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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: shortest twilight problem...
From: Marcel Tschudin
Date: 2010 Jun 29, 15:32 +0300
From: Marcel Tschudin
Date: 2010 Jun 29, 15:32 +0300
George, you were correct. The longest duration of twilight at given location is at a solstice, more precise at the summer solstice. I made a quick calculation for a location at about 41 deg North, the observer is 2m a.s.l., the atmospheric data are kept constant to standard 10C and 1010hPa. The result is as shown in the attached graph. I still have to understand why my reasoning which leads to the spring equinox is wrong. Marcel
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