The sun is the center of our planetary system. About it the planets move in regular orbits. It is one of the fixed stars. It looks much larger than the other fixed stars because of its relative nearness to us. All of our heat and all of our light come directly or indirectly from the sun. The heat that we get from wood or coal has been stored there because of the warmth and light furnished by the sun. The light of the moon is light reflected from the sun. It is small wonder then that the ancients formerly worshipped the sun as the great god of the universe. The upper part of the disk appears to be partly cut off. The dark patches that cause this are called sun spots. Two small separate sun spots will also be seen. Sun spots are believed to be somewhat like the storms in the Earth's atmosphere. The mottled or speckled effect of the surface of the sun is supposed to be due to great clouds that come from metallic gases in the sun's atmosphere. The very bright spots that show extremely white in the view near the edge of the sun's disk, are called "faculae". These are supposed by some astronomers to be elevated regions on the sun's surface. The diameter of the sun is 876,000 miles, or 110 times that of the Earth. Its mean distance from the Earth is 93,000,000 miles. At its equator it rotates on its axis in 25 days; or as seen from the Earth, in 27 days. This photograph was taken through the Yerkes telescope of the University of Chicago at Williams Bay, Wisconsin. This telescope was mounted in 1896-97 at a cost of $125,000. It has 40-inch lenses, the largest in America. The length of the tube is 65 feet. The telescope weighs nearly 15 tons. Keystone ID: 16764 Note: All titles, descriptions, and location coordinates are from the original Keystone Slide documentation as supplied by the Keystone View Company. No text has been edited or changed.