# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding

Message:αβγ
Message:abc
 Add Images & Files Posting Code: Name: Email:
Re: Another "emergency navigation" sight reduction method
From: Hanno Ix
Date: 2015 Jul 5, 13:03 -0700
Greg,

you might be able to improve N(x) by a factor of 2 if you made another N(x), call it NN(x), where the N(x) values are doubled. They then would be even numbers and particularly easy to interpolate. The absolute values of N(x) or NN(x) do not matter, just their ratio does. NN(x) would not need more space.

If you can spare extra space your 10min version is of course much better. However, you might now have to increase the digits of the N(x) entries to 5 to support that higher resolution.

H

On Sun, Jul 5, 2015 at 10:51 AM, Greg Rudzinski wrote:

What is acceptable precision for get home or rescue position CN ? At a minimum I would like precision at less than 10' of arc. The N(x) tables would be better if expanded to every 10' of a degree. Now to decide what micro kit to put with a Davis MK 3 for emergency.  The Sun LTA from Pub 249 Sun would be a good choice. For sight reduction there are some interesting options. N(x), 3 place haversine Doniol, 6" pocket slide rule using classic trig. Best to try each and decide. This morning several Sun reduction simulations were done by plastic pocket 6" Doric slide rule using the classic trig sin cos formula. Results were all within 10' of the calculator reduction when Hc is less than 50°. If the 6" slide rule is to be a choice then do not forget to include reading glasses with the kit.

Greg Rudzinski

Attached File:

(Pocket-SR-Emergency-CN.jpg: Open and save)

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)