MEDORA — Theodore Roosevelt National Park will welcome visitors for two days of stargazing, hands-on science activities and astronomy presentations during the annual Dakota Nights Astronomy Festival Aug. 14-15. Activities begin at 2 p.m. each day on the South Unit Visitor Center lawn, with programs designed for visitors of all ages. Both evenings will conclude with telescope viewing from 8:45 to 11:30 p.m. at Peaceful Valley Ranch, located at mi…