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Thanks Hewitt,
 Your writing has always been fun to me, starting with my very first exposure 
to CN in your "Commonsense" book.(Thanks for that. My wife has other words 
for you though!)
You also got me on to using slide rules to do the math, "just for fun", which 
adds to my fun, sans smartphone (which is great but needs daily charging, a 
major negative in emergency survival situations).
My emergency grab bag contains an Otis King slide rule, miniaturised log 
tables, Greg's compact Daniol, and charts, Quartz watch set to GMT, Davis 3, 
Casio Fx-365OP programmable calculator with all the main methods 
pre-programmed in. (Very robust compared to a smartphone and does not require 
charging). Hope to  never have to use it, but I do practice runs 
occasionally, just for fun. 
Keep spreading the Joy Hewitt. 
Let's all have fun now. It's later than you think.
Francis.


-----Original Message-----
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Hewitt Schlereth
Sent: 01 October 2018 22:31
To: francis@pharmout.co.uk
Subject: [NavList] Re: Susceptibility of GPS to CME, Rationale for CN?

Francis, it's interesting that you and several others have cited fun as a 
raison d'etre for celestial, because at the beginning of the year, I changed 
the way I teach.

My course is now called The Joy of Sextant - Celestial Navigation for the Fun 
of It. Here I emphasize the two fundamental and enjoyable skills - using the 
sextant and the plotting sheet. The scut work of sight reduction is done with 
a smart phone app.

To give you the idea, here's the introduction of the booklet I developed and am using:

INTRODUCTION 

Seen as a whole, practical celestial navigation is divided into four parts:
Taking a measurement of the angle between the sun, the sea horizon and your 
eye, and noting the time you you did it. This is called "taking a sight."
Computing a comparison sight by one of several methods.
Comparing the sextant and computed sights.
Plotting the difference between your sight and the computed one on a special 
blank chart called a plotting sheet.
Until our century, doing steps II and III required a navigator to understand a 
fair amount of astronomy, geometry, trigonometry, math, and do a lot of 
arithmetic. It was quite a bit like doing a tax return, i.e., tedious.

Nowadays a smartphone app can do the scut work of parts II and III, - "letting 
George do it," so to speak - leaving you the enjoyable parts.

Too, once the app is in your phone, it does not need internet or satellite 
connections. It's self contained. So, it's also a first step away from GPS 
dependence. 



Hewitt





 



On Oct 1, 2018, at 11:15 AM, Ed Popko  wrote:

I have to agree with Dave overall point.

I find celestial navigation extremely rich. I don't own a boat (anymore) and 
never did deep water sailing when I did.  But it doesn't matter. What's 
important, to me anyway, is the beauty of form of applied obserational 
astronomy. For me, that's justification enough.  It's a wonderful medium to 
learn and appreciate the sky as well as the evolution of technique and 
equipment.

Much of what man does with nature is distructive. We are quite skilled at 
destroying nature - consuming, extracting, hording, poluting. But CelNav is 
different. It's all about information - extracting angles, relationships, 
visibility, timing, direction.  There's something quite elegant here. 

And then there is the other dimension, time and history. CelNav opens so many 
doors to maritime and aviation history, science, innovation and 
personalities.

But perhaps the simplest reward is the confidence you can figure out where you 
are and what time it is (Lunars).

So, when my wife sees me in the back yard taking shots and quips "Has the 
house moved?" I just think of what she misses.

Popko



: 
http://fer3.com/arc/m2.aspx/Susceptibility-GPS-CME-Rationale-for-CN-Schlereth-oct-2018-g42957

   

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