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
    Name or NavList Code:
    Email:
       
    Reply
    Re: Moon HP and Earth SD
    From: Lars Bergman
    Date: 2018 May 13, 11:36 -0700

    Frank, you wrote: "Thinking about the view from the Moon would have been considered far too hypothetical and literally outlandish even fifty years ago".

    Wrangel, in 1910 (2nd edition), in "Lärobok i teoretisk och praktisk navigation" wrote "parallax är den vinkel, varunder jordradien synes från en himmelskropp" or, in my translation, "parallax is the angle of the earth's radius as seen from a heavenly body".

    That was written some 110 years ago. Wrangel was the standard work in Sweden during the first quarter or half of the 20th century.

    Lars 

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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