White-light corona and SOHO EIT 17.1 nm image

This is a nearly realistic view of the solar corona in the visible light which could be seen if it was possible to switch off the solar photosphere radiation. The image was created from an eclipse image, in which the part hidden by the Moon was replaced by SOHO EIT 17.1 nm image (Fe IX/X). Smooth transition between both images makes the boundary between the eclipse image and SOHO EIT image nearly invisible. The photosphere (temperature 5 780 K) being compared to the corona (temperature over 1 000 000 K) is black in the wavelength of 17.1 nm and therefore a total eclipse is not necessary for a corona observing. Even if there is a big difference in wavelengths used for taking both images, there is a very high similarity in the appearance of the corona on these images. The resulting image gives much better 3D imagination of coronal structures than an eclipse image only.
Click on the image or on the following reference to display the higher resolution image version (2.8 MB, PNG format).

Date29. 03. 2006
Time2nd contact 10:35:39 UT, 3rd contact 10:39:38 UT
SOHO image 11:00:14 UT
Coordinate30° 56.946' N, 24° 14.301' E, 158 m altitude
ConditionsExcellent - clear sky, altitude of the Sun above the horizon 62°
Optics16.4/1640mm (Takahashi 100 mm ED, focal length 820 mm with Canon 2× teleconverter)
CameraCanon EOS 5D digital camera (ISO 100)
Exposure1/1000 s - 4 s
ProcessingComposition of 60 eclipse images and SOHO EIT Fe IX/X 17.1 nm image. Eclipse images were alignment by means of phase correlation, composed by means of LDIC 4.0 software, processed using Corona 4.0 in order to visualize coronal structures. Final processing including alignment with SOHO image was done using ACC 6.0 software.
Image processing by Miloslav Druckmüller
SoftwarePhaseCorr 4.0, Corona_ret 2.0, LDIC 4.0, Corona 4.0, Sofo ACC 6.0 with Match II module
OrientationImage must be rotated 24.258° anti-clockwise to achieve standard orientation i. e. North up.
Copyright© 2006 Miloslav Druckmüller, Peter Aniol, ESA/NASA

Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
Page last update: 24.8.2008