Dark skies and bright constellations make this San Diego County park one of the best places for planetary spotting in the West. Low light pollution means crazy-clear views of the Milky Way, Saturn, and Jupiter. For a dark-sky sleepover, try a camping trip with California Overland, where starlit dunes are paired with campfire stories about the area’s history, and gooey s’mores come after dinner. From $225, including dinner and breakfast; californiaoverland.com
Best time to go: October, for spectacular star shows and clearest, balmiest weather.
Stay: Borrego Valley Inn has a small, sand-swept courtyard perfect for galaxy gazing. Plus, there are kiva-style fireplaces and a 4 p.m. homemade-cookie hour. From $205; 2-night min.; borregovalleyinn.com