by owlice » Thu Dec 02, 2010 1:07 am
Fighting Light Pollution with the Computer
http://aljayani.ujaen.es
Credit: Josep Marti, Pedro L. Luque-Escamilla, and Jose Martinez-Aroza
[attachment=0]apod_proposal.jpg[/attachment][/i]
These two images show exactly the same view of the the whole sky as seen with a fisheye camera located in the Astronomical Observatory of the University of Jaen (UJA), Spain. The campus site is severely affected by light pollution coming from the nearby city of Jaen, as the left panel obviously shows. However the right panel features, at exactly the same time, an almost pristine sky where all city lights vanished as if a sudden blackout had occurred. But this did not happen. Instead, what actually happened was that the artificial light background was computer-subtracted. The same techniques that astronomers use at infrared wavelengths, where the sky background is naturally bright, were applied here but in the optical domain. A great amount of images taken by the automated camera (an All-Sky 340c from SBIG) were combined to produce an accurate estimate of the background light to be removed. As a result, stars up to 5th magnitude become visible as well as traces of the Milky Way next to the observatory dome. A video showing a full night of dark-sky images taken from the light-polluted UJA Campus can be watched at the videogallery available at
http://aljayani.ujaen.es
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[size=120][b]Fighting Light Pollution with the Computer[/b][/size]
http://aljayani.ujaen.es
Credit: Josep Marti, Pedro L. Luque-Escamilla, and Jose Martinez-Aroza
[float=left][size=80][i][attachment=0]apod_proposal.jpg[/attachment][/i][/size][/float]These two images show exactly the same view of the the whole sky as seen with a fisheye camera located in the Astronomical Observatory of the University of Jaen (UJA), Spain. The campus site is severely affected by light pollution coming from the nearby city of Jaen, as the left panel obviously shows. However the right panel features, at exactly the same time, an almost pristine sky where all city lights vanished as if a sudden blackout had occurred. But this did not happen. Instead, what actually happened was that the artificial light background was computer-subtracted. The same techniques that astronomers use at infrared wavelengths, where the sky background is naturally bright, were applied here but in the optical domain. A great amount of images taken by the automated camera (an All-Sky 340c from SBIG) were combined to produce an accurate estimate of the background light to be removed. As a result, stars up to 5th magnitude become visible as well as traces of the Milky Way next to the observatory dome. A video showing a full night of dark-sky images taken from the light-polluted UJA Campus can be watched at the videogallery available at http://aljayani.ujaen.es