Clear Sky over Niagara

At night, by treaty, the minimum flow over Niagara is cut in half. Under a 1950 agreement between the United States and Canada, at least 100,000 cubic feet of water a second must go over the falls during daylight in the tourist season, April through October. At night and through the winter the minimum drops to 50,000. The rest goes through tunnels and canals to the power stations.

The falls have been on the job since the 1890s. In 1895 the Adams power plant began generating alternating current on Nikola Tesla's system, with generators built by Westinghouse, and in November 1896 its power reached Buffalo over a line about 25 miles long.

Since 1925 an international board has floodlit the falls after dark, and two cities glow along the gorge. This picture turns all of that off and leaves the sky.

The Milky Way arcs down from the upper left toward the far bank, bright against deep blue. Below it the water has been softened to silk: a straight fall on the left, close to the viewer, and a wider crest beyond it vanishing into its own mist. A pale blue glow sits in the spray at the lower left, and a few warm lights show on the far shore to the right.