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: Ebay kollsman periscope sextants
    From: Noell Wilson
    Date: 2018 Jun 8, 09:21 -0700

    Hi Paul,
    I tend to think that mercury would flow without any stiction. It also has very high surface tension so it would tend to stay close to ball form except on the side next to the glass. There wouldn’t be any problem with “bubble” size change.

    Oil - I’m not sure about. I tried baby oil in a bubble. Low surface tension so it leaked and was messy. Water would be better except for freezing and supporting bug growth.

    I may try some mercury in an A-10 bubble with the glasses reversed so the radius is on the bottom. First try might be mercury in air unless someone can think of an ideal high surface tension surrounding fluid. The A-10 uses a reflected bubble image.
    Regards, Noell

    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