Figure 29. Beams coming out of the focus of the parabola and reflecting parallel to the focal axis

From

The Experimental Teaching of the Conics Using the Reflection of the Light: The Conceptual Study of the Cassegrain Telescope

Juan Carlos Ruiz Mendoza

American Journal of Educational Research. 2019, 7(10), 699-707 doi:10.12691/education-7-10-5