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: USCG Student Example for Low Altitude
    From: Antoine Couëtte
    Date: 2013 Apr 25, 23:26 -0700

    RE : http://fer3.com/arc/m2.aspx/USCG-Student-Example-for-Low-Altitude-Rudzinski-apr-2013-g23682

    Hello Greg,

    Thanks for this example.

    From your chart, I can guess that for your published Azimuth of 077.5° you obtained an intercept (between GPS position itself and LOP) close to 0.8 NM (A).

    I find i = - 1.4' (A) / AZ = 077°7

    Our intercept difference (close to 0.6') comes from a difference in the Value of Refraction (the SUN is at quite a low height). As an example, the refraction differences between US N.A. and French N.A. Tables reach 1 full arc-minute by 0° observed height.

    Best Regards


    AN INTERESTING QUESTION (Any reply anybody ?)

    As the differences between both end results can be appreciable at such low altitudes, should the DIP correction be performed first, and then the Refraction correction, or the other way around ?

    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

    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