def ellipse_strip(r, tau, y, hjd_central, i, phi, star, width):
    xrang = 200.
    yrang = width

    star_x, star_y = np.shape(star)

    ny = star_y
    # calculate the effective pixel width for mgrid in days
    dt = yrang / (ny - 1)

    nx = np.floor(xrang/dt)

    yc = (ny - 1) / 2.
    xc = (nx - 1) / 2.

    agr = np.mgrid[:ny, :nx]

    agr[0] -= yc
    agr[1] -= xc
    agr = agr * dt

    # move up to the strip
    agr[0] += y

    tau_disk, grad = ellipse_nest(agr, i, phi, r, tau)

    tau_disk_convolved = convolve(tau_disk, star, mode='constant', cval=0.0)

    # pick out central rows from convolution and the actual xvals
    x_tdc = agr[1, yc, :] + hjd_central
    tdc = tau_disk_convolved[yc, :]
    td = tau_disk[yc, :]
    g = grad[yc, :]

    return(tau_disk, tau_disk_convolved, np.vstack((x_tdc, tdc, td, g)))
calculate a strip of values suitable for star convolution
dataset/ETHPy150Open mkenworthy/exorings/exorings.py/ellipse_strip