Leonardo da Vinci designed and described a camera obscura for projecting an image of the Sun during an eclipse. A camera obscura is a dark chamber or box in which light passes through a small opening and forms an image on an opposite surface.
Leonardo studied the device extensively in his notebooks during the late fifteenth and early sixteenth centuries. He used it as a model for understanding how light travels and how the eye may receive an image. His observations included the fact that the projected image appears inverted.
Leonardo did not invent the camera obscura. The basic principle was known in antiquity, and earlier scholars had described solar images formed through small openings. His importance lies in detailed investigation and application of the device to optics and vision. A camera obscura is also not a telescope: it projects an image but does not use lenses to magnify distant objects.