It's hard to believe: we're now just one short weekend away from the big ticket astronomical event for 2017, as a total solar eclipse is set to cross over the contiguous United States on Monday, August 21st. Celestial mechanics is a sure thing in this Universe, a certainty along with death and taxes that you can bet on. There are a few key question marks come eclipse day, however, something that we can only speak with a few intelligent assumptions out 72 hours out.