👉 A helicograph is a type of optical instrument used to measure the angle of incidence of light. It is also known as a Helical Refraction Meter or Helical Angle Measuring Device. The basic principle behind the helicograph is that light rays are refracted when they pass through an object, creating a helix-like shape in the beam. This effect is exploited by measuring this helix's length, which can be used to determine the angle of incidence of light at different points on
