Sunday, October 19, 2014

Sun's up

Another grand sunspot is rotating into view:

The photo was taken today (19 Oct. 2014) with a white-light solar filter over an 8-inch Schmidt-Cassigrain telescope at F10. I added a little yellow tone for aesthetics.

The photo below shows the sun with my scope's focal ratio reduced to F6.3, allowing me to get the full sun on the frame. The inset highlights the sunspot.

This sunspot will rotating toward the middle of the sun (from our viewpoint). It is the type of sunspot that will make news if it lets loose a flare while pointing at us. On the other hand, it may fade slowly and uneventfully.

Below, I've doubled what one can do with a solar filter. It's great for solar selfies. Here's me, my camera, and our sun in the solar filter, which is essentially a mirror that reflects 99.9% of light.

I pulled out just the sun from the above photo. The photo was taken at 39 mm focal length. I believe a camera at 50 mm focal length produces images of a scale matching human perception. So, the sun in this photo should be smaller than human perception. With that in mind, I wondered if this sunspot would be visible to the naked eye under cloudy or hazy conditions that allowed for a safe glimpse. DO NOT LOOK AT THE SUN, but I suspect this one under special natural conditions could be viewed with naked eye. You can see a fragment of the grand sunspot in the lower left corner:


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