It’s not possible to capture the full dynamic range of the solar corona in one single exposure. The solution to this limitation is to take several exposures of different lengths and then afterwards combine those to get one image that covers the whole dynamic range. However, aligning the images is not a simple task! You cannot use the Moon as reference, as this will have moved between each exposure, and the corona itself seldom have distinct features suitable for using as a reference. Combining the images in a way that makes the corona look natural is another challenge. Prof. Druckmüller has developed a set of highly specialized programs to overcome these obstacles. Using his mathematical skills he has found solutions for registering the images with very high precision, combining them preserving the full dynamic and finally applying filters to extract the details hidden in the image. The final results from this process are truly stunning!

After the speak I approached Prof. Druckmüller to hear if he would be interested getting access to my images of the December 4th 2002 eclipse images taken from Australia. I think at first he was a bit skeptical when heard that the images where obtained through a small refractor with only 60mm diameter and with the Sun only 6° above the horizon, but he agreed to give it a try. 

Working with images from a DSLR was somewhat different than working with scanned film images and some adjustments where needed to the software, which delayed the processing of my images. In September 2005, however, I finally received an email from 
Prof. Druckmüller containing the resulting image. He noted in his email that despite the small aperture and low altitude of the Sun, he had found the quality of the images surprisingly high. The atmospheric refraction distorted (flattened) the images and gave the corona a golden hue, but the resulting image still have a great level of details in the corona. Image must be rotated 77.8° counterclockwise to achieve the standard orientation (N top, E left)

Compared to images taken about 3 hours earlier from Africa by Vojtech Rušin and Friedhelm Dorst (also processed by Prof. Druckmüller) the corona has changed quite a bit.


I’m very grateful to Prof. Druckmüller for allowing me to participate in his MMV project and for taking the time to process my images. A visit to his homepage to look at more of his stunning work is highly recommended!