The image shows two diagrams, one labeled "Cassegrain" and the other labeled "Gregorian". The diagram on the left shows a convex secondary reflector, which is a type of reflector that is used to reflect the surface of a material. The converse secondary reflectors are shown in red and blue colors, while the Gregorian reflectors in green and blue are shown on the right. The image also has text written on it that explains the different types of reflectors and their properties.
User macever uploaded the image
User macever uploaded the image
