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: An exotic lunar distance puzzle
    From: Marcel Tschudin
    Date: 2011 May 5, 20:32 +0300
    Dave,

    Atmospheric refraction exists also above 8 miles. If I remember right, the atmospheric models for calculating refraction generally use a height of about 80km. In your calculation you mixed km and mi. The radius of the earth is about 6400 km (not mi). You are right that the refracted ray has not a constant curvature as shown in the drawing, its bending increases as it passes through air layers closer to the surface.

    Marcel



    On Thu, May 5, 2011 at 7:09 PM, David Fleming <d.l.fleming.1@gmail.com> wrote:

    Marcel your pictures that geometric dip is not the same as a straight line from body to the horizon point. This is correct. Caused by refraction as you showed in curved red line. It is not as shown a smooth arc as I'm guessing you know but experiences the curve only as it enters the atmoshpere which I am not convinced happens a 8 miles height. Could somebody check that?

    cos ( GeoDip) = 1 / ( 1 + (hE/RE)^2)

    take RE = 6378 mi + 8 mi

    he = 211 mi

    GeoDip = 2.68 deg

    Dave Fleming

    ----------------------------------------------------------------
    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