Moon with amethyst hues during full eclipse from tropical region

We report on the first documented observations, to the best of our knowledge, of the amethyst (super wolf) Moon recorded in the region just south of the northern Tropic of Cancer (latitude ${21}^\circ {7.745^\prime}\;{\rm N}$21 ∘ 7.745 ' N), at about 2000 m height above the sea level during the lunar eclipse on 20 January 2019. During the color transition from the brownish red to amethyst blue (a mixture of dark blue and some red), the moon in the center of the Earth shadow (mid-eclipse) was nearly in zenith in Leon, Mexico. We interpret the amethyst color as arising from the inability of red rays to curve into the axial regions of the lunar spherical surface, while the scarce, randomly distributed blue rays are still incident there.