NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2022 Aug 21, 18:36 -0700
If the issue is recording time, I find it's best to learn to count off ten seconds. Take your sight. When you like it, start counting at zero and reach for your watch. If it only takes you three seconds to grab it, you can keep counting but you have the advantage now of watching the seconds flip for the right cadence. When you hit ten, it's an easy and (nearly!) foolproof subtraction.
There's another use for a stopwatch. If you use Pub.249 Vol.1 "Selected Stars", you can use one single AP for a a round of sights if you shoot at exact four-minute intervals. That's because the Earth turns one degree in four minutes so you "wrap back" to the same AP longitude and drop down one line in the table (one degree of LHA of Aries) every four minutes. You take a sight and start the watch. Record the first sight and get ready for the second. You've got time. At the three-minute mark start setting up the second star. Glance occasionally at the watch, and when you have 10 or 15 seconds left, start counting those seconds down in your head. Try to finish swinging the arc and any final adjustment right on the four-minute mark. Repeat for another star or two.
Worth repeating: an error of one second of time in the sight is equivalent to an error of 0.25' of longitude which is 0.25·cos(Lat) nautical miles in the plot, and that's almost always negligible in celestial navigation. So the nearest second or two is plenty good enough.
Frank Reed
