At 6,800 feet in altitude, McDonald Observatory atop Mt. Locke in Ft. Davis, Texas, enjoys some of the clearest and darkest skies in the continental United States. At the Frank N. Bash visitor's center, public star parties are held on the site on Tuesday, Friday and Saturday evenings. This is a composite photo showing the phases of the moon from a day after new moon (right bottom) to full moon (left bottom).