Why is my image upside down?

Another video in our series dealing with the basic principles of astronomy telescopes. This presentation explains why the image viewed in a telescope designed for astronomical viewing, as opposed to terrestrial, always presents the eye with an image that is not rectified (ie, looks upside down or flipped left to right). Presented by Robert J Dalby FRAS for The Astronomy and Nature Centre Produced by DB Video Services for Astronomy and Nature TV