real*4 lambda,dist,theta,pix,yfilm,x,d
	lambda=1.08
	write(6,*)'Enter IP Distance (mm):'
	read(5,*) dist
	write(6,*)'Enter beam center coord (in pixels):'
	write(6,*)'600 600 or 1000 1000 or 950 950'
	read(5,*)xc,yc
	write(6,*)'Enter pixel size (mm):'
	write(6,*)'0.15 for MAR, .105 for RAXIS'
	read(5,*)pix
	write(6,*)'Enter wavelength:'
	write(6,*)'1.08 for MAR,1.5418 for RAXIS'
	read(5,*)lambda
10	write(6,*)'Enter spot coord (in pixels):'
	read(5,*,end=20) xf,yf
        xf=(xf-xc)
	yf=(yf-yc)
	yfilm=pix*sqrt(xf*xf+yf*yf)
	theta=atan(yfilm/dist)/2
	d=lambda/(2*sin(theta))
	write (6,*)d
	goto 10
20	continue
	end