if so, sets the active window to that index.  If not, creates a window
 with an unused index and returns that index in window_in.
 Keywords are the same as those used in IDL call to WINDOW.

 Kim Tolbert   5/1/92
 CALLS:
 CALLED BY
	HXRBS

 NAME:
	WLFCS
 PURPOSE:
	Calculate FCS wavelength given drive B address.
	Refractive index corrections are applied.

 CALLING SEQUENCE:
	WAVE = WLFCS(CHAN,ADDRSS)
	WAVE = WLFCS(CHAN,ADDRSS,TEMPXL)

 INPUTS:
	CHAN   = FCS channel number (1 to 7)
	ADDRSS = Vector or scalar containing FCS addresses.

 OPTIONAL INPUT PARAMETERS:
	TEMPXL = Temperature of crystal in C. If not supplied,
		 a default value of 20 (temp0) is used.

 OUTPUTS:
	FCS wavelength in Angstroms is returned as a FLT array.

 CALLED BY:
	LAMDAD, RDFIS_SPEC, fcs_par, fluxcon, plotfda
 COMMON BLOCKS:
	Common block LAT_SPACE consists of one float variable which
	contains the value of the 2d spacing of the most recently
	requested channel and crystal temperature.

 SIDE EFFECTS:
	If an invalid channel is requested, (ie., not between 1 and 7),
	WLFCS will issue a message and return undefined value.

 RESTRICTIONS:
	CHAN	must be a scalar.
	ADDRSS 	may be a scalar or array of integer,byte, or real type.

 PROCEDURE:
	The wavelength is calculated from the expression:

		wavelength = 2d*sin(theta) * (1.0-DEL/(sin(angle)^2)))

	where DEL describes the refractive index correction.  The
	value of DEL has been approximated for the 7 FCS channels
	by a 4'th order polynomial fit made by B.K. Kent.
	
	
 MODIFICATION HISTORY:
	This routine is a modification of B.K. Kent's FORTRAN program FCSLST.

	Sep, 1985,	Written, J.R. Lemen, MSSL