End of the Blue Hour: San Francisco

A history of design and engineering is visible from the Marin Headlands in the Golden Gate Bridge and San Francisco beyond it. That’s visible at every hour of the day, so I must conclude that the people jamming the roads earlier on the evening of this image were mostly there for the combination effect with the sunset. As the crowds decamped for dinner elsewhere, the blue hour brought my favorite views of the city.

End of the Blue Hour: San Francisco

532 nm

In St. Lawrence’s Raman spectroscopy and microscopy lab, the most potent laser illumination source comes from a neodymium-doped yttrium aluminum garnet. This is a pretty ubiquitous laser source, but I happen to like it because it also demonstrates the value of nonlinear optics: though this laser is emitting light at 1064 nanometers (in the infrared), a suitable doubling crystal can combine two of those 1064 photons together to make a shiny new 532 nm photon.

532 nm

Skytop and the Hotel

Mohonk’s Skytop appears as a small castle atop the hills near the hotel, but its reality is a bit more mundane: it was constructed as a watchtower for forest fires in the early twentieth century. Though no longer in use, it adds an extra hint of magic to the whole setting. The hotel (off to the left) sits on the water, and the tower touches the sky.

Skytop and the Hotel

No More Canoes

There are many ways to define the seasons, with varying degrees of usefulness. (Solstices and equinoxes seem to have only the thinnest connection with the weather.) Perhaps the most valuable differentiation between times of the year is when one can reasonably be out on the water: “Spring” is that first moment when an afternoon in a canoe doesn’t sound miserable.

No More Canoes