The (almost) Unblemished Sun

June 23, 2020  •  Leave a Comment

The Sun is a very powerful nuclear energy generator. Fortunately it produces a very constant, copious flow of energy that pours from the Sun's surface as bright, white light. But if you can look in greater detail, the visible surface of the Sun is a very dynamic place that changes on different time scales from seconds to days to decades. Eventually it will run out of hydrogen for its primary nuclear fuel and things will get very dramatically different, and not so good for life here on Earth. But don't worry, that's not for billions of years. 

Some of that activity is visible as sunspots, darker areas that are cooler than the surrounding visible layer due to complex magnetic activity. Sometimes powerful flares erupt from the surface that blast vast quantities of energy and particles, some of which can reach the Earth and beyond. The most powerful ones can disable orbiting satellites and knock out power grids. We can also see prominences at the limb, fingers and arches of glowing hydrogen plasma sculpted by magnetic forces. Normally we need specialized equipment to view these but during rare total solar eclipses we can see them with naked eyes through small telescopes because the Moon blocks out the brightest part of the Sun. I was able to photograph prominences during the eclipse of 2017. 

The Sun is going through a deep sunspot minimum now though, meaning the overall activity of the sun is low and there are very few if any sunspots visible these days. One sunspot did appear recently though and I was able to photograph it each day it as it moved across the face for about a week. The same sunspot appears on consecutive days as dark dots below the center, superimposed onto a single image. Unfortunately I missed the first couple of days after it appeared, otherwise there would have been another spot on the left side of the sequence. They are not spaced equally because I didn't take them all at the same time of day. The sunspot is actually relatively stationary on the Sun's visible surface, but the whole Sun rotates with a period of about 25 days. Actually since the Sun is entirely gas and plasma, different parts rotate at different speeds, unlike a solid body like the Earth. If there were several spots at different latitudes we would see them move across the Sun at different speeds. 

Tech: Nikon Z 6, Celestron C5 telescope (1250mm f/10), eight frames, 1/2000 sec, ISO 100. iOptron CEM25P mount, Baader solar filter. Post-processed in Adobe Lightroom and Photoshop.


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