A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2019 Jan 19, 13:15 -0800
Jackson, you wrote:
"1. Finish reading the American Practical Navigator (Bowditch), 1966 edition, which is, I understand, the last edition to give pride of place to celestial navigation."
Nooooo!! Bowditch is a reference book, one among many. Actually reading Bowditch is like reading the manual that came with your VCR (how long was that one your New Year's Resolution list? ;-) ). There are plenty of interesting, educational books on navigation. Not Bowditch.
"2. Achieve a better understanding of spherical trigonometry."
That's a lot less useful than you may imagine.... I'm reminded of the game of pool (billiards). Twenty years ago, I used to be quite a skilled pool player. At a certain point, I learned a key philosophy of the game, and I also learned what sunk most people who wanted to play better. When you first learn pool, you learn how to shoot a set of basic, easy shots. You get good at those easy shots, and you say to yourself, "I want more... I'm going to focus on difficult shots now!" And many people listen to that inner voice, and they spend ages laboring over difficult shots, "trick shots". Maybe they even get clever at some of those. But if you watch a really good player, they never shoot those shots because they seem to have (as it appears to the intermediate player) amazing luck. Everything comes easily to them, and there are no difficult shots! That's because they turned left at the fork in the road when the other player turned right. A good player does not decide to focus on difficult shots. A good player instead learns how to make every shot easy... guiding the cue ball to the perfect location so that there are no difficult shots ever.
Solving problems in celestial navigation is similar. You do not learn a little spherical trigonometry and then advance to lots more spherical trigonometry. That's not how you get better at the problems of navigation. Instead, you learn to see the easy, standard problems of spherical trigonometry inside every problem that you examine. Learn the standard fundamental rule of spherical trig --the basic cosine law. Memorize it so that you can write it down without looking it up. See how it applies to every case that you may encounter. Great circles... altitudes... lunars... it's all the same. But there's no need to focus on re-deriving these things since every conceivable case has already been analyzed. Learning how the math works, learning about the math is what you need. Trying to become a spherical trig mathematician is the same as the pool player who takes the wrong turn at the fork in the road and focuses on trick shots... You'll never become an expert on that path.
For what it's worth, I never teach spherical trigonometry in any of my classes except "lunars" and "advanced celestial". It's un-necessary background. I also wouldn't teach binary numbers to folks learning to use spreadsheets...
PS: Please see the updated schedule of classes on my website. I'm teaching some workshops this Winter and Spring at Boston Community Boating in Boston, MA and also at the Hudson River Maritime Museum in Kingston, NY. These new venues are in addition to classes at Mystic Seaport Museum in Mystic, CT.