Big Bear Solar Observatory

The white dome standing out in the water on a causeway is the Big Bear Solar Observatory, and it is out there rather than up on a peak because the lake solves the problem that ruins solar astronomy.

Look at the sun from dry ground and you are looking through the heat that ground is throwing off. Sunlight warms soil and rock, the soil warms the air sitting on it, and that rising, churning air smears the image before it ever reaches a lens. Water behaves differently. It takes the day's heat in instead of radiating it back, holds a stable layer of cool air above itself, and lets wind come across smooth rather than broken. Put the telescope a few hundred feet offshore and above the worst of the surface layer, at about sixty-seven hundred feet, in a valley with something close to three hundred clear days a year, and the seeing is as good as the mainland offers.

Caltech worked that out and built here in 1969 under the astrophysicist Harold Zirin. The New Jersey Institute of Technology took the site over in 1997 and runs it still. The main instrument is the Goode Solar Telescope, a 1.6-meter design whose mirror sits off to one side of the light path so nothing casts a shadow across the image. It took first light in December 2008 and was the largest working solar telescope anywhere until the four-meter Inouye telescope opened in Hawaii in 2020.

What it watches is weather. Magnetic storms on the sun arrive here as damaged satellites, disrupted radio and current shoved through power grids, and reading them starts with resolving the sun's surface finely enough to watch its magnetic fields move.

It is a working research station rather than a public one. The view is from the north shore, from the water, or from the highway along the lake, which is how nearly everyone has ever seen it.