Sunday, September 25, 2005
The Sun is "on fire"
On Wednesday the 21st of September the Sun was on fire. It is hard to explain in words what I saw. Early in the morning I pointed the Coronado PST at the Sun. Large parts of the solar limb seemed to be alive with large prominences, and on the solar disk I could detect a large active region, AR 0810 and a few filaments. AR 0810 was visible as a sunspot (dark, black), with a large bright area (plage). There was also a large filament between the active region and the limb of the Sun. The most spectacular features where the large prominences. One of them was completely detached from the Sun and seemed the hover in space.

It is amazing what you can see with the PST. I shot the image below later that day. It should give you an idea of what I saw, but I have to admit that the image doesn't come near to what I actually saw through the small solar scope. The filaments looked like very fine threads and I cannot capture them as I visually saw them. But that goes for a lot of objects. I once observed M 13 under very good conditions with a superb telescope. There is no single picture that comes even near to what I saw that night. Any camera cannot beat the eye-brain combination. I'm sure of that.

Anyway, here's the best image I could shoot (and process) of this "flying" prominence. It was shot with the Nikon Coolpix 4500, image size 2272 x 1704, highest quality, iso 100, 1/8 second, f / 8.2. I used a 15mm Vixen Lanthanum eyepiece (magnification is about 26x) and 4x optical zoom. Image processing: level adjustment (in different color channels), brightness/contrast, hue/saturation (only in magenta) and unsharp masking.


What I also learned that day, is that there are probably two factors that are very important for getting good images: get the image focussed as good as possible and shoot a few series, so you can catch a moment of good seeing. I shot a few series in the morning, and I didn't get one good image. Around 12 O'clock local time I shot another series, with the same equipment and settings. I got significantly better images than a few hours before. Only two things could have changed: I re-focussed the camera and probably got lucky with moments of good seeing.

Enjoy cool smile
Posted by Math on 09/25 at 05:35 AM | (0) Comments | filed in: Solar log | Print