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: SNO-T "night" sight tube?
    From: Alexandre Eremenko
    Date: 2018 Nov 23, 06:47 +0000

    Dear Brad,
    
    You wrote:
    
    > When observing the bright object (sun, moon, planet, star) it should be 
    centered in the optics.  I have scopes which have crosshairs to help insure 
    the object is centered. 
    
    By the way, crosshairs are only possible in Kepler scopes. Not in Galileo scopes.
    
    You also wrote:
    
    > From a brief investigation, I get that AR was commonly available from the 
    1930's or 1940's.  I most certainly could be wrong about that, but it looked 
    like a WW2 enhancement.
    
    I do not remember an exact references, but I read somewhere that it was 
    invented by Germans (Zeiss) shortly before WWII.
    The main producer of Soviet optics after WWII was the company called LOMO 
    (Leningrad optico-mechanical union)
    which used German know-how and equipment. Lens of SNO-T telescopes were apparently made by LOMO.
     
    
    >   What of all the sextants manufactured before AR?  Am I to understand that 
    these devices are incapable of an observation?  Clearly they are not.
    
    Certainly they are not. AR probably gives a slight improvement in twilight 
    observations, better horizon visibility.
    I think that after 1940s or 1950s all binoculars have AR optics.
     
     
    
    Alex.
    

       
    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