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The total solar eclipse of August 21st, 2017 was observed with a DigitalSingle Lens Reflex (DSLR) camera equipped with a linear polarizing filter. Amethod was developed to combine images acquired with 15 different exposuretimes (from 1/4000 sec to 4 sec), identifying in each pixel the best intervalof detector linearity. The resulting mosaic image of the solar corona extendsup to more than 5 solar radii, with a projected pixel size by 3.7 arcsec/pixel,and an effective image resolution by 10.2 arcsecs, as determined with visible$\alpha-$Leo and $\nu-$Leo stars. Image analysis shows that in the inner coronathe intensity gradients are so steep, that nearby pixels shows a relativeintensity difference by up to $\sim 10 \%$; this implies that careful must betaken when analyzing single exposures acquired with polarization cameras.  Images acquired with two different orientations of the polarizer have beenanalyzed to derive the degree of linear polarization, and the polarizedbrightness $pB$ in the solar corona. After inter-calibration with $pB$measurements by the K-Cor instrument on Mauna Loa Solar Observatory (MLSO),data analysis provided the 2D coronal electron density distribution from 1.1 upto $\sim 3$ solar radii. The absolute radiometric calibration was alsoperformed, with the full sun image, and with magnitudes of visible stars. Theresulting absolute calibrations show a disagreement by a factor $\sim 2$ withrespect to MLSO; interestingly, this is the same disagreement recently foundwith eclipse predictions provided by MHD numerical simulations.

Coronal Electron Densities derived with Images acquired during the 21 August 2017 Total Solar Eclipse