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: How does the AstraIIIb split mirror work?
    From: Fred Hebard
    Date: 2004 Apr 23, 17:43 -0400

    On Apr 23, 2004, at 5:14 PM, Ken Muldrew wrote:
    >
    > Because the light coming down from the index mirror is not
    > perpendicular to the horizon glass, the reflections from the front
    > surface and back surface will be vertically displaced, due to the
    > horizontal displacement. The reflected rays will be parallel, but
    > displaced vertically. I just got a piece of plexiglass (9mm thick,
    > but close enough) and verified that. By changing the angle of
    > incidence, one can change the separation. One reflection is
    > significantly brighter than the other, but they are both clearly
    > visible. I don't see that in a sextant.
    
    I've seen it.
    
    Fred
    
    
    

       
    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