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
    Cross Staff in use, 1574 image
    From: Brad Morris
    Date: 2009 Oct 16, 13:13 -0700

    Attached, please find an image from Cosmographia, Petri Apiani, of the cross staff in use.
    
    This image is consistent with the direction given in Bourne's A Regiment for 
    the Sea, in that the user is directed to align the cross staff to the center 
    of the sun's body.  How in the world was the cross staff operator to know 
    when he was aligned to the center??  
    
    Thus the resultant latitude would always be an estimate, say plus or minus 8 
    arc minutes, based upon the judgement of the operator.  Perhaps in 1574, that 
    was plenty good enough.  
    
    There is plenty of discussion on our list of just what is good enough and how 
    far we should take it.  Clearly, this is not a new topic whatsoever!
    
    Best Regards
    Brad
    
    
    
    
    
    
    File:
    COSMOGRAPHIA-PETRI-APIANI-1574.doc
    --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList+@fer3.com -~----------~----~----~----~------~----~------~--~---

       
    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