Improved outer corona image

The image of outer corona which was presented on the previous page cannot be enlarged too much because there is not enough contrast on high spatial frequencies in outer part of corona i.e. the outer part of corona is not sharp enough being compared with the inner part. The reason for it is that the image was created from images taken by two instruments with significantly different focal lengths (200mm and 1084mm). In the end I found solution how to improve the sharpness in outer part of corona. I used SOHO C2 image taken at 10:28:07 UT. The image itself cannot be directly used because the inner part of corona is missing and the image has a lot of artefacts caused by light diffraction which I was not able to remove correctly. Therefore I used only the high spatial frequencies and only from the most distant part of corona for improving the above mentioned image sharpens.
Click on the following reference to display the same image in the maximum quality (729 KB, PNG format).

Date11. 08. 1999
TimeSecond contact 10:50:37 UT, third contact 10:53:00 UT
Total eclipse duration 2 min 23 s
PlaceHungary, 2 km SSE from Németkér village
CoordinateN 46° 41' 36'', E 18° 47' 14''
ConditionsExcellent, clear sky. (Solar altitude 59° above horizon)
OpticsMaksutov - Cassegrain MTO 1000a, 10.5/1084mm and Sonnar 2.8/200mm
Resolution16.8 arc sec / pixel (image on this Web page)
FilmFujicolor Superia 800 (for MTO), Agfacolor HDC 400 Plus (for Sonnar)
ProcessingAdaptive processed composition of 28 images (6 taken with Sonnar, 21 taken with MTO, 1 SOHO C2)
Image processing by Miloslav Druckmüller
ScannerNikon Super Coolscan 4000 ED (4000dpi resolution, 16× multisample)
SoftwareSofo ACC 6.0, Corona 3.0, PhaseCorr 3.0
OrientationThe image has the standard orientation i.e. North top, East left
More infoComplete set of processed images and animation including many texts about Sun and solar eclipses was published on multimedia CD: Miloslav Druckmüller, Journey to Solar Eclipse, AION and WOLF RECORDS, 2000
Copyright© 2004 Hana Druckmüllerová and Miloslav Druckmüller


Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
Page last update: 19.3.2007