Image

Corona up to 3.5 solar radii

The raw input data used for creation of this image have 57.2 GB (1891 raw images - eclipse images, dark frames and flat-fields before RGB matrix interpolation and RGB separation). The image presented in this web page was made from data obtained by means of three different cameras with lenses from 760 mm to 1624 mm focal length (see the table below). It was necessary to combine data from all these cameras because of rolling clouds. If the sky is clear, only one camera would be enough for creation of image of this quality. But the sky during the totality was far from to be perfect. The nearest neighborhood of the Sun was clear only for several rather short intervals. Fortunately even these several dozens of second long intervals were enough because of the exposure sequence strategy which was prepared for this eventuality. The main data set consists of images taken by means of Rubinar 10/1000 mm and other two sets of images were aligned with this set using phase correlation based on Fourier transform. The alignment was necessary between different cameras only, because the tracking of the fantastic Astelco NTM 500 mount was in sub-arcsecond precision during the eclipse.
 
The stars are not round because the Sun is moving rather fast among the stars - about 1° per day. The star trails are of different length because every image part consists of different images taken at different time. The trails of bright stars are usually longer because they are recorded on more images than faint stars.
 
The full resolution image is here.
Click on the image or on the following reference to display the higher resolution image version (2.4 MB, PNG format).

ImageTse2010t_wrr1.png
Date11. 07. 2010
Time2nd contact 18:45:36 UT, 3rd contact 18:50:05 UT
Total eclipse duration 4 m 29 s
PlaceTatakoto Atoll, French Polynesia
CoordinateS 17° 20' 39.3'',   W 138° 27' 3.1'',  Alt. 6 m
ConditionsPartially clear, partially thin clouds
Optics(1) William Optics FLT 110 mm APO F/7.0 + field flattener, focal length 760 mm
(2) Rubinar 10/1000 mm
(3) GSO RC 8'', Ritchey-Chrétien F/8, 203 mm/1624 mm
Camera(1) Canon EOS 5D Mark II digital camera (ISO 100)
(2,3) Canon EOS 5D digital camera (ISO 100)
Exposure(1) 1/500 s - 8 s
(2) 1/125 s - 8 s
(3) 1/500 s - 2 s
ProcessingComposition of 120 eclipse images (26 (1), 33 (2) 61 (3)). Eclipse images calibrated by means of dark frames and flat-fields, aligned by means of phase correlation, composed by means of LDIC 5.0 software, processed using Corona 4.1 in order to visualize coronal structures. Final processing was done using ACC 6.1 software.
Image processing by Miloslav Druckmüller
SoftwareAstro D3F 2.0, PhaseCorr 6.0, MPA 1.0, LDIC 5.0, Corona 4.1, Sofo ACC 6.1
OrientationImage must be rotated 10.8° anti-clockwise to achieve standard orientation i.e. solar north up.
Copyright© 2010 Miloslav Druckmüller, Martin Dietzel, Shadia Habbal, Vojtech Rušin
 


Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
druckmuller@fme.vutbr.cz
Page last update: 1.8.2014