A substance is anhydrous if it contains no water, for example, salts lacking their water of crystallisation. The way of achieving the anhydrous form differs from one substance to another.
A partial solar eclipse at its peak at 3:37 p.m. in Mesa on Oct. 23, 2014. The eclipse was visible over most of North America and covered 44 percent of the Arizona sun. Michael Chow/The Republic.
The September 28, 2015 Total Lunar Eclipse is the fourth and final eclipse in a series of four total lunar eclipses called the lunar tetrad. The first three eclipses of the tetrad took place on April 15, 2014, October 8, 2014 and on April 4, 2015.