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: Star to star angular measurement, beginner
    From: George Huxtable
    Date: 2005 Mar 12, 18:52 +0000

    >On Mar 11, 2005, at 11:16 PM, Frank Reed wrote:
    >>
    >> By the way, parallax, for the Moon, Sun etc. is also an entirely
    >> vertical correction so you can go immediately to the case of lunar
    >> distance calculations from you star-star calculations, if you want.
    >> There's one small issue: the Earth's oblateness yields a slightly
    >> non-vertical component to parallax but that can be dealt with
    >> separately.
    
    And Mark Bernstein asked-
    
    >This brings up the question: why is it called "horizontal parallax"?
    
    =============
    
    And the answer- Because it's the amount of parallax (in a vertical
    direction) that affects an object that's seen horizontally, on the horizon,
    at an altitude of zero degrees. At higher altitudes, the parallax varies as
    cos (alt), becoming zero for an object at the observer's zenith. whan the
    altitude is 90 degrees.
    
    George.
    
    ================================================================
    contact George Huxtable by email at george@huxtable.u-net.com, by phone at
    01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ================================================================
    
    
    

       
    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