ASTRONOMICAL REFRACTING TELESCOPE and REFLECTING TELESCOPE

This Poweroint begins by showing how light rays travel through a convex lens. It also shows the formation of images with the object at different distances from the lens.
As an illustration of the use of a convex lens it includes showing how the camera and the magnifying glass each form an image.
It then goes on to show, step by step, how rays of light travel through an astronomical refracting telescope and shows the angle subtended by image and the angle subtended by the object.
It shows, in detail, how the angular magnification can be found. It also points out that the telescope length = the sum of the objective and eyepiece focal lengths.

The second PowerPoint shows how light rays travel through a Cassegrain reflecting telescope.

Rays are drawn in stages to show all the steps in constructing an accurate ray diagram.