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: Are higher altitude sights inherently less accurate?
    From: Geoffrey Kolbe
    Date: 2012 May 02, 20:50 +0100

    When a star is near the horizon, there is no problem in knowing which
    direction to face to measure its altitude.
    
    But suppose you are measuring the altitude of a star on your zenith.
    The altitude will be 90 degrees. Which direction do you face to
    measure the altitude? When a star is on your zenith it doesn't
    matter, of course. You can face in any direction.
    
    But now suppose the star is a degree away from being on your zenith -
    how to you figure out which direction to face to measure its altitude
    then? You can see that without paying very careful attention to the
    direction you face (the azimuth) you could easily be out by a couple
    of degrees in the star's altitude!
    
     From this example, I hope you can understand that as the altitude of
    a celestial body increases, the greater the difficulty in determining
    the azimuth at which you should measure the altitude of the body.
    (Too, the error how vertical your sextant is becomes rapidly more
    important). And in consequence, errors in high altitude sights will increase.
    
    Geoffrey Kolbe
    
    At 15:23 02/05/2012, you wrote:
    
    >I have been loking at averages of my sights and higher altitudes
    >seem to have larger intercepts. Using an AH and reading Hs of over
    >100 degrees, Ha over 50. It seems to take longer to find high
    >altitude bodies in the mirror but is there something in the process
    >which introduces more risk of error?
    >----------------------------------------------------------------
    >NavList message boards and member settings: www.fer3.com/NavList
    >Members may optionally receive posts by email.
    >To cancel email delivery, send a message to NoMail[at]fer3.com
    >----------------------------------------------------------------
    
    
    
    
    

       
    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