Sunspots

Sunspots and Limb Darkening
photo by Thom Zeman

Sunspots are aligned  parallel to the solar equator, which runs from just above the center of the left edge to just below the center of the right edge.  The photograph also shows "limb darkening," which shows as a darker edge to the sun.   Limb darkening is due to the cooler temperatures encountered higher up in the photosphere of the sun, which is the part that is seen along the edges where the view is tangential;  in the center of the view the deeper, hotter portions of the sun produce a brighter image.  The blue color is due to the aluminized Mylar solar filter that was used to reduce the intensity of the light.  The photograph was made on the 6-inch reflecting telescope.