measure encircled energy vs radius and return as an interpolator
Returns a function object which when called returns the Encircled Energy inside a given radius, for any arbitrary desired radius smaller than the image size.
HDUlist_or_filename : string
ext : int
center : tuple of floats
>>> EE = measure_EE("someimage.fits") >>> print "The EE at 0.5 arcsec is ", EE(0.5)