Sunday, April 4, 2010

As the Sun turns...

I had the unusual opportunity to observe the Sun three consecutive days this weekend - Friday, Saturday and Sunday.  I thought that it would be neat to put my three sketches here in sequence so that one can get an idea of the speed with which the Sun rotates.  It takes approximately 24.5 days for the sun to rotate at the equator.  Therefore, if a feature persists long enough, it can be observed for about 12 days as it slowly makes its way across the face of the Sun.

Keep in mind that my drawings are more art than science and the locations that I place details are eyeballed ~ that is to say I look in the eyepiece and plot them on my sketch without determining the precise position on the solar disc.  I determine north and west by moving the mount.

Thomas Ashcraft, a skilled solar observer in New Mexico took pictures of the Sun very close to the same times that I made sketches.  Thomas and his work were recently featured on National Public Radio's All Things Considered.  I highly recommend listening to his interview.  His photos are underneath my sketches as the locations of solar features in his images are, obviously, accurate! 

You will notice that the images are reversed left to right from my sketches.  You can compare Thomas' images to my sketches and see that I am close on the locations.   The Sun rotates from east to west and you can see the active regions and filaments moving closer to the west limb each day.  Left to right, the photos are from April 2nd, 3rd, and 4th:


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