, Louisiana, USA.]] Dusk or civil dusk is the time at which the sun is 6 degree below the horizon in the evening. At this time objects are distinguishable and some stars and planets are visible to the naked eye.[LINK: http://www.srh.noaa.gov/ffc/html/gloss3.shtml] Astronomical Terms at [LINK: http://www.noaa.gov/] National Oceanic and Atmospheric Administration Nautical dusk is when the sun is 12 degrees below the horizon in the evening. At this time, objects are no longer distinguishable, and the horizon is no longer visible to the naked eye. Astronomical dusk is the time at which the sun is 18 degrees below the horizon in the evening.At this time the sun no longer illuminates the sky, and thus no longer interferes with astronomical observations.

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