An observer in or near the path of totality for the April 8 solar eclipse, can make useful observations of the appearance of the moon's shadow projected on the Earth's atmosphere, before, during and after mid-eclipse. Also, valuable can be studies of sky darkness.
At the time of a total eclipse, the moon's shadow cone intersects the ground in an ellipse, its major (long) axis pointing in the direction of the sun. Because the shadow is moving rapidly, its appearance continually changes. Careful descriptions of the sky from moment to moment near totality can be of interest, particularly observations of the moon's shadow seen against the sky as it approaches just before totality and recedes just after.
