It is the white, bright surface we see with thenaked eye-the luminous, 6000 K surface that radiates most of theSun's light and heat to space. The mask most commonly seen, and the first tobe studied in detail, is the Sun's white light face: the layer inwhich sunspots are seen, and which astronomy calls the sphere oflight or photosphere. In many cases, new ways of looking have revealed new andpreviously hidden faces of the Sun, for the Sun's appearance changesdramatically from layer to layer, as though it wore mask on mask onmask. Each new look has shown the Sun to be more active and morecomplex. Each new look, from Galileo's simpletelescope to Skylab's powerful array, has brought a new and oftensurprising view of what was once thought to be a simple sphere offire.
Indeed, man's understanding of the Sun hasnever proceeded regularly, but always in surges, following newinstrumental break-throughs. Without them we would know little more of the Sun thanits position in the sky. The story of what we know of the Sun is alsothe history of solar instruments: the telescope, spectroscope, andmany others. But, if the telescope is a good one and the atmospheric conditions favorable, the details soon begin to come out. At first view, indeed, it is less impressive than the moon there is not so much to attract the immediate attention-no mountain-ranges and craters, no shadows, rills, or rays. When an observer, provided with suitable telescopic appliances, examines the surface of the sun, he finds a most interesting field before him. Theirdetails were discovered by Galileo and others who looked at them withthe first telescopes in the early 17th century Sunspots can be seen with the naked eye under favorableconditions and have been observed for thousands of years. They are darker than the surroundingphotosphere because they are cooler - about 4200 K as compared to6000 K. SUNSPOTS are revealed when the Sun isseen with an ordinary telescope.
SP-402 A New Sun: The Solar ResultsFrom Skylab
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