Middle Corona Structure - SOHO LASCO C2 Composite

This image shows the corona structure up to six solar radii. It is impossible to obtain an image of such quality neither from ground based eclipse observations nor from SOHO LASCO C2 coronograph. Ground based observations are influenced by the Earth's atmosphere and the contrast of coronal structures in distance of six solar radii is so low that it cannot be significantly improved even by sophisticated mathematical methods. On the other hand SOHO coronograph has its "blind area" near the Sun up to 1.5 radii. This area is highly influenced by diffraction on "artificial Moon". The combination of ground based eclipse image with SOHO C2 coronograph image gives a unique opportunity to create high quality image of middle corona.
Click on the image or on the following reference to display the higher resolution image version (1.1 MB, PNG format).

Date 21. 06. 2001
TimeSecond contact 12:36:34 UT, third contact 12:41:10 UT
Total eclipse duration 4 min 36 s
PlaceAngola, near Sumbe (Ngunza)
CoordinateS 11° 07' 29'', E 13° 55' 51'', Alt. 168 m
ConditionsExcellent, clear sky
OpticsMertz - II, 1875/100 mm (VOD Turnov), siderostat off-axis configuration
CameraPENTAX 67 II, 6 × 7.5 cm format
Resolution11.9 arc sec / pixel - full resolution image version
FilmKodak Ektachrome 100 S Professional
ProcessingSum of 8 images enhanced by means of adaptive kernel convolution (color image) composed with SOHO LASCO C2 image taken at 12:34:14 UT.
Image processing by Miloslav Druckmüller
ScannerNikon LS 8000 (4000dpi resolution, RGB, 3 × 16 bit/pixel)
SoftwareSofo ACC 5.0 Scientific Image Analyzer with Match II Module (final processing)
Corona 2.0 Analyzer (coronal structure enhancement)
PhaseCorr 2.0 Analyzer (rotation estimation - registration of images)
NoteSOHO LASCO C2 image file name 2096643.fts
OrientationImage has standard orientation (N top, E left)
Copyright© 2001 Úpice Observatory, © 2001 ESA/NASA, © 2003 Miloslav Druckmüller


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