Elgin National Watch Company Observatory
From Wikipedia The Elgin National Watch Company Observatory was built in 1910. It is the last remaining significant structure closely associated with the famed pocket watch company. Watchmakers ran into a common problem in those years in that there was no standard time. In 1908, President Theodore Roosevelt mandated that the US Department of Standards encouage common and accurate timing across the nation. Watchmakers were forced to find a way to ensure accurate timing of their watches. Elgin National responded by constructing an observatory. With an observatory, Elgin National could track sidereal time, the measure of the Earth's rate of rotation relative to the stars. This was compared to measurements of solar time, based on the sun's position in the sky. These two measures combined to make Elgin National's watches accurate within 1/100th of a second.
