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: Swinging the arc: two methods, one preferred
    From: Frank Reed
    Date: 2011 Jan 6, 20:34 -0800

    Hewitt, you wrote:
    "In thinking about this technique further this afternoon, I now visualize it as analogous to inverting the sextant to bring the horizon up to a star. But then, instead of flipping the sextant back to "normal" you hold the scope on the star and rotate the sextant around the axis of the scope. Thus instead of swinging the star (sun, moon, planet) across the horizon, you swing the horizon around the body."

    Yes, that's just right. Now, turn the sextant back right side up and do whatever motion is required to get the same visual effect. You'll find that you're turning from side to side while you're rotating the instrument. As Paul has said, it's hard to describe but easy to do if you follow the simple rule that the Sun or star should remain centered in the field of view. It's not hard to learn at all, and it's not hard to teach if you have the students right there with you. It is, however, hard to explain in words. This whole business would benefit from an animation or a simple video. When you've seen it done, there's nothing to it.

    -FER
    ----------------------------------------------------------------
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com
    ----------------------------------------------------------------

       
    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