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: Extremely poor conditions, details.
    From: Marcel Tschudin
    Date: 2012 Mar 21, 15:57 +0200
    Alexandre E Eremenko, you wrote:
    I repeat: everything looked quite nice. The horizon looked crisp, except
    yes, crisp horizon
    the part under the Sun where there was glare.

    There was only one somewhat strange thing that I noticed.
    There was a very strong glare on the water under the Sun, usual thing.
    So strong that it was uncomfortable to look at it without sunglasses.

    I had no sunglasses, but I tried to look. And what I saw, loked like a "bump"
    on the horizon under Sun. I thought that this must be some optical
    illusion caused by reaction of the eye on the glare ("irradiation" or whatever). Of course, the horizon filter
    filtered the glare, and there was no visible "bump" when looking through the sextant horizon glass with a filter.
    Yes, all this relates to a ducting phenomenon from an inversion which is typical in spring. The setting sun looks then like in the pictures shown here http://mintaka.sdsu.edu/GF/mirages/mirintro.html The "bump" or this line of light (in the last 3 photos) sticks at the horizon. It delays the moment of sunset compred to what one would expect from the sun's movement while its setting, thus indicating that sunlight is ducted. The sun is in such conditions indeed brighter. This is not only an impression. Photos with normal exposures for the setting sun become indeed overexposed.


    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