C+
C NAME:
C	AIPS_WTF
C PURPOSE:
C	freq=IPS Observation Frequency
C	1=327.0MHz: STELab. Nagoya Univ; 2=81.5MHZ: Cambridge Univ.; 3=73.8MHZ: UCSD
C CALLING SEQUENCE:
	function AIPS_WTF(im,zdist) ! Calculate IPS weighting function along los
C INCLUDE:
	include		'sun.h'
	include		'phys.h'
	include		'math.h'
C EXTERNAL TYPE:
	real		IPSFuncQ
C EXTERNAL:
	external	IPSFuncQ		! Spectral function
C COMMON BLOCKS:
	common	/FQIPS/	hachodz,thetadz
!$omp threadprivate(/FQIPS/)
C CALLS:
C	Simpson
C PROCEDURE:
C-
	    integer	im
	    real	zdist

	real	freqs (3)	/327.0,81.5,73.8/! Freq. (MHz)
	real	thetas(3)	/  0.1, 0.3, 0.3/! Source size (arcsec)

	hacho = 0.1*PHYS__c/freqs(im)	! Radio wavelength (km)
	theta = thetas(im)*MATH__RPD/3600! theta=Source Size(arcsec->radians)
	dz  = zdist*SUN__AU*1.e+8	! Dist along los (AU->km)

	thetadz = theta*dz
	hachodz = hacho*dz

	W = 0
	if (thetadz .ne. 0) W = Simpson(IPSFuncQ,0.0,sqrt(60.0)/thetadz,1.0E-5,13,N)

	AIPS_WTF = W

	return
	end