Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: Sundog
    From: Brad Morris
    Date: 2013 Feb 16, 19:34 -0500



    On Feb 16, 2013 6:45 PM, "Frank Reed" <FrankReed@historicalatlas.com> wrote:

    Bill B, you wrote:
    "Of importance Frank did not specify this is the sundog he saw, but rather the sundog YOU are facing."

    Yes. That was the idea. It was a little puzzle inspired by the photo. This is something that can, in fact, happen. You're out for a walk in the woods near sunset. You see a sundog but can't see the Sun. If you know enough about the Sun's position in the sky, then you can get a pretty decent azimuth, within a degree or so. Another similar case involves determining the Sun's altitude and azimuth when you can see a rainbow, but the Sun itself is not visible for some reason. It's the same idea. A rainbow has a fixed angular relationship with the Sun in the sky. This isn't navigation quality material. It's more about having a quick sense of orientation from some basic knowledge of sky phenomena.

    "To me this means MY sundog could be at any longitude I specify near

    Right. It makes little difference as long as we're talking about observers in the continental US (which I should have specified). The Sun's declination only changes by a few minutes of arc between sunset on the east coast and sunset on the west. Given the single degree precision of the inputs that I specified, and given the rather approximate ability to decide where a sundog begins or ends, that change in declination makes no difference. Even in other longitudes, it would barely matter.

    For Antoine, is there a common name in French for a "sundog"?

    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

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=122390

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    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 Settings

    Posting Code:

    Custom Index

    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