Peer-reviewed analyses of Palomar Observatory plates from 1950–1956, led by Dr. Beatriz Villarroel and Dr. Stephen Bruehl, identified over 100,000 light-reflecting objects in Earth’s orbit decades before satellites existed, with statistical patterns showing they behave like real physical objects rather than photographic defects. The studies also found a significant correlation between these “mirror-like” transients and nuclear detonations, suggesting possible responsive or monitoring activity by

11 reactions | About the legendary telescope at Palomar Mountain. Video for Palomar Observatory and its bilingual virtual tour: https://www.astro.caltech.edu/palomar/visitor/media/palomartour/ | Palomar Observatory | Facebook

About the Palomar/Hale 200-inch mirror and its recoating process. Video for Palomar Observatory and its bilingual virtual tour: https://www.astro.caltech.edu/palomar/visitor/media/palomartour/ | Palomar Observatory | Facebook

Observatory Closure Notice The observatory will be closed to the public on Wednesday, 11/5, and Thursday, 11/6 while the 200-inch mirror is cleaned and re-aluminized. ✨ This special aluminizing process only happens every two years and is essential for keeping the telescope performing at its best. What is the aluminizing process like? It involves carefully removing, cleaning, and coating the giant mirror with a thin layer of aluminum to ensure maximum reflectivity — a truly fascinating behind-the

The Hale Telescope dome is the central feature on the Palomar Observatory compound, and a grand expression of architecture and engineering in its own right. Any development as large as the Hale dome has many contributors, and a team of nearly 100 workers were active for three years (1936-1938) realizing the Hale dome vision. Key contributions were made by Russell Porter who served as observatory principal architect, dome lead engineer Mark Serrurier, the dome steel structure contractor Consolida