Local Street Lights - Frank Johns

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Local Street Lights

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Local Street Lights
As part of its cost reduction programme, my local authority, Cornwall Council, has embarked on a major upgrade of all street lights. The lights on the main roads were a mixture of high and low pressure sodium lamps. 

The new luminaires have a much shorter and higher intensity bulb and are fitted in a holder which almost eliminates the horrizontal/vertical spread of the light. The light pollution is dramatically reduced. Furthermore each lamp can be individually addressed and its brightness reduced or raised. This is done remotely, via a wifi link, apparently. 
The previously installed sodium lights to the SW of the observatory
The new luminaires in action

Whilst the new luminaires have a much lower spread of the light than the old sodium lamps, the spectrum of the new is much more spread across the range. The comparitive spectra are shown in the graphs, and it will be seen that it will actually be more difficult to obtain filters to cut emissions from the new lamps because of the wider spread.
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