subroutine fixell(p,r,npts,a,rfit)
      parameter (maxp=8)
      real r(maxp),p(maxp),rfit(maxp)
      real a(5)
c--centx=a1,centy=a2,position angle=a3,major axis=a4,minor axis=a5
      common /data/x,y,sigmax,sigmay
      real x(maxp),y(maxp),sigmax(maxp),sigmay(maxp)
      do i=1,npts
       dx=x(i)-a(1)
       dy=y(i)-a(2)
       r(i)=sqrt(dx**2+dy**2)
       p(i)=atan2(dy,dx)-a(3)
       esqr=1.-a(5)*a(5)/(a(4)*a(4))
       rfit(i)=sqrt(a(5)*a(5)/(1.-esqr*cos(p(i))*cos(p(i))))
      enddo
      return
      end