May 3, 2008: High Resolution Limb Movie

This is a 15MB Flash-format time lapse movie of the Solar limb on May 3rd, 2008, captured and processed by Fred Bruenjes. Comprising 190 frames taken at 30 second intervals over 1.6 hours, it shows prominences, dancing spicules, and granulation. Average seeing. 6" F/8 refractor, 4x Powermate, DayStar 0.45Å H-alpha Quantum PE filter, 0.63x focal reducer, Moonglow Technologies interference eliminator and prototype gigabit ethernet camera. Cropped and reduced to 50% of original size.

Image processing steps:

1. Using the optical configuration described above, every 30 seconds a burst of 100 frames was saved to disk in raw format at full 12bit, 2056x2062 resolution. Total disk space used was about 120GB.
2. Custom software was then used to select the sharpest frame in each 100 frame burst, using a gradient method. No stacking, multiple exposures, or masking was used.
3. Maxim DL was used to flat field each of the selected frames in order to remove dust spots, etc. Some dust particles were too big and could not be corrected, they can be seen as dots that dance around randomly.
4. Custom software was used to align each image, using 2048 point FFTs. Two frames had seeing poor enough that they had to be tweaked by hand for fine alignment.
5. Photoshop was used in batch mode to adjust levels, colorize, resize to 50%, and sharpen each frame.
6. The frames were cropped to 800x600 and finally assembled into a Flash file using ffmpeg. Due to the color encoding scheme used by Flash, significant resolution was lost in the chromosphere and prominences.