def METHOD_NAME(t, theta0, phi0):
    """ 
    Calculates the point on a great circle defined my theta0 and phi0 in Cartesian coordinates. 
    Sources:
        - http://demonstrations.wolfram.com/ParametricEquationOfACircleIn3D/
    Arguments:
        t: [float or 1D ndarray] phase angle of the point in the great circle
        theta0: [float] Inclination of the great circle (radians).
        phi0: [float] Nodal angle of the great circle (radians).
    Return:
        [tuple or 2D ndarray] a tuple of (X, Y, Z) coordinates in 3D space (becomes a 2D ndarray if the input
            parameter t is also a ndarray)
    """
    # Calculate individual cartesian components of the great circle points
    x = -np.cos(t)*np.sin(phi0) + np.sin(t)*np.cos(theta0)*np.cos(phi0)
    y =  np.cos(t)*np.cos(phi0) + np.sin(t)*np.cos(theta0)*np.sin(phi0)
    z =  np.sin(t)*np.sin(theta0)
    return x, y, z