WHERE: Mount Palomar, Calif.

WHY GO THERE: High in a mountain meadow, the 200-inch Hale telescope hums quietly beneath its massive dome.

Dedicated in 1948, the telescope was the largest, most effective telescope in the world until the Keck 1 on Mauna Kea was completed in 1993.

By 1948, the telescope's huge lens, manufactured by Corning Glass using its (then) new heat-resistant Pyrex glass, had been carefully shipped cross-country to be ground and polished for two years. Meanwhile, other parts for the scope had been manufactured in shipyards —the only workshops at the time able to build to that scale.

Three other smaller scopes are housed at the summit, including the Samuel Oschin Telescope, credited in 2007 for discovering Eris, the 10th planet to orbit the sun.

WHAT TO SEE: Visitors can stand on the perimeter gallery surrounding the Hale telescope to view the big instrument. Though the Palomar Observatory is an active research facility (meaning Caltech, Jet Propulsion Laboratory and Cornell University scientists may be observing at night), visitors can take self-guided tours of the 200-inch telescope from 9 a.m. to 4 p.m. daily. But take a sweater — the dome is calibrated to nighttime temperatures on the mountain, so even at midday in midsummer it's chilly.

ALSO THERE: Mount Palomar is a state park with year-round camping, hiking and cycling trails. The word palomar is Spanish and means "pigeon house," which is thought to reference the large shoals of pigeons seen during the spring and autumn months atop Palomar Mountain.

WHERE TO EAT: At the summit, Mother's Kitchen makes homemade vegetarian breakfasts, lunches and picnics to go. 760-742-4233, www.mothers kitchenpalomar.com. The Palomar Mountain General Store next door sells gifts, groceries and camping supplies. 760-742-3496, www.palomarmountainstore.com.

GETTING THERE: Mount Palomar Observatory is at 35899 Canfield Road, off Route 76 in northern San Diego County. That's about a two-hour drive from downtown San Diego, and a three-hour drive from central Los Angeles. The winding road through the Palomar Mountain Range and the scenery up to the observatory make it a journey well worth taking. 626-395-4033; www.astro.caltech.edu/palomarnew.