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: Emergency Meridian Altitude
    From: David C
    Date: 2016 Dec 9, 11:54 -0800

    Intuition told me that the longer the pole (not sure if it is called a gnomon) the less the effect of measurement errors. I decided that I could measure to an accuracy of 1mm. The base value is  height  370mm   length shadow 121mm.  If I change the height by 1mm the altitude changes by 2.6'. I then calculated the error for multiples of the base value.

    x1  2.6'

    x2  1.3'

    x3  0.9'

    x4  0.4'

    It seems the longer the better but........the longer the pole the bigger the error due to it not being vertical. I haven't worked that out yet. There must be an optimum pole height to minimise error.

       
    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