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: Horizon Shade Polariser
    From: Greg Rudzinski
    Date: 2016 May 6, 13:21 -0700


    As I understand it polarizer pairs block a percentage of light dependant on the relative rotational angle between them from 0° to 90°. Neutral density filters are stacked to block the desired percentage of light. The Sun should appear comfortably dim when using either type of filtering (common sense?). Technical data should be provided with the product used.

    Greg Rudzinski

    From: Francis Upchurch
    Date: 2016 May 6, 18:34 +0100

    May I confirm that polarizing filters offer the same UV light/retina protection as standard filters?



    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Greg Rudzinski
    Sent: 06 May 2016 18:09
    To: francisupchurch---.com
    Subject: [NavList] Re: Horizon Shade Polariser



    If two polarizers are screwed together with one polarizer filter flipped in the frame then you have a variable Sun shade. This is very useful at the index mirror when the sky is overcast, hazy, or partly cloudy. I filter this way when doing DSLR camera CN. I like older Vivitar linear polarizers best for this purpose. C&P uses polarizers stock on their current line of sextants.

    Greg Rudzinski

    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