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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The Dunlap Sunrise Sunset Computer
From: Gary LaPook
Date: 2017 Sep 20, 08:40 -0700
From: Gary LaPook
Date: 2017 Sep 20, 08:40 -0700
- Nope, it's selfcontained. Just place the template for your latitude, set the index for the date and then rotate the template until the zero degree altitude curve intersects the analemna where it touches the ecliptic and then read out the time of sunrise or sunset. You can do the same with the minus 12 degree curve (that I added) and read out the time of nautical twilight which also then tells you the LHA Aries so you can go directly to HO 249 volume 1 to precomute the altitude for presetting the sextant so that you can more easily spot the stars soon after sunset.
gl
