# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Message:αβγ
Message:abc
 Add Images & Files Posting Code: Name: Email:
From: Hewitt Schlereth
Date: 2016 Jan 20, 17:21 -0800

Bob, here are photos of a cel Nav slide rule I made by putting the slide from K&E 4070–3 into the body of a a 4090–3. As you see, the 4090-3 has the trig on its body; the 4070-3 has them on its slide. Really saves steps when solving the sin/cos formula for Hc.

Hewitt

On Jan 20, 2016, at 12:22 PM, Bob Goethe <NoReply_Goethe@fer3.com> wrote:

Great idea, Gary, but easier said than done.  The only really good image of deg/min scale I found today was from the Podmore book, where he illustrated the Academy Duplex 504. The Academy 504 has digits marking each degree between 10° and 20° on the tangent scale.  When I compared that to the decimal illustration I had, the deg/min model looked vastly more busy to me.  I thought that would skew a collective assessment unfairly in the direction of decimal degrees.

I went and manually deleted the numbers from my screen capture, to try and get closer to oranges and oranges.  But the only way to really do this well is to get control of the tangent function with VBA and Corel (which I have yet to do), and produce the scales as you wish.

Failing that, the best one can do is to compare oranges, so to speak, with other similar-style citrus fruit.   If we are reduced to using images we came up with in Google searches, and imagining what it could look like...well, we can all engage in that sort of imaginative exercise.  I am not the only one who can set the visual parameters of the comparison we use as a discussion point.

Bob

View and reply to this message

Browse Files

Drop Files

### Join NavList

 Name: (please, no nicknames or handles) Email:
 Do you want to receive all group messages by email? Yes No
You can also join by posting. Your first on-topic post automatically makes you a member.

### Posting Code

Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
 Email:

### Email Settings

 Posting Code:

### Custom Index

 Subject: Author: Start date: (yyyymm dd) End date: (yyyymm dd)