Filament Triple

Features Bloom

Only five days after my last solar observing session the sky was clear again. On September 27th there were lots of nice features facing Earth. Gentle breezes and mild temperature in the 70's made afternoon observing pleasant. Seeing conditions were not particularly good, however.

Since so many solar features had bloomed, I decided to make a mosaic of the entire Sun, including prominences and spicules on the limb. For more than an hour I recorded images with a 2X Barlow lens. The first image set captured the relatively bright disc. The second image set captured the relatively dim limb. The following mosaic is a combination of 41 individual images: 22 for the disc, and 19 for the limb. In spite of processing and combining the images for several hours the final result is imperfect. Some individual images were blurrier than average, and there was too much overall brightness difference among individual disc images. The result is slight unnatural brightness variation over the disc and subtle horizontal or vertical boundaries between dark and light regions. The imperfections lessen somewhat when the mosaic is viewed at full size, so: (Click on the image for a larger view.)

Three enormous dark filaments stretch out near center and the upper right. The two nearest center were magnificent prominences a week earlier on the left limb. Sunspots dot the right half of the Sun. A few prominences are scattered around the limb. The three biggest filaments stand out nicely in the following inverted version of the previous image.

The first two mosaics were made by stacking the best 40 frames from individual 400-frame videos. The next image was constructed by stacking the best 100 frames from individual 1,000-frame videos. This picture is cropped from a 21-image mosaic and shows most of the sunspots and the three major dark filaments. At top right is sunspot 2175 next to a curved filament. Below center, stretching diagonally upward from left to right, are sunspots 2172, 2173, and 2171.

The inverted version follows.

Next is a close view of sunspots 2172, 2173 and 2171 stretching diagonally across the picture. The detail here is fairly good in spite of the mediocre seeing. This is a wonderfully complex sunspot grouping!

I still haven't managed to create a flawless mosaic of the entire Sun, but I'm getting closer.