Thursday, October 19, 2017
The ASA Douglas style 5" by 5" compact plotter is perfect for small craft chart tables. Customize with 1.5mm drilled holes in the center and at the upper scale. This will enable DR and celestial navigation plotting without the need for dividers. Includes reciprocal courses around the perimeter compass rose.
Sunday, October 8, 2017
The Otis King is a basic non electronic calculator with four place precision and is good enough to perform law of cosine sight reduction to 1' for celestial navigation and great circle sailing purposes. Easy to learn multiplication and division routines. Find for reasonable cost on Ebay.
Saturday, July 8, 2017
Monday, April 10, 2017
Affordable quality mechanical watch movements such as ETA, Seiko, Miyota, and Orient can be rate adjusted to better than 5 seconds per day using a free program called Audacity. There is a learning curve to it. The how to YouTube videos are helpful. See links.
An excellent affordable mechanical watch suitable for underway celestial navigation is the Orient Ray II divers model which hacks and hand winds.
The Orient Flight model is another very accurate mechanical watch which would fit the navigation roll. This model doesn't hack or hand wind but is very easy to read in all light conditions.
Tuesday, January 17, 2017
Here is a link to a useful Bowditch style compact ex-meridian table PDF designed primarily for Sun observations.
Sunday, September 4, 2016
The ex-meridian calculation can be performed faster by slide rule than by pocket trig calculator with equal precision for celestial navigation purposes. 5 moves of the cursor and 6 moves of the slide in less than 2 minutes of time.