# 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:
Re: An azimuth formula that works everywhere? Even on poles?
From: David Iwancio
Date: 2021 Jul 20, 12:09 -0700

Tony:

Consider:  if you follow a rhumb line at 090° or 270°, you are effectively moving along a circle centered around the poles.  If you follow such a course at latitude 89°59'59.99", you are going to get dizzy.  If you're "moving" east or west at latitude 90° you are effectively spinning in place, and if your location is treated as an infinitessimal point, then we enter a philosophical debate over whether an infinitessimal point can "spin."  Regardless, any direction, any change of position away from latitude 90° is necessarily going to be along a meridian (which all meet at the poles).

Another way of looking at this: you can't determine the hour angle of a body from latitude 90° because you don't have an hour angle.  You are simultaneously standing on all meridians, all hour angles, so the body's "local" hour angle is meaningless.

Your longitude is indefinite, so any formula you use will produce the indefinite result of dividing by zero.

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)