Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Polaris for Latitude- why so accurate?
    From: Greg Rudzinski
    Date: 2014 Sep 27, 11:39 -0700

    Sam,

    Is your AH a leveled mirror type ? Or are you using a bubble optic attached to your sextant ? A water or oil AH limits me to only very bright stars such as Sirius. If you are using a bubble then 1' intercepts are exceptionally good. If using a well leveled mirror or water (oil) then 1' or better is to be expected. 

     

    Polaris changes altitude very slowly just like the Sun at or near LAN. This gives the observer plenty of time to center the body in the center of the scope field and find a perfect vertical to to the horizon. Timing is not needed to the second for Polaris. As a matter of fact you will do well even rounding the LHA of Aries to the nearest degree for entry into NA tables. The main problem with Polaris at sea is that there is a very bief window during twilight where both Polaris and a sharp horizon are visible.

     

    Greg Rudzinski

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    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)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site