def ellipse(im, i_deg, phi_deg):
    Ys = im[0]
    Xs = im[1]
    # x,y are points in the sky plane that we transform to the ring plane
    # ellipse projection will occur automatically
    (x11, y11, ellipser) = sky_to_ring(Xs, Ys, 90.-i_deg, phi_deg)

    return ellipser
make an ellipse in an input array
dataset/ETHPy150Open mkenworthy/exorings/exorings.py/ellipse