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
    Name or NavList Code:
    Email:
       
    Reply
    What do stars look like in your eye?
    From: Jim Thompson
    Date: 2004 Apr 24, 08:55 -0300

    I wonder where my right eye's biological optics stand compared to
    experienced sextant-users.
    
    Stars appear to me in my sextant telescope as very slightly fuzzy pinpoints
    of light with a few sharp radiating lines projecting out of them.  The
    effect is less with higher magnification, but still there.  This makes
    finding dead center of the star image a little difficult for me.  What do
    you see?
    
    Venus last night was simply a bigger star-like image.  Frank Reed suggested
    putting the center of Venus on the moon's limb and accounting for SD, but
    there is no way that I could see that with my biological and physical
    optics.  Is that average or bad?
    
    Even with my 6x40 telescope, measuring index error on a fainter star results
    in an imprecision of +/- 0.1-0.3' on successive readings, in part because I
    cannot precisely see where the centers of the two images exactly coincide.
    I usually take about a dozen readings for IE, and always screw the index
    image down to the horizon image.
    
    Jim Thompson
    jim2@jimthompson.net
    www.jimthompson.net
    Outgoing mail scanned by Norton Antivirus
    -----------------------------------------
    
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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