Design of a Compact Camera Obscura

Abstract

The camera obscura is a well-known optical device in the form of a closed box with a hole in one of its walls through which light rays pass, forming an inverted image of the external objects on the opposite wall, as can be seen in Fig. 1(a). Despite the simplicity of its basic design, they have been widely used by scientists and artists. In particular, dark cameras have been used throughout history to measure Earth-Sun distance. To do this, ancient scientists used cameras of enormous dimensions to accurately measure the variations in the apparent diameter of the Sun that depend on the Earth-Sun distance. This is because the farther the light travels inside the camera, the larger the projected image will be [Fig. 1(b)]. In this work, the construction of a compact dark camera for educational purposes is presented so that, having reduced dimensions, it allows the images to be very large.