How the Hubble Telescope operates.
The Hubble Telescope works in a very similar manner to that of our eye. The light comes in an opening in the telescope (The Cornea) which bends the light. The light is then reflected roughly of a concave Primary Mirror and onto the Secondary convex mirror ( The Lens). This mirror then reflects the light onto a focal point where it is recorded by instruments inside the telescope (The retina) where the light is processed and is then formed into a picture. The image is then converted and sent to a computer server on earth ( The Optic Nerve).
A concave or converging mirror is a mirror which has a reflecting surface that bulges inward. Concave mirrors reflect light inwards to one focal point. The mirror is known as converging as they tend to collect light that shines into them and refocus parallel incoming rays towards a focal point. Which in the case of the telescope is the secondary mirror. The secondary mirror is a convex mirror which takes the light shined on it and reflects it into one exact point. This point is located within the scientific instruments which take the raw light and convert it into a visible picture which is then sent to Earth. The entire telescope relies upon scientific understanding of how light bends under different circumstances. If the mirrors where to be rounded at a angle even one degree different the telescope wouldn't function.