The solar viewing sessions allow for safe telescopic observation of the sun using special solar filters to view sunspots. (Never look at the sun with the naked eye.)
Sunspots are cooler regions of the solar surface caused by intense localized magnetic fields that bring the upward convection of internal material to a virtual standstill. Although they appear almost black, this is merely a contrast effect. If it were possible to place a modest-size sunspot into the night sky, it would shine 10 times brighter than the full Moon!
Even the casual observer will soon learn that sunspots come in a wide variety of shapes and sizes. While the simplest sunspots are isolated dark areas, larger spots are quite dramatic. Complex spots feature a dark central region called the umbra surrounded by a gray penumbra. The penumbra normally appears as a smooth fringe, but under steady seeing conditions it may exhibit radial patterns or knots of light and dark