Sodium Lamps and Stargazing

January 13, 2004


Provided and copyright by: Laurent Laveder, Optics of the Atmosphere Gallery
Summary authors & editors: Laurent Laveder

Light pollution is disastrous for astronomy, but this problem can be made less troublesome by using alternative lightning techniques. For example, low pressure sodium lamps can be used (shown above) that lessen light pollution compared to conventional street lighting, such as mercury vapor lamps. Also, it's possible to use baffles or shields, which redirects light toward the ground rather than into space.

The above picture was taken on January 3, 2003, about 4 km from downtown Quimper (a city of about 65,000 citizens), in the Bretagne area of western France. A portion of the constellation of Taurus the Bull can be identified. The "v" shaped horns of Taurus (pointing to the right) can be seen near the center of the picture. Saturn is the bright object at lower left, near from Zeta Tauri. Note also, the familiar cluster called the Pleiades is visible at top center. This photo illustrates that even when street lights are present, the sky can be dark enough to allow useful observations, providing that the illumination is well designed.

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