👉 In physics, a heliograph is a device used to produce a visual image of an object from its reflection in a liquid or gas. The term "heliograph" comes from the Latin word "heli," which means sky, and "graphus," which means image. A heliograph consists of a mirror (the reflecting surface) placed on top of a prism that is used to cause the liquid or gas to vibrate in response to an electric current. This vibration causes the
