This large field of view image was recorded with a Nikon Z6 with Nikkor 85mm f/1.4 lens. The lens was used at full aperture and the camera body used at base ISO to gather the maximum amount of light and get best SNR. Altogether, the Nikon Z6 and its fast XQD card allowed to capture more than 300 frames during the totality, with exposure from 1/25s to 0.7s.
The inner corona was recorded with the high resolution setup while area below horizon was recorded with a shorter focal length setup. Altogether, 2186 frames (646 images acquired during the totality with lenses and telescope, plus 1540 additional calibration frames), were used to create this unique high dynamic range composite. It was very tedious and time consuming task, but totally worth the personal investment.
The resulting image has extremely high dynamic range and signal to noise ratio and thus contains a lot of details, but those are hidden by the light of the blue sky during the eclipse. In order to reveal these hidden details, it was necessary to subtract the light from the blue sky similarly as what astrophotographers are doing in order to remove the effect of light pollution.
Then, an incredible sight is revealed, with the full extend of the solar corona, the numerous stars of the Milky way in the background, some of them of magnitude 10, but also the light of the coastal city of La Serena located more than 50km away, and extremely thin clouds structures that were not visible visually.
All of this definitely makes the image above my wildest expectations.
Enhanced large FOV image of the total solar eclipse from Cerro Tololo (high res here). At the time of the eclipse, The sun was in the foreground of the Milky way, hence the very rich star field. The lights of the city “La Serena” located 50km away are still visible despite the distance.
Natural version of the HDR composite without enhancement which recreates very well the visual appearance of the eclipse as seen from Cerro Tololo (high res here). The planet Venus was the only “star” visible in the vicinity of the eclipse.
Closeup view of the extend of the solar corona during the eclipse (high res here). The equatorial jet of the corona can be traced up to a distance around 40 solar radii above the sun, and around 25 solar radii toward the horizon.
The image reveals also very well the two components of the solar corona visible during eclipse. The inner corona, with plasma structure and jets that is the outer atmosphere of the sun (K corona), and a diffuse, large and slightly redder component (F corona) that is not actually linked to the sun but is created by light from the solar surface scattered by interplanetary dust located between Earth and Sun, exactly like a intermediate thin fog would scatter a diffuse glow around the bright sun. Although the sun atmosphere (K corona) appear bluish on the image, it is actually the same color as the sun surface.
On the left hand side: the natural composite of the eclipse; in the middle, the solar corona with the light from the blue sky subtracted; on the right hand side, saturation increase of the solar corona after blue sky subtraction showing the distinct colors of two components of the solar corona from the plasma of the solar atmosphere (K corona) with jets and coronal features and from the interplanetary dust (reddish F corona) which is a roughly circular featureless glow (high res here).
Sketch (not to scale) explaining the actual location of the two distinct components of the solar corona.
This image was made possible thanks to Jean-Luc Dauvergne (Ciel & Espace), Shari Lifson and the great team of CTIO and AURA, and Nikon France for trusting in the project and lending the camera and lens used for making this incredible image!
Thanks everyone!
HDR astrophotography by Nicolas Lefaudeux 