Sunday 5 June 2011

The Sun

Finally I had all the things come together at the right time (well nearly), the right place, the right weather, etc. to use our Solarscope. The Coronado Solar Max was put on an EQ mount on the observatory annexe's flat roof on Friday evening and I set up as the sun was sinking behind some cirrus clouds. Having achieved such a good North West horizon me and the tripod were very visible and got a toot from a passing car. I grabbed a sequence of shots after many test shots and adjustments (position, ISO, focus, exposure), just as the sun emerged from the bottom of the cloud at 19:30 UT (20:30 BST). After initially thinking that even they were overexposed, I found that it was just the custom white balance settings had made it look that way, and the raw files were fine. However, there is still a gradient across the disk of the sun. I think its because we have such a narrow-band H-alpha filter. The granulation and structure on the sun is AMAZING! And you may also notice that it's flattened by atmospheric refraction. I know there are better pics out there but I'm well impressed - this is my first serious attempt.

Processingwise, I input the 11 x 0.04s Canon(modded) raw 10Mpixel files in Registax and they stacked very slowly - it's the only program that worked. I sharpened up the monochome output. I added a yellow colourize, rotated and flipped to correct for the diagonal mirror. Then I masked out the bright disk and turned the atmosphere a beautiful shade of hydrogen red!

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