Welcome to the NavList Message Boards.


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

Compose Your Message

Add Images & Files
    Re: "Vernier acuity" of horizon IC tests
    From: Greg Rudzinski
    Date: 2009 Jul 5, 20:53 -0700

    You may be confusing my average index error (which is an arbitrary
    amount that I like to keep below a minute of arc by adjustment) with
    the standard deviation of my data sets. The SD of .15' and .28' for
    the scopes used is less than your .4'cone size. This might be because
    of the magnification. My naked eye observations should be disregarded
    because of my in ability to focus on a distant horizon properly.On a
    good vision day I should be able to do better with the sight tube.
    On Jul 5, 3:31�pm,  wrote:
    > With consideration of the last posting regarding retinal receptors and vernier acuity:
    > I note the practical results of horizon index error measurement here by Mr. 
    Rudzinski, and of the results in the paper by Gordon; and the results posted 
    by others here, �amount to around 0.4 minute of arc to one minute of arc.
    > The cone diameter is about 0.4 minute of arc.
    > 'Normal' visual acuity (depending on the target type) is between 0.4 and one minute of arc.
    > Curious coincincidence, do you not think?
    > Douglas Denny.
    > Chichester. England.
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@fer3.com

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    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 Settings

    Posting Code:

    Custom Index

    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