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: Simplified Bris Sextant
    From: Alexandre Eremenko
    Date: 2012 May 7, 23:15 -0400

    Greg,
    
    I have to say that I do not find this Bris very practical.
    It is rather a toy than a navigation device.
    The reason is that you have to wait for these pre-assigned moments,
    there are few of them during the day, and at these moments
    Sun can be obscured by a cloud, or you can be busy with something
    else, or just miss the moment.
    
    I am interested to hear from a list member who managed to
    gratuate his/her Bris sextant:-)
    
    Alex.
    
    On Mon, 7 May 2012, Greg Rudzinski wrote:
    
    >
    > Making a simplified Bris  Sextant only requires gluing two microscope slides 
    together with a gap at one end. The larger the gap the greater the angular 
    deflection of the reflected Sun. I used a 0.7 mm pencil lead to set a gap and 
    got 1* 57.8' of deflection. Inspect the linked image and you will see that 
    the reflected image is the sum of four images one on top of the other. This 
    must be from the front and back surface reflections from each slide. The best 
    a navigator can probably hope for is 1' to 2' of precision on a home made 
    version. Still this is pretty good for something that can get lost in a shirt 
    pocket.
    >
    > Greg Rudzinski
    > ----------------------------------------------------------------
    > 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
    > ----------------------------------------------------------------
    >
    > 
    File:


    > > > > > Attached File: http://fer3.com/arc/img/119461.f1-img_1189.jpg > > > View and reply to this message: http://fer3.com/arc/m2.aspx?i=119461 > > >

       
    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