Definition
A reseau (pronounced reh-zoh) is a grid or network of fine lines or markings placed in the focal plane of an optical instrument, like a camera or telescope. 🔭 It serves as a reference for measurements and to correct distortions in images. Imagine a subtle grid overlay on a photograph. Reseaus are commonly used in astronomy and photogrammetry. They ensure accuracy in scientific imaging. The term implies precision and calibration.