Earthwalk Day 1269 (14 July 2025), 12,645 km: Palomar Observatory

Leg 48 ended today with arrival at a truly iconic place. When I was a kid, my parents took me to the Corning Museum of Glass where among other things I saw a huge piece of glass — a disk 5.1 meters in diameter. This was the result of the first attempt, in 1934, to cast a blank for what would be the world’s largest telescope mirror. But part of the mold broke during the pouring. The second attempt was successful. The first blank went on display at the museum in 1951. The second became the primary mirror of the Hale Telescope at Palomar Observatory.

The Hale held the record until 1976, so it was the biggest in the world throughout my childhood. I may not have known much about many telescopes, but I knew about the Hale.

It was among the first to detect the high redshift of quasars. It was the first to detect Comet Halley on its way to its 1986 appearance. It was used to discover two moons of Uranus and one of Jupiter. It has directly imaged exoplanets.

It’s not still the biggest telescope, but it’s still there. So (virtually) was I, today. Now I’m 4 km away, starting on Leg 49.

A map showing my progress is here, a spreadsheet with progress detail is here, and a Google Earth KMZ file is in this Google Drive folder. Present coordinates: 33.345°N, 116.873°W.