The Transylvania Times -

Ask Us: Sunrise, Sunset & Twilight

 


What is the difference between sunrise and sunset, civil twilight, nautical twilight and astronomical twilight?

According to Dr. Bob Hayward, astronomer and educator with the Pisgah Astronomical Research Institute (PARI), Sunrise and Sunset are the times when the upper limb of the sun is first/last on the horizon. In tables it is usually given for an observer at sea level. Observed times may differ due to the observer’s altitude and, of course, the observer must have a clear horizon. Astronomers refer to the horizon 90 degrees from straight overhead, i.e., the zenith, as the astronomi...



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