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: Ken Muldrew
    Date: 2004 Apr 25, 22:19 -0600

    Ken Muldrew wrote:
    
    > When the telescope is centered, and the sextant is rotated so that
    > half the sun vanishes, removal of the paper does not affect the image
    > whatsoever.
    
    I just did this with the moon, with no shades or anything to interfere with
    the image, and I now see what you see. When the paper is removed from
    the glass, there is a reflection that is as bright, or nearly so, as that
    coming from the mirror. I don't know why it didn't work with the sun, but I
    think it was due to an error on my part. The reflection past the middle of
    the field of view is a combined image from both the mirror and the glass
    until the object is rotated past the point where the scope can no longer
    get reflected light from the mirror. Then the image comes solely from
    reflection off the two glass surfaces. The transition is imperceptable with
    a 5x scope.
    
    George Huxtable was entirely correct in this matter and I thank him for
    sticking with it until I was able to understand the phenomenon.
    
    Ken Muldrew.
    
    
    

       
    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