# NavList:

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

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Re: Beginner Meridian Passage Question
From: Zorbec Legras
Date: 2004 Sep 3, 11:31 -0500

```----- Original Message -----
From: "Noyce, Bill"
Date:         Fri, 3 Sep 2004 09:13:03 -0400
Subject:      Re: Beginner Meridian Passage Question

> > > b) when you think Polaris is directly below or above the pole, add
> or
> > > subtract its difference (which you have memorized as about 45');
============================

Latitude by pole star.

Lat = true altitude + corr 1 + corr 2.

Corr 1 = Pd * Cos LHA
Corr 2 = ((sqr Pd)/2.3438) * sqr sin LHA * tan true altitude.

Pd = pole distance = 90 - dec.
============================

Latitude by meridional transit.

Upper transit:

Lat = Zd + dec (1)
Zd = zenithal distance (= 90? - true altitude).
+ Zd if elevated pole in your back
- Zd if your are facing elevated pole.

+ dec if same name as latitude
- dec is diff name.

Lower transit

Lat = 180? - (Zd + dec)

==============================

Ex meridian (if you miss the transit)

Vers meridional Zd = vers (90? - true altitude) - (vers LHA * cos assumed Lat * cos dec)
with the meridional Zd use formula (1) to compute the Latitude.

Vers x = versine x = sinus verse x = 1 - cos x
==============================

About the elevated pole, have a dry gin and read it again...

The elevated pole is the pole in the same hemisphere as the zenith.

==============================
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```
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