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: Refraction:Which formula for Heights below 15°
    From: Paul Hirose
    Date: 2022 May 17, 15:38 -0700

    The Astronomical Almanac has a formula for apparent altitude less than 15°:
    
    R = P [(0.000 02a + 0.0196)a + 0.1594] / [(273 + T)((0.0845a + 0.505)a + 1)]
    
    where R = refraction (degrees), P = pressure (millibars), T =
    temperature (C), a = apparent altitude (deg)
    
    https://archive.org/details/binder1_202003/page/n203/mode/2up?view=theater
    
    --
    Paul Hirose
    sofajpl.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