Antisolar point anthelic point, such as the anthelion, Wegener arcs, Tricker arcs and the parhelic circle itself. Antisolar point The antisolar point is the abstract point on the celestial sphere directly opposite of the Sun from an observer's perspective. This means that the antisolar point lies above the horizon when the Sun is below it, and vice versa. On a sunny day, the antisolar point can be easily found; it is located within the shadow of the observer's head. Like the zenith and nadir, the antisolar point is not fixed in three-dimensional space, but is defined relative to the observer. Each observer
Overhead projector optics that eliminate the "hotspot" in the center of the screen directly above the light source, so that the brightness is uniform everywhere on the projection screen. Critics feel that there are some downsides as these technologies are more prone to failure and have a much steeper learning curve for the user than a standard overhead projector. Overhead projector An overhead projector is a variant of slide projector that is used to display images to an audience. The name is often abbreviated to OHP. An overhead projector works on the same principle as a 35mm slide projector, in which a