Entry No. 13 — the San Diego file — filed under: outdoor

Palomar Observatory

The 200-inch Hale Telescope inside this Caltech-run dome was the largest in the world from 1949 to 1975, and its robotic sibling — the Samuel Oschin Telescope — is how astronomers found the dwarf planets Eris and Sedna out past Pluto. You can walk into the public gallery beneath the great dome and look up at the same mirror on a self-guided daytime tour, offered 9am-3pm most days (the scope does its actual sky-hunting at night).

The move: Hike the 2.2-mile Observatory Trail up from Palomar Mountain campground for sunset, then catch a guided dome tour (weekends, April–October) before the telescope crew opens the shutter for the night's real work.

• 📍 Palomar Mountain
• 💸 $
• ⚡ Low-key
• 🌗 Outdoors

Where: 35899 Canfield Rd, Palomar Mountain, CA 92060

Hours: Added 2026-07-19 — confirm current hours before you go.

Plan a visit & invite your people →

Further reading: sites.astro.caltech.edu · Wikipedia

last checked: 2026-07-19