This image of Milan taken by astronaut
Samantha Cristoforetti from aboard the International
Space Station was acquired after the transition to LED technology in the centre . The illumination levels appear to be similar or even brighter in the centre than the suburbs , and the amount of blue light is now much higher , which suggests a greater impact on the ability to see the stars , human health and the environment .
Light pollution :
COURTESY OF NASA / ESA
The unrelenting bane of the amateur astronomer
By COLIN HENSHAW
Guest Contributor
In centuries past there wasn ’ t any electric lighting . The only lighting that was available was provided by oil lamps and candles , which in some communities were used to illuminate streets . The lighting was only provided on a must-need basis and was relatively unobtrusive . The astronomers of the day would actually observe from town centres , as evidenced by the Rundetaarn ( the Round Tower ) in Copenhagen , Denmark 1 . The Royal Greenwich Observatory was located in Greenwich , which at the time was a village outside London . The 19th century brought gas street lighting , which again was relatively unobtrusive , and this persisted in some areas right into the 1960s . However , toward the end of the century advances were made in electric lighting technology , and this was used to replace the gas lighting that was used to light streets . Even so it was still relatively unobtrusive , and was confined mainly to urban areas . However , it was beginning to affect astronomers , and staff at the Royal Greenwich Observatory found they could no longer function effectively from the increasingly light polluted skies of London . They felt obligated to move and relocated to Herstmonceux in rural Sussex , not far from the coastal resort of Eastbourne . The Godlee Observatory , located in the old University of Manchester Institute of Science and Technology , in the centre of Manchester , was built at the turn of the 20th century , and is the base for Manchester Astronomical Society . It would have given some fine views of the night sky . It is still in use , but light pollution from the city renders it useful only for observing the Moon and the brighter planets . In the latter half of the 20th century , street lighting began to expand , and by the late 1960s , after the widespread introduction of sodium lighting , it became so widespread that the cloud deck above cities began to glow orange . It was obvious now that there was a serious environmental problem . Astronomers , however , are a placid group of people and not given to political agitation , so for many years they suffered in silence . On the rare occasions when they did complain , they would be regarded as eccentrics whose concerns could be trampled upon with impunity . It was always said that street lighting was needed to reduce crime and improve safety . Those that could , would observe from their back yards or from local parks where lighting was less obtrusive , or would go on holiday to dark locations . Dark skies in the U . K . were still available in the wilder parts of the U . K . right into the 1970s . By the end of the 1980s , light pollution globally was expanding at such a rate that dark skies in many areas
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