# 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: Chronometer Suggestions
From: R B Emerson
Date: 2009 Jan 6, 07:12 -0800

```Yewbetcha!  At the equator, every minute of error is one nautical mile
and that makes a second's error about 100 feet.  Given that a really
good round of sights at sea might be good to a mile or two, where's
the problem?  The problem is that these errors can become cumulative.
And even if they're not, navigation is all about accuracy; if timing's
sloppy, what else might be sloppy, too?  Sooner or later, the boat is
put at risk because of all the slop.  Not Good.

(Why "at the equator"? Because the higher the latitude, the smaller
the distance covered by a degree of circumference.  The nautical mile
is derived from the Earth's circumference at the equator divided by
360 degrees.  Measure the Earth's circumference at, say, 45N, and the
number of miles is less but there are still 360 degrees to that
circumferential circle.)

Cheers,
Rick

On Jan 6, 8:05�am, William Sellar  wrote:
> As a beginning celestial navigator, I am wondering how much time and watch
accuracy is actually required for practical navigation.� Can we predict how
many miles off one would be for every second of time error?
> �
> Bill
--~--~---------~--~----~------------~-------~--~----~
To post, email NavList@fer3.com
To unsubscribe, email NavList-unsubscribe@fer3.com
-~----------~----~----~----~------~----~------~--~---
```
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)