The above photo of the sun was taken today, 12 August 2008. A DSLR camera was used at the prime focus of a 102mm (700mm focal length) Schmidt-Cassegrain telescope. A full-aperture, white-light solar filter covered the front of the telescope.
I knew the sun was without spots today - as it has been for quite some time now. Nevertheless, even a spotless sun can be of interest. Notice that the limb (edge) of the sun is darker than the center of the sun. This is called "limb darkening" and is due to much of the solar radiation originating deep within the interior (rather than the 'surface') of the sun.
The sun goes through a roughly 11-year sunspot cycle. Approximately 11 years pass between sunspot maximums. Sunspot minimums occur roughly midway between the maximums.
No comments:
Post a Comment