Image

Praesepe, Mercury, Moon, Comet, CME and Corona up to 20 solar radii

When I finished the wide-angle image of the 2006 eclipse which I made from data taken in Libya, I was sure that I have no chance to surpass this image at least until the 2009 eclipse. The observing conditions in the Libyan desert were excellent during the 2006 eclipse and the altitude of the Sun above the horizon was 62°. On the contrary, the weather prospects for the 2008 eclipse were far from to be perfect and above all, the Sun was very low - only 22° above the horizon in the Mongolian desert. Another negative factor was the length of the total eclipse - only 2 minutes. That is why the image presented on this page is highly over my wildest dreams.
 
The observing conditions in Mongolia were in reality absolutely perfect. I used data from two different cameras for the image creation. The first one was a modified Canon EOS 5D (Hutech Ia) with 200 mm lens. Mainly long exposures were taken with this camera. Taking of short exposures would be only a waste of precious time because the inner corona was recorded in high quality by means of other narrower angle lenses. Finally I used images taken with 500 mm lens for the inner corona visualization. The precise data calibration was decisive for visualization of the extremely faint outermost corona. 55 eclipse images were calibrated by means about 620 dark frames and flat-field images. This image is unique because this is the only one image in whole in MMV project archive which was made from images which were not aligned. It was not necessary, because the tracking of the parallactic mount was in subpixel tolerance during the whole total eclipse. I knew this because I had aligned images taken with longer focal lengths at first. This perfect tracking is the result of excellent work of my friend Peter Aniol, who brought his well-tried massive parallactic mount to eclipse site. The same mount was used in Libya in 2006.
 
The position and orientation of the image in the sky is shown in this map. The map was made of actual eclipse images and a star map created by means of the Sky Charts software. You may see the detailed map here. It is possible to identify at least 456 stars in the original full resolution image. The open cluster M 44 Praesepe (NGC 2632) dominates the star field. The bright object in the left part of the image is Mercury.
 
Comet C/2008 O1 (SOHO) is another interesting object which is visible in the image. This object belongs to the Kreutz family of sungrazing comets (Kreutz group I). These comets are believed to be fragments of one huge comet that broke up several centuries ago. Several members of this family have become extremely bright and were visible near the Sun during the daytime. One of the most spectacular members of the Kreutz family was the Ikeya-Seki comet visible in 1965, which may have been one of the brightest comets in the last millennium. Another member of the Kreutz family highly surprised all observers of the total solar eclipse in 1882 because before the eclipse the comet remained undiscovered. Nowadays many hundreds of small members of this family are known thanks to the SOHO spacecraft. These small comets do not survive their perihelion passage. They mainly evaporate completely or some of them even hit the Sun. The identification of the C/2008 O1 comet had been somehow uncertain until I identified the comet in images taken by our second expedition group in Russia. Comparison of our images and images taken 19 minutes before showed the fast movement of the comet.
 
The visibility of the outermost part of the solar corona is highly over my expectation. The corona is traceable up to the distance of 20 solar radii. CME (Coronal Mass Ejection) was in the progress on August 1, 2008. The animation of images made by SOHO C3 coronograph shows that during the total eclipse the CME was rather faint. In spite of this, the CME is visible in the image but the contrast is very low. Therefore I made a small more enhanced B&W version of the image on which the CME is better visible and I compared it with SOHO C3 image taken at 11:18 UT. The result you may see here.
 
The position of the Moon represents the situation 62 seconds after the second contact i. e. 11:04:37 UT (18:04:37 local time). Display of the solar corona, lunar surface and stars in the resulting image are highly beyond the ability of human vision during the eclipse. You may download the highest resolution version of the image which I have here.
Click on the image or on the following reference to display the higher resolution image version (1.7 MB, PNG format).

ImageTse2008_200_mo1.png
Date01. 08. 2008
Time2nd contact 11:03:35 UT, 3rd contact 11:05:39 UT
Total eclipse duration 2 m 4 s
PlaceMongolia, Bor Udzuur
Coordinate45° 43.251' N, 92° 06.837' E, 1223 m altitude
ConditionsExcellent - clear sky, altitude of the Sun above the horizon 22°
OpticsCanon 2.8/70-200 mm L set to 200 mm (Canon EOS 5D)
Maksutov-Cassegarin 3M-6A, 6.3/500 mm (Canon EOS 350D)
CameraCanon EOS 5D (Hutech Ia modification) (ISO 100 and 200)
Canon EOS 350D digital camera (ISO 100)
Exposure1/125 s - 8 s
ProcessingComposition of 55 images (23 Canon EOS 5D, 22 Canon EOS 350D). 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, LDIC 5.0, Corona 4.1, Sofo ACC 6.1
OrientationImage must be rotated 9.6° clockwise to achieve standard orientation i. e. North up.
Copyright© 2008 Miloslav Druckmüller, Peter Aniol, Vojtech Rušin
 


Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
druckmuller@fme.vutbr.cz
Page last update: 23.10.2012