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
    Mirages, was: Refraction
    From: Trevor Kenchington
    Date: 2004 Jul 12, 08:44 +0000

    Fred,
    
    An image sunk below the horizon could not be seen and thus could not be
    an image. However, I think what you are getting at is a converse of the
    classic mirage seen in hot, desert areas.
    
    Low-latitude mirages involve light rays bending upwards very near the
    ground, so that we see light from the sky apparently rising from the
    ground. But high-latitude mirages involve the reverse bend, so that
    surface light appears to come from the sky. They are perhaps most common
    in the form of "ice blink", where sunlight reflected off ice beyond the
    horizon is visible as a whiteness in the sky. However, there are reports
    of people seeing, in the sky, inverted images of ships which, in
    reality, are hull-down over the horizon.
    
    I have characterized the two types as "low" and "high" latitude but they
    are, of course, respectively the result of (1) intense solar heating of
    a land surface under cooler air and (2) the presence of warmer air
    overlying a very cold surface.
    
    
    Trevor Kenchington
    
    
    Fred Hebard wrote:
    
    > OK ladies & gentlemen.  We have the case of a mirage, where the image
    > rises above the desert floor.  Are there any counter examples of an
    > image sinking below the horizon?
    
    
    --
    Trevor J. Kenchington PhD                         Gadus{at}iStar.ca
    Gadus Associates,                                 Office(902) 889-9250
    R.R.#1, Musquodoboit Harbour,                     Fax   (902) 889-9251
    Nova Scotia  B0J 2L0, CANADA                      Home  (902) 889-3555
    
                         Science Serving the Fisheries
                          http://home.istar.ca/~gadus
    
    
    

       
    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