pääsäteen
Pääsäteen is a Finnish term that translates to "main ray" or "primary ray." It is primarily used in the context of optics and geometry, referring to the principal line of light or a fundamental directional vector. In optical systems, the pääsäteen often denotes the path of light that passes through the center of an optical element, such as a lens or mirror, without undergoing refraction or reflection. This ray is crucial for defining the optical axis and understanding the behavior of light within the system.
The concept of pääsäteen is also relevant in ray tracing, a computational technique used to simulate the