Local solar noon is when the sun is due south of a particular location. During winter the sun is always in the southern portion of the sky as it makes its journey east to west every day. While the sun rises and sets at different times each day (depending on the date, the location and daylight savings time) the sun is due south of that particular location at exactly half way between sunrise and sunset each day. This is useful in that the shadow of objects that are perfectly straight and vertical (tool handles, a weight hanging on a string, etc.) points due north at local solar noon and can help you properly orient your SunCatcher.